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14,900 | Atrial fibrillation: an epidemic in the elderly. | Atrial fibrillation is the most common cardiac arrhythmia that increases in prevalence with age. As the general population grows older, general practitioners will more frequently see this disease in their clinic population. In order to most effectively treat these patients, physicians need to understand key issues, including the use of rhythm control versus ventricular rate control and how to reduce the risk of ischemic stroke. This article will review recent advancements in the understanding of the pathophysiology, management, stroke risk stratification and prevention of thromboembolic complications in atrial fibrillation. |
14,901 | Cardiac responses to the intrapericardial delivery of metoprolol: targeted delivery compared to intravenous administration. | Anti-arrhythmic drugs have narrow therapeutic ranges and typically can engender harmful side effects. The intrapericardial (IP) delivery of anti-arrhythmic agents proposes to achieve higher myocardial levels while minimizing plasma concentrations, thus diminishing systemic side effects. Furthermore, IP delivery enables concentrations at the target site to be more precisely controlled. Our study objective was to compare the relative cardiac effects of intrapericardial administration of metoprolol to standard intravenous (IV) delivery in a swine surgical model. In order to answer the question of how IP metoprolol affects sinus tachycardia, atrial electrophysiology, and pharmacokinetics compared with IV delivery, a medial sternotomy was performed on 21 swine that were divided into three groups: (1) After inducing sinus tachycardia, metoprolol boluses were delivered IP (n = 4) or IV (n = 4); (2) metoprolol was administered either IP (n = 3) or IV (n = 3) with saline controls (n = 3), and electrophysiologic data were collected; (3) metoprolol levels were tracked both in the blood (IV, n = 2) and pericardial (IP, n = 2) fluid. After either IP or IV delivery of metoprolol, heart rates were lowered significantly to 70% and 73% of control rate, respectively. The therapeutic effect of IV-administered metoprolol was considerably reduced after 1 h but was sustained longer in the IP group. Additionally, ventricular contractility and mean arterial pressure parameters were significantly lower in IV-treated animals but were nearly unaffected in IP-treated animals. With IP administration, the elimination half-life of metoprolol in pericardial fluid was 14.4 min with negligible accumulations in the plasma, whereas with IV delivery, the elimination half-life in plasma was 11.1 min with negligible amounts found in the pericardial fluid. The targeted intrapericardial delivery of metoprolol effectively lowers heart rates for sustained periods of time, with minimal effect on either ventricular contractility or mean arterial pressure. We did not observe dramatic changes in induced atrial fibrillation times or refractory periods using this model. |
14,902 | KCNJ2 variant of unknown significance reclassified as long QT syndrome causing ventricular fibrillation. | KCNJ2 is the only gene implicated in Andersen-Tawil syndrome. Sudden cardiac arrest is rare in Andersen-Tawil syndrome. However, sudden cardiac arrest is often the index presentation in other forms of long QT syndrome. We present an unreported variant in the KCNJ2 gene, associated with long QT syndrome, that presented with ventricular fibrillation. Exercise testing and adrenaline infusion were useful in assigning pathogenicity to this variant of unknown significance. |
14,903 | [The contractile function and electrical stability of the heart in different regimens of physical exercise]. | Adaptation to moderate duration of physical loading causes identical levels of increase in threshold fibrillation of ventricles in wide range of their intensity. Rise of contractile heart function increases with prolonged adaptation regimen of heavy loading exercise. With hypokinesia and excessive physical load the sinking of threshold of fibrillation of ventricles occurs in lacking of alterations and with high contractile function of the heart respectively. |
14,904 | A modified subcutaneous implantable cardioverter-defibrillator implant in a patient with a previous left ventricular epicardial defibrillation patch. | We describe a case of subcutaneous implantable cardioverter-defibrillator (ICD) implant in a patient with an existing epicardial defibrillation patch. Potential issues with shock vector shielding were overcome by a modification of the generator implant site and poor sensing were successfully managed by programming a sensing vector which excluded the generator. |
14,905 | A detailed guide for quantification of myocardial scar with the Selvester QRS score in the presence of electrocardiogram confounders. | The Selvester QRS score translates subtle changes in ventricular depolarization measured by the electrocardiogram into information about myocardial scar location and size. This estimated scar has been shown to have a high degree of correlation with autopsy-measured myocardial infarct size. In addition, multiple studies have demonstrated the value of the QRS score in post-myocardial infarct patients to provide prognostic information. Recent studies have demonstrated that increasing QRS score is predictive of increased implantable defibrillator shocks for ventricular tachycardia and fibrillation as well as decreased response to cardiac resynchronization therapy. Although QRS scoring has never achieved widespread clinical use, increased interest in patient selection and risk-stratification techniques for implantable defibrillators and cardiac resynchronization therapy has led to renewed interest in QRS scoring and its potential to identify which patients will benefit from device therapy. The QRS score criteria were updated in 2009 to expand their use to a broader population by accounting for the different ventricular depolarization sequences in patients with bundle-branch/fascicular blocks or ventricular hypertrophy. However, these changes also introduced additional complexity and nuance to the scoring procedure. This article provides detailed instructions and examples on how to apply the QRS score criteria in the presence of confounding conduction types to facilitate understanding and enable development and application of automated QRS scoring. |
14,906 | Ultrastructural evidence of mitochondrial abnormalities in postresuscitation myocardial dysfunction. | Though there is evidence to implicate that the mitochondrion may play an important role in the development of postresuscitation myocardial dysfunction, limited data are available regarding the ultrastructural alterations of the mitochondria, mitochondrial energy-producing ability, and their relationship to postresuscitation myocardial dysfunction. This study was designed to determine whether mitochondrial abnormalities contribute to the development of postresuscitation myocardial dysfunction.</AbstractText>Fifteen anesthetized male Sprague-Dawley rats were randomized to: (1) global myocardial ischemia/reperfusion, in which 8 min of ventricular fibrillation was induced and successful defibrillation was achieved after 6 min of cardiopulmonary resuscitation (CPR); (2) global myocardial ischemia, in which ventricular fibrillation and CPR were performed without defibrillation attempt; and (3) sham control.</AbstractText>Myocardial function was significantly impaired after resuscitation. Mitochondria were massively swollen in global ischemic hearts and mildly swollen in the resuscitated hearts. Concomitantly, ATP levels abruptly declined during global ischemia and partially recovered after resuscitation. Furthermore, mitochondrial abnormalities were supported by the incapability of utilizing energy substrates manifested by the accumulations of intramyocellular lipid droplets and glycogen deposits.</AbstractText>In this model of cardiac arrest and CPR, the presence of ultrastructural mitochondrial abnormalities, further evidenced by the incapability of utilizing energy substrates and impairment of energy-production, might, in part, contribute to the development of postresuscitation myocardial dysfunction.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,907 | [Myocardial infarction in a 16-year old following inhalation of butane gas]. | Butane gas is inhaled by young people with the aim of getting 'high'. This can cause coronary spasm with myocardial infarction and ventricular fibrillation as a result.</AbstractText>We report on a 16-year-old male who collapsed at home after sniffing butane. His father, together with a paramedical emergency team that had found ventricular fibrillation, started basic and advanced life support. ECG showed exaggerated ST-elevations and an echocardiography showed a hypokinetic anterior ventricular wall and ventricular septum. After treatment with dobutamine, nitroglycerine, acetylsalicylic acid and dalteparine, the ECG and left ventricular function improved. He was admitted to a pediatric intensive care unit where he was artificially ventilated for 4 days and treated for cardiogenic shock. In the following days his cardiovascular condition improved. Magnetic resonance imaging showed no ischaemic damage of the brain. At 6 weeks his general condition was not as before, but ECG and cardiac function had almost recovered.</AbstractText>Young people who experiment with inhalation of volatile substances generally do not know how dangerous this is. Provision of information about the possible consequences will have a preventive effect.</AbstractText> |
14,908 | Long-term clinical impact of functional mitral regurgitation after aortic valve replacement. | We evaluated the impact of functional mitral regurgitation (MR) on clinical outcomes and to identify predictors of residual MR after aortic valve replacement in aortic stenosis.</AbstractText>Three hundred and eighty-four patients who underwent primary aortic valve replacement for aortic stenosis were enrolled. Patients were divided into the no-MR group (no or trivial MR; n = 270) and the MR group (mild to moderate MR; n = 114). In the MR group, 19 patients underwent concomitant mitral valve repairs. Mean follow-up duration was 4.5 ± 3.7 years (range, 1 to 15 years). Clinical and echocardiographic data were analyzed.</AbstractText>There was no operative mortality, but there were 9 late cardiac deaths (2.3%). Freedom from cardiac death at 14 years was lower in the MR group than in the no-MR group (77.8% ± 12.6% versus 97.7% ± 1.4%, respectively; p = 0.045), and freedom from heart failure events at 10 years was also lower in the MR group (60.8% ± 13.4% versus 92.6% ± 2.2%, p = 0.043). On multivariate analysis, preoperative atrial fibrillation and left ventricular ejection fraction greater than 40% were predictors for residual MR at late follow-up in the untreated MR group. Cox regression analysis demonstrated that postoperative moderate MR predicted late cardiac death (p = 0.016, hazard ratio 5.2). In the MR group, the incidence of residual MR in patients who underwent mitral valve repair was 5.6% (versus 30.7% in patients without mitral valve repair, p = 0.001).</AbstractText>Functional MR in aortic stenosis was related to poor clinical outcomes. The results of this study suggest that concomitant mitral valve procedures could be considered in selected patients with aortic stenosis and functional MR.</AbstractText>Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,909 | Gender differences of atrial and ventricular remodeling and autonomic tone in nonelite athletes. | Veteran endurance athletes have an increased risk of developing atrial fibrillation (AF), with a striking male predominance. We hypothesized that male athletes were more prone to atrial and ventricular remodeling and investigated the signal-averaged P wave and factors that promote the occurrence of AF. Nonelite athletes scheduled to participate in the 2010 Grand Prix of Bern, a 10-mile race, were invited. Of the 873 marathon and nonmarathon runners who were willing to participate, 68 female and 70 male athletes were randomly selected. The runners with cardiovascular disease or elevated blood pressure (>140/90 mm Hg) were excluded. Thus, 121 athletes were entered into the final analysis. Their mean age was 42 ± 7 years. No gender differences were found for age, lifetime training hours, or race time. The male athletes had a significantly longer signal-averaged P-wave duration (136 ± 12 vs 122 ± 10 ms; p <0.001). The left atrial volume was larger in the male athletes (56 ± 13 vs 49 ± 10 ml; p = 0.001), while left atrial volume index showed no differences (29 ± 7 vs 30 ± 6 ml/m²; p = 0.332). In male athletes, the left ventricular mass index (107 ± 17 vs 86 ± 16 g/m²; p <0.001) and relative wall thickness (0.44 ± 0.06 vs 0.41 ± 0.07; p = 0.004) were greater. No differences were found in the left ventricular ejection fraction (63 ± 4% vs 66 ± 6%; p = 0.112) and mitral annular tissue Doppler e' velocity (10.9 ± 1.5 vs 10.6 ± 1.5 cm/s; p = 0.187). However, the tissue Doppler a' velocity was higher (8.7 ± 1.2 vs 7.6 ± 1.3 cm/s; p < 0.001) in the male athletes. Male athletes had a higher systolic blood pressure at rest (123 ± 9 vs 110 ± 11 mm Hg; p < 0.001) and at peak exercise (180 ± 15 vs 169 ± 19 mm Hg; p = 0.001). In the frequency domain analysis of heart rate variability, the sympatho-vagal balance, represented by the low/high-frequency power ratio, was significantly greater in male athletes (5.8 ± 2.8 vs 3.9 ± 1.9; p < 0.001). Four athletes (3.3%) had at least one documented episode of paroxysmal AF, all were men (p = 0.042). In conclusion, for a comparable amount of training and performance, male athletes showed a more pronounced atrial remodeling, a concentric type of ventricular remodeling, and an altered diastolic function. A higher blood pressure at rest and during exercise and a higher sympathetic tone might be causal. The altered left atrial substrate might facilitate the occurrence of AF. |
14,910 | Sodium nitroprusside enhanced cardiopulmonary resuscitation (SNPeCPR) improves vital organ perfusion pressures and carotid blood flow in a porcine model of cardiac arrest. | To describe a new method of CPR that optimizes vital organ perfusion pressures and carotid blood flow. We tested the hypothesis that a combination of high dose sodium nitroprusside (SNP) as well as non-invasive devices and techniques known independently to enhance circulation would significantly improve carotid blood flow (CBF) and return of spontaneous circulation (ROSC) rates in a porcine model of cardiac arrest.</AbstractText>15 isofluorane anesthetized pigs (30±1 kg), after 6 min of untreated ventricular fibrillation, were subsequently randomized to receive either 15 min of standard CPR (S-CPR) (8 animals) or 5 min epochs of S-CPR followed by active compression-decompression (ACD)+inspiratory impedance threshold device (ITD) CPR followed by ACD+ITD+abdominal binding (AB) with 1mg of SNP administered at minutes 2, 7, 12 of CPR (7 animals). Primary endpoints were CBF and ROSC rates. ANOVA and Fisher's exact test were used for comparisons.</AbstractText><AbstractText Label="RESULTS/CONCLUSION" NlmCategory="CONCLUSIONS">There was significant improvement in the hemodynamic parameters in the SNP animals. ROSC was achieved in 7/7 animals that received SNP and in 2/8 in the S-CPR (p=0.007). CBF and end tidal CO(2) (ETCO(2)) were significantly higher in the ACD+ITD+AB+SNP (SNPeCPR) animals during CPR. Bolus doses of SNP, when used in conjunction with ACD+ITD+AB CPR, significantly improve CBF and ROSC rates compared to S-CPR.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,911 | Therapeutic hypothermia is associated with improved neurologic outcome and survival in cardiac arrest survivors of non-shockable rhythms. | Therapeutic hypothermia improves neurologic outcomes in patients resuscitated from cardiac arrest due to ventricular fibrillation. However, its role in patients with cardiac arrest due to non-shockable rhythms (pulseless electrical activity (PEA) and asystole) is unclear. We hypothesized that therapeutic hypothermia favorably impacts neurologic outcome and survival in patients resuscitated from cardiac arrest due to non-shockable rhythms.</AbstractText>Retrospectively collected data on consecutive adult patients admitted to Hartford Hospital from 1/1/2004 to 11/1/2010 who survived a cardiac arrest due to PEA or asystole were analyzed. Patients who underwent therapeutic hypothermia (1/1/2007-11/1/2010) formed the hypothermia group while patients admitted prior to the institution of therapeutic hypothermia (1/1/2004-1/1/2007) at Hartford Hospital formed the control group. The primary end-point was measured using the Pittsburgh cerebral performance category (CPC) scale and patients were assessed for a good (CPC 1 and 2) or poor (CPC 3-5) neurological outcome prior to discharge from hospital. A secondary end-point was measured as survival at discharge from hospital.</AbstractText>Of 100 post-cardiac arrest patients included in the study, 15/52 (29%) patients in the hypothermia group had a good neurologic outcome as compared to 5/43 (10%) patients in the control group (P=0.021). On multivariate analysis, the odds ratio for good neurologic outcome and survival at discharge from the hospital with therapeutic hypothermia as compared to control were 4.35 (95% CI 1.10-17.24, P=0.04) and 5.65 (CI 1.66-19.23, P=0.006) respectively.</AbstractText>Therapeutic hypothermia is associated with favorable neurologic outcome and survival in patients resuscitated after cardiac arrest due to non-shockable rhythms.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,912 | Atrial remodeling and the substrate for atrial fibrillation in rat hearts with elevated afterload. | Although arterial hypertension and left ventricular hypertrophy are considered good epidemiological indicators of the risk of atrial fibrillation (AF) in patients, the link between elevated afterload and AF remains unclear. We investigated atrial remodeling and the substrate for arrhythmia in a surgical model of elevated afterload in rats.</AbstractText>Male Wistar rats (aged 3-4 weeks) were anesthetized and subjected to either partial stenosis of the ascending aorta (AoB) or sham operation (Sham). Experiments were performed on excised hearts 8, 14, and 20 weeks after surgery. Unipolar electrograms were recorded from the left atrial epicardial surface of perfused hearts using a 5×5 electrode array. Cryosections of left atrial tissue were retained for histological and immunocytochemical analyses. Compared to Sham, AoB hearts showed marked left atrial hypertrophy and fibrosis at 14 and 20 weeks postsurgery. The incidence and duration of pacing-induced AF was increased in hearts from AoB rats at 20 weeks postsurgery. The substrate for arrhythmia was associated with reduced vectorial conduction velocity and greater inhomogeneity in conduction but without changes in effective refractory period. Left atrial expression of the gap junction protein, connexin43, was markedly reduced in AoB compared with Sham hearts.</AbstractText>Using a small-animal model, we demonstrate that elevated afterload in the absence of systemic hypertension results in increased inducibility of AF and left atrial remodeling involving fibrosis, altered atrial connexin43 expression, and marked conduction abnormalities.</AbstractText> |
14,913 | Quality of care and outcomes in women hospitalized for heart failure. | Although women account for a significant proportion of heart failure (HF) hospitalizations, data on the quality of care and in-hospital outcomes in women are limited.</AbstractText>We examined The Joint Commission performance measures, other quality metrics, length of stay, and in-hospital mortality in women using 99 841 HF admissions (January 2005 to June 2009) at 248 hospitals participating in the American Heart Association Get With The Guidelines-Heart Failure registry. Women accounted for 50% of the HF admissions and were older (mean age, 74±14 versus 69±14 years), more likely to have hypertension (77% versus 72%), and less likely to have coronary disease (44% versus 53%) or renal insufficiency (18% versus 23%) than men (all P<0.001). The presenting symptoms were similar to men, but women had higher admission systolic blood pressure (mean, 144±31 versus 137±30 mm Hg; P<0.001) and ejection fraction (mean, 0.44±0.17% versus 0.34±0.16%; P<0.001). After adjustment for baseline differences, eligible women were less likely than men to have measurement of left ventricular function (adjusted odds ratio [OR], 0.81; 95% CI, 0.76 to 0.86) and to receive anticoagulation for atrial fibrillation (adjusted OR, 0.91; 95% CI, 0.86 to 0.96) or implantable cardioverter-defibrillators (adjusted OR, 0.70; 95% CI, 0.65 to 0.75) but were as likely to receive discharge instructions, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and smoking cessation counseling at discharge. Although the median length of stay was 4 days, women were more likely than men to be hospitalized >4 days (adjusted OR, 1.13; 95% CI, 1.10 to 1.16) and >7 days (adjusted OR, 1.07; 95% CI, 1.04 to 1.11). Women had comparable in-hospital mortality to men (adjusted OR, 1.05; 95% CI, 0.96 to 1.14).</AbstractText>Compared to men, women hospitalized for HF differ in many clinical characteristics and length of stay but have similar clinical presentations, receive similar quality of care for most but not all measures, and experience similar in-hospital mortality.</AbstractText> |
14,914 | Management of patients with atrial fibrillation: specific considerations for the old age. | Atrial fibrillation (AF) is the commonest of all sustained arrhythmias, and most of the patients seeking medical therapy are in the elderly age group. The management of these patients is particularly difficult due to associated comorbidities. Hypertension, congestive heart failure, left ventricular hypertrophy, and coronary artery disease are often present in the elderly patient population, and therefore, antiarrhythmic drugs often fail due to side effects, proarrhythmia, or poor rhythm control. Recently, radiofrequency catheter ablation has been widely performed as an efficient therapy for recurrent, drug-refractory AF. Nevertheless, patients at old age were underrepresented in prior AF ablation trials, and the current guidelines for catheter ablation of AF recommend a noninvasive approach in the elderly patient group due to the lack of clinical data supporting ablation therapy. However, study results of our group and others are suggesting that catheter ablation is a safe and effective treatment for patients over the age of 65 years with symptomatic, drug-refractory AF, and therefore, patients should not be precluded from catheter ablation only on the basis of age. This paper discusses the pharmacological (rhythm control, rate control, and anticoagulation) and catheter management of AF in the elderly population. |
14,915 | Relationship between N-terminal pro-B-type natriuretic peptide and renal function: the effects on predicting early outcome after off-pump coronary artery bypass surgery. | Plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) provide useful prognostic predictors in patients after cardiac surgery. However, predictive accuracy of NT-proBNP levels has varied significantly according to renal dysfunction. The purpose of this study was to assess whether preoperative NT-proBNP levels could be used as predictors of early postoperative outcomes on the basis of renal function in patients undergoing off-pump coronary artery bypass surgery (OPCAB).</AbstractText>In 219 patients undergoing elective OPCAB, NT-proBNP and an estimated glomerular filtration rate (eGFR) were assessed preoperatively. All patients were divided into 3 groups according to tertiles of eGFR: the first (eGFR ≥ 90 ml/min/1.73 m(2)), the second (90 ml/min/1.73 m(2) > eGFR ≥ 72 ml/min/1.73 m(2)) and the third tertile group (eGFR < 72 ml/min/1.73 m(2)). End point was the composite of early postoperative complications defined as myocardial infarction, new onset atrial fibrillation, ventricular dysfunction, prolonged mechanical ventilator care (> 48 hr), prolonged ICU stay (≥ 3 days), and in hospital mortality.</AbstractText>There was no difference in early postoperative complications among groups. A preoperative NT-proBNP level of 228 pg/ml and 302 pg/ml (sensitivity 70%, specificity 67%, P < 0.001 and sensitivity 73%, specificity 63%, P = 0.001, respectively) were optimal cut-off values predicting complicated early postoperative course in second and third tertile group, respectively.</AbstractText>Preoperative NT-proBNP levels seem to be predictive of early postoperative complications in patients with eGFR < 90 ml/min/1.73 m(2) undergoing OPCAB.</AbstractText> |
14,916 | Apical hypertrophic cardiomyopathy. | We describe a patient with asymptomatic apical hypertrophic cardiomyopathy (AHCM) who later developed cardiac arrhythmias, and briefly discuss the diagnostic modalities, differential diagnosis and treatment option for this condition. AHCM is a rare form of hypertrophic cardiomyopathy which classically involves the apex of the left ventricle. AHCM can be an incidental finding, or patients may present with chest pain, palpitations, dyspnea, syncope, atrial fibrillation, myocardial infarction, embolic events, ventricular fibrillation and congestive heart failure. AHCM is frequently sporadic, but autosomal dominant inheritance has been reported in few families. The most frequent and classic electrocardiogram findings are giant negative T-waves in the precordial leads which are found in the majority of the patients followed by left ventricular (LV) hypertrophy. A transthoracic echocardiogram is the initial diagnostic tool in the evaluation of AHCM and shows hypertrophy of the LV apex. AHCM may mimic other conditions such as LV apical cardiac tumors, LV apical thrombus, isolated ventricular non-compaction, endomyocardial fibrosis and coronary artery disease. Other modalities, including left ventriculography, multislice spiral computed tomography, and cardiac magnetic resonance imagings are also valuable tools and are frequently used to differentiate AHCH from other conditions. Medications used to treat symptomatic patients with AHCM include verapamil, beta-blockers and antiarrhythmic agents such as amiodarone and procainamide. An implantable cardioverter defibrillator is recommended for high risk patients. |
14,917 | Effect of prophylactic amiodarone in patients with rheumatic valve disease undergoing valve replacement surgery. | The study was carried out to evaluate the effect of prophylactic single-dose intravenous amiodarone in patients undergoing valve replacement surgery. Maintenance of sinus rhythm is better than maintenance of fixed ventricular rate in atrial fibrillation (AF) especially in the presence of irritable left or right atrium because of enlargement. Fifty-six patients with valvular heart disease with or without AF were randomly divided into two groups. Group I or the amiodarone group (n=28) received amiodarone (3 mg/kg in 100 ml normal saline) and group II or the control group received same volume of normal saline. The standardized protocol for cardiopulmonary bypass was maintained for all the patients. AF occurred in 7.14% patients in group I, and in group II, 28.57% (P=0.035); ventricular tachycardia/fibrillation was observed in 21.43% patients in group I and 46.43% patients in group II (P=0.089) after release of aortic clamp. Most of the patients in group I (92.86%) maintained sinus rhythm without cardioversion or defibrillation after release of aortic cross clamp (P=0.002). Defibrillation or cardio version was needed in 7.14% patients in group I and 28.57% patients in group II (P=0.078). A single prophylactic intraoperative dose of intravenous amiodarone decreased post bypass arrhythmia in this study in comparison to the control group. Single dose of intraoperative amiodarone may be used to decrease postoperative arrhythmia in open heart surgery. |
14,918 | Evaluation of arrhythmia scoring systems and exercise-induced cardioprotection. | Exercise is protective against ventricular arrhythmias induced by ischemia (I), the condition of inadequate blood flow, and reperfusion (R), the reestablishment of blood flow. This protection is observed clinically and scientifically by decreased incidence in ECG abnormalities. Numerous scoring systems exist for the quantification of ventricular arrhythmia severity. On the basis of preventricular contractions, ventricular tachycardia, and ventricular fibrillation frequency, these scoring systems are intended to provide more robust ECG outcome indicators than individual arrhythmia variables. Scoring systems vary primarily on continuous versus discontinuous treatment of the data, which should be considered when matching these arrhythmia metrics to scientific applications.</AbstractText>The aim of this investigation was to evaluate seven ECG scoring systems in the assessment of ventricular arrhythmia severity after IR in male Sprague-Dawley rats.</AbstractText>Animals remained sedentary or exercised (3 d of treadmill exercise for 60 min) before surgically induced IR. A subset of sedentary animals served as sham, undergoing surgical procedure without IR. ECGs were evaluated under blinded conditions by three trained individuals. Single arrhythmia data and the parametric score were analyzed by one-way ANOVA, whereas the Kruskal-Wallis was used to compare group means for all nonparametric scoring systems between groups.</AbstractText>IR produced a significant arrhythmic response in exercised and sedentary rats as determined by all arrhythmia scoring systems. Four arrhythmia metrics resulted in significant differences between exercised and sedentary treatments (P < 0.001), whereas three metrics did not.</AbstractText>Continuous versus discontinuous treatment of the data may account for variation in scoring system outcomes. These data confirm that exercise protects against IR-induced arrhythmias, and care must be taken when selecting an arrhythmia scoring system for ECG evaluation.</AbstractText> |
14,919 | Comparison of mortality and morbidity in patients with atrial fibrillation and heart failure with preserved versus decreased left ventricular ejection fraction. | Almost 50% of patients with congestive heart failure (HF) have preserved ejection fraction (PEF). Data on the effect of HF-PEF on atrial fibrillation outcomes are lacking. We assessed the prognostic significance of HF-PEF in an atrial fibrillation population compared to a systolic heart failure (SHF) population. A post hoc analysis of the National Heart, Lung, and Blood Institute-limited access data set of the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial was carried out. The patients with a history of congestive HF and a preserved ejection fraction (EF >50%) were classified as having HF-PEF (n = 320). The patients with congestive HF and a qualitatively depressed EF (EF <50%) were classified as having SHF (n = 402). Cox proportional hazards analysis was performed. The mean follow-up duration was 1,181 ± 534 days/patient. The patients with HF-PEF had lower all-cause mortality (hazard ratio [HR] 0.62, 95% confidence interval [CI] 0.46 to 0.85, p = 0.003) and cardiovascular mortality (HR 0.56, 95% CI 0.38 to 0.84, p = 0.006), with a possible decreased arrhythmic end point (HR 0.39, 95% CI 0.16 to 1.006, p = 0.052) than did the patients with SHF. No differences were observed for ischemic stroke (HR 1.08, 95% CI 0.48 to 2.39, p = 0.86), rehospitalization (HR 0.89, 95% CI 0.75 to 1.07, p = 0.24), or progression to New York Heart Association class III-IV (odds ratio 0.80, 95% CI 0.42 to 1.54, p = 0.522). In conclusion, although patients with HF-PEF have better mortality outcomes than those with SHF, the morbidity appears to be similar. |
14,920 | Effect of sodium-channel blockade on early repolarization in inferior/lateral leads in patients with idiopathic ventricular fibrillation and Brugada syndrome. | A high incidence of early repolarization (ER) pattern in the inferolateral leads has been reported in patients with idiopathic ventricular fibrillation (IVF). Brugada syndrome (BS) is characterized by J-point or ST-segment elevation in the right precordial leads and ventricular fibrillation, and some patients with BS also have ER in the inferolateral leads.</AbstractText>To compare the clinical characteristics and effects of sodium-channel blockade on ER between IVF patients with ER (early repolarization syndrome [ERS]) and BS patients with or without ER.</AbstractText>Fourteen patients with ERS and 21 patients with BS were included in this study. ER was defined as an elevation of at least 0.1 mV from baseline in the QRS-T junction in the inferorolateral leads. Provocative tests with sodium-channel blockers were conducted in all patients with ERS to distinguish ERS from BS.</AbstractText>In the ERS group, all patients were male and most patients experienced ventricular fibrillation during sleep or low activity (79%). ER was attenuated by sodium-channel blockers in most patients with ERS (13/14, 93%) and BS (5/5, 100%), whereas ST-segment elevation was augmented in the right precordial leads in the BS group. The rates of positive late potentials were significantly higher in the BS group (60%) than in the ERS group (7%) (P <.01).</AbstractText>Some similarities were observed between ERS and BS, including gender, arrhythmia triggers, and response of ER to sodium-channel blockers. Unlike the ST segment in the right precordial leads in BS, ER was attenuated in patients with both ERS and BS, suggesting a differential mechanism between ER in the inferolateral leads and ST elevation in the right precordial leads.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,921 | Bi-stable wave propagation and early afterdepolarization-mediated cardiac arrhythmias. | In normal atrial and ventricular tissue, the electrical wavefronts are mediated by the fast sodium current (I(Na)), whereas in sinoatrial and atrioventricular nodal tissue, conduction is mediated by the slow L-type calcium current (I(Ca,L)). However, it has not been shown whether the same tissue can exhibit both the I(Na)-mediated and the I(Ca,L)-mediated conduction.</AbstractText>This study sought to test the hypothesis that bi-stable cardiac wave conduction, mediated by I(Na) and I(Ca,L), respectively, can occur in the same tissue under conditions promoting early afterdepolarizations (EADs), and to study how this novel wave dynamics is related to the mechanisms of EAD-mediated arrhythmias.</AbstractText>Computer models of two-dimensional (2D) tissue with a physiologically detailed action potential model were used to study the bi-stable wave dynamics. Theoretical predictions were tested experimentally by optical mapping in neonatal rat ventricular myocyte monolayers.</AbstractText>In the same 2D homogeneous tissue, we could induce spiral waves that are mediated by either I(Na) or I(Ca,L) under conditions in which the action potential model exhibited EADs. This bi-stable wave propagation behavior was similar to bi-stability shown in many other nonlinear systems. Because the bi-stable states are also excitable, we call this novel behavior bi-excitability. In a 2D heterogeneous tissue, the I(Ca,L)-mediated spiral wave meanders, giving rise to a twisting electrocardiographic QRS axis, resembling torsades de pointes, whereas the coexistence and interplay between the I(Na)-mediated wavefronts and I(Ca,L)-mediated wavefronts give rise to polymorphic ventricular tachycardia. We also present experimental evidence for bi-excitability under EAD-promoting conditions in neonatal rat ventricular myocyte monolayers exposed to BayK8644 and isoproterenol.</AbstractText>Under EAD-prone conditions, both I(Na)-mediated conduction and I(Ca,L)-mediated conduction can occur in the same tissue. These novel wave dynamics may be responsible for certain EAD-mediated arrhythmias, such as torsades de pointes and polymorphic ventricular tachycardia.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,922 | Clinical and electrocardiographic characteristics of patients with short QT interval in a large hospital-based population. | Short QT syndrome is one of the underlying disorders associated with ventricular fibrillation. However, the precise prognostic implication of a short QT interval remains unclear.</AbstractText>The purpose of this study was to investigate the prevalence and long-term prognosis in patients with a shorter-than-normal QT interval in a large hospital-based population.</AbstractText>We chose patients with a short Bazett QTc interval from a database consisting of 114,334 patients to determine the clinical characteristics and prognostic value of a short QT interval.</AbstractText>A total of 427 patients (mean age 43.4 ± 22.4 years) had a short QT interval with about a 1.2 times higher male predominance (234 men). The QTc interval was significantly longer in female than in male patients (363.8 ± 6.1 ms vs 357.1 ± 5.8 ms, P <.0001). The age-specific prevalence of patients with short QT interval was biphasic, peaking at young and old age. Atrial fibrillation and early repolarization were complicated with short QT interval in 39 (9.1%) and 26 (6.1%) patients, respectively. The prognosis of 327 patients (182 men; mean age, 46.4 ± 27.3 years) with a short QT interval could be assessed (mean follow-up period, 54.0 ± 62.0 months). During the follow-up, 2 patients, 1 of whom had early repolarization, developed life-threatening events, in contrast to 6 patients who died of noncardiac causes and did not have early repolarization.</AbstractText>The prevalence of a short QT interval showed a slight male preponderance and biphasic age-dependent distribution in both genders. The complication rate of atrial fibrillation was higher in those with a short QT interval than in general populations. The long-term outcome suggested that early repolarization in a short QT interval might be associated with potential risk of lethal arrhythmia.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,923 | Risk factors and consequences of atrial fibrillation with rapid ventricular response in patients with ischemic stroke treated with intravenous thrombolysis. | Atrial fibrillation (AF) is associated with rapid ventricular response (RVR) that increases myocardial demand and blood pressure instability. We investigated the incidence, risk factors, and outcomes of RVR among patients with ischemic stroke receiving treatment with intravenous (IV) recombinant tissue plasminogen activator (rtPA). Consecutive patients with AF who received IV rtPA within 3 hours of symptom onset were included. Vascular risk factors, stroke characteristics, and outcome measures were compared between patients who developed RVR and those who did not. Eighty patients with AF (mean age, 79 years; 46% men) who underwent rtPA treatment were studied. Nineteen (24%) of these patients developed RVR and were treated with IV rate-controlling medications. A bimodal pattern of distribution was observed in the occurrence of RVR, with the first peak occurring within 12 hours of stroke onset and the second peak occurring 24-48 hours after onset. Compared with the patients without RVR, those with RVR stayed a median duration of 1.2 days longer in the intensive care unit (P = .048). There were no differences in functional recovery and hemorrhagic outcomes between the patients with RVR and those without RVR. We observed a 16-hour delay in the resumption of antiarrhythmic medications (either at previous or reduced dosage) in the patients who subsequently developed RVR (median time from stroke onset, 29 hours vs 13 hours; P = .040). Our findings suggest that a delay in the resumption of rate-control medications in patients with AF may result in RVR and prolong the use of intensive care resources. |
14,924 | The fifth chamber of the heart: huge left atrial aneurysm. | Cardiomegaly is a common but nonspecific finding in the emergency department. The etiology may be explained by left ventricular dilation, biventricular dilation, right ventricular dilation, or pericardial abnormalities, or it may be found to be spurious on the echocardiogram. Rarely, isolated abnormalities of the atrium, particularly the left atrium, may cause abnormalities on the chest radiograph but will not cause true cardiomegaly. We reported a 37-year-old woman who presented with persistent palpitation of a 6-hour duration. An electrocardiogram revealed atrial fibrillation with rapid ventricular response. A chest radiograph showed cardiomegaly with unusual prominence of the left heart border. A subsequent transthoracic echocardiography demonstrated an echo-free chamber adjacent to the left lateral wall of the left ventricle. The diagnosis of a rare huge left atrial aneurysm was finally established by multidetector-row computed tomography, which had been seldom used as a diagnostic tool in the past. Patients with this cardiac anomaly usually are asymptomatic until the second or third decade of life, when the aneurysms can reach remarkable sizes and are often complicated with atrial tachyarrhythmia or thromboembolic events. Early surgical intervention is advised even in asymptomatic patients to prevent the occurrence of myocardial dysfunction, atrial fibrillation, and systemic embolism. |
14,925 | Effect of short-acting beta blocker on the cardiac recovery after cardiopulmonary bypass. | The objective of this study was to investigate the effect of beta blocker on cardiac recovery and rhythm during cardiac surgeries. Sixty surgical rheumatic heart disease patients were received esmolol 1 mg/kg or the same volume of saline prior to removal of the aortic clamp. The incidence of cardiac automatic re-beat, ventricular fibrillation after reperfusion, the heart rate after steady re-beat, vasoactive drug use during weaning from bypass, the posterior parallel time and total bypass time were decreased by esmolol treatment.</AbstractText>Esmolol has a positive effect on the cardiac recovery in cardiopulmonary bypass surgeries.</AbstractText> |
14,926 | Assessing global and regional left ventricular myocardial function in elderly patients using the bidimensional strain method. | Biological and anatomical alterations in the elderly result in modifications of the myocardial deformation detected previously by magnetic resonance imaging (MRI) technology and could have consequences on speckle tracking's parameters in this patient population.</AbstractText>To compare left ventricular (LV) 2D strain between elderly patients and young individuals without heart disease.</AbstractText>Patients without history of cardiac disease were enrolled from the geriatric department. After echocardiographic examination, exclusion criteria were LV myocardial abnormality, valve disease, and atrial fibrillation. The control group consisted of healthy subjects from the medical staff. 2D strain values were obtained from 16 segments in four-, three-, and two-chamber apical views for longitudinal and transversal strains, and from six basal segments in short-axis view for circumferential strain.</AbstractText>Forty-five elderly patients (35 females) with mean age of 83.4±5.0 years (75-95 years) and 45 young subjects (28 females) with mean age of 33.6±7.5 years (17-45 years) were assessed. There was no difference between the two groups considering LV ejection fraction (66±6% vs. 65±4%, P=ns). Feasibility of segmental 2D strain was 55.6% for circumferential strain, 63% for transversal strain, and 82% for longitudinal strain. Global longitudinal strain was significantly lower in elderly patients (-20.9±1.9% vs. -22.2±2.2%, P<0.01). There was no significant difference in global transversal and circumferential strain.</AbstractText>Aging results in a decrease in global longitudinal strain. This should be taken into account in the assessment of pathological myocardial dysfunction.</AbstractText>© 2011, Wiley Periodicals, Inc.</CopyrightInformation> |
14,927 | Diastolic dysfunction in patients undergoing cardiac surgery: a pathophysiological mechanism underlying the initiation of new-onset post-operative atrial fibrillation. | Our goal was to investigate whether left ventricular (LV) diastolic dysfunction was an important pathophysiological mechanism underlying the initiation of new-onset post-operative atrial fibrillation (POAF).</AbstractText>Atrial fibrillation is a common complication after cardiac surgery. However, the precise mechanism underlying its development remains poorly understood. Pre-existing alterations of myocardial diastolic function may predispose patients to the development of POAF.</AbstractText>Patients were residents of Olmsted County, Minnesota, who underwent complete LV diastolic function assessment before coronary artery bypass grafting and/or valve surgery between January 1, 2000, and December 31, 2005. All were in sinus rhythm and had no history of atrial fibrillation, a pacemaker, mitral stenosis, or congenital heart disease. POAF was defined as any episode of atrial fibrillation within 30 days after surgery.</AbstractText>POAF occurred in 135 of 351 patients (38.5%). Patients with POAF were older (mean age 72.5 ± 10.3 years vs. 63.1 ± 14.1 years; p < 0.001) and more likely to have abnormal diastolic function. The rate of POAF increased exponentially with diastolic function grade (DFG) severity (p < 0.001). By multivariate analysis, after adjusting for clinical and surgical risk factors, independent predictors of POAF were older age (odds ratio [OR]: 1.05; p < 0.001), higher body mass index (OR: 1.06; p = 0.03), and abnormal LV DFG (DFG 1, OR: 5.12 [p = 0.006]; DFG 2, OR: 9.87 [p < 0.001]; and DFG 3, OR: 28.52 [p < 0.001]).</AbstractText>LV diastolic dysfunction is a powerful, independent predisposing substrate for the initiation of POAF. Evaluation may be useful during risk stratification of patients undergoing cardiac surgery.</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,928 | Effect of lenient versus strict rate control on cardiac remodeling in patients with atrial fibrillation data of the RACE II (RAte Control Efficacy in permanent atrial fibrillation II) study. | The aim of this study was to evaluate echocardiographic remodeling in permanent atrial fibrillation (AF) patients treated with either lenient or strict rate control.</AbstractText>It is unknown whether in permanent AF, lenient rate control is associated with more adverse cardiac remodeling than strict rate control.</AbstractText>Echocardiography was conducted at baseline and at follow-up in 517 patients included in the RACE II (RAte Control Efficacy in permanent atrial fibrillation II) trial. Echocardiographic parameters were compared between patients randomized to lenient rate control (n = 261) or strict rate control (n = 256).</AbstractText>Baseline echocardiographic parameters were comparable between patients randomized to lenient and strict rate control. Between baseline and follow-up, significant adverse atrial or ventricular remodeling was not observed in either group. There were also no significant differences in atrial and ventricular remodeling between patients who continuously had heart rates between 80 and 110 beats/min and patients who continuously had heart rates <80 beats/min during follow-up. Lenient rate control was not independently associated with changes in echocardiographic parameters: mean adjusted effect on left atrial size was 1.6 mm (p = 0.09) and 1.1 mm on left ventricular end-diastolic diameter (p = 0.23). Instead, female sex was independently associated with adverse remodeling: mean adjusted effect on left atrial size was 2.4 mm (p = 0.02) and 6.5 mm on left ventricular end-diastolic diameter (p < 0.0001).</AbstractText>Female sex, not lenient rate control, seemed to be associated with significant adverse cardiac remodeling in patients with permanent AF such as those enrolled in the RACE II study. (RAte Control Efficacy in Permanent Atrial Fibrillation [RACE II]; NCT00392613).</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,929 | Implantable cardioverter-defibrillator in a German shepherd dog with ventricular arrhythmias. | This report describes the use of an implantable cardioverter-defibrillator (ICD) in a young German shepherd dog afflicted with inherited ventricular arrhythmias. Proper generator and lead placement was necessary for successful termination of ventricular fibrillation during device testing at the time of implantation. The risks of inappropriate therapy triggered by sinus tachycardia and oversensing of the T wave were controlled by extensive programming of the device. Following spontaneous resolution of the arrhythmia and due to the development of sepsis associated with the device, the ICD was successfully removed. |
14,930 | Implications of pacemakers and implantable cardioverter defibrillators in urological practice. | Pacemakers and implantable cardioverter defibrillators are widely used and often encountered in urology practices worldwide. Safety and performance during electrosurgery, extracorporeal shock wave lithotripsy, magnetic resonance imaging, positron emission tomography and radiotherapy are not clearly defined. We reviewed the literature on their use and implications in urological practice.</AbstractText>We performed a PubMed® search and all relevant articles were studied to understand the basic functioning of these devices along with the technological advances designed to reduce electromagnetic interference.</AbstractText>A modern permanent pacemaker is comprised of a generator and leads connecting to the atrial or ventricular myocardium with sensing and pacing functions. Implantable cardioverter defibrillators respond to episodes of ventricular tachycardia and fibrillation by discharging a defibrillating current. From a device perspective, several protective mechanisms have been developed in the permanent pacemaker/implantable cardioverter defibrillator to reduce the effects of electromagnetic interference. These involve generator material changes, lead modification, and better sensing and pacing algorithms. Magnetic resonance imaging compatible pacemakers have now been developed and are approved for use in Europe. From a urologist's perspective 5 procedures require the close monitoring of permanent pacemaker/implantable cardioverter defibrillator function. 1) For electrosurgery modifications in the device and in the methods of use have been recommended. 2) For extracorporeal shock wave lithotripsy the European Association of Urology provides some guidance with regard to patients with these devices. 3) During positron emission tomography the pulse generator and the lead area should be covered with lead to protect the device. 4) Magnetic resonance imaging is contraindicated but currently trials are under way for a new pacing system for safe use in the magnetic resonance imaging environment. 5) Patients can undergo radiotherapy with standard precautions but those with an abdominal permanent pacemaker/implantable cardioverter defibrillator require careful planning. Finally, implanted devices should have a full evaluation before and after the procedure.</AbstractText>Clear guidelines are essential given the rapid advances in technology to enhance patient safety. Magnetic resonance imaging should be avoided in patients without a magnetic resonance imaging compatible device. However, patients can undergo extracorporeal shock wave lithotripsy, radiotherapy and positron emission tomography as long as the device is not in the path.</AbstractText>Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,931 | [Metabolic activity of neutrophilic granulocytes and possible ways of its correction in patients with acute coronary syndrome]. | The present study aimed to investigate the metabolic activity of neutrocytes and the action of corvitin on the level of superoxide anion and myeloperoxidases of cells in vitro with the calculation of index of consumption of myeloperoxidase in patients with ST-elevation acute coronary syndrome. Patient were divided into 2 groups according to the level of superoxide anion. Group 1 included the patients (68%) with the initially low level of superoxide anion, and adding of corvitin to the cells of such patients promoted normalization of this index. In this group we observed also neutrocytosis, low index of consumption of myeloperoxidase and a high level of this enzyme in general population of neutrocytes. Group 2 included patients (32%) with initially normal level of superoxide anion. In this group, corvitin did not influence substantially this factor. Such patients had a level ofmyeloperoxidase within control values and the index of consumption of this enzyme was also within control values. The analysis of hospital period showed that the patients of group 1 had a higher frequency of ventricular tachycardia/ventricular fibrillation, paroxysms of atrial fibrillation, bundle-branch blocks and worsening of the kidney function. We suppose that a low level of superoxide anion in neutrocytes play a major role in the development of complications in patients with acute coronary syndrome. An intravenous administration of corvitin was effective in restoring the metabolic activity of neutrocytes. |
14,932 | Prevalence and characteristics of idiopathic right ventricular outflow tract arrhythmias associated with J-waves. | The arrhythmogenic relationship between the presence of J-waves during sinus rhythm and idiopathic ventricular tachycardia (VT) or pre-mature ventricular contractions (PVCs) originating from the right ventricular outflow tract (RVOT) has not been reported. The aim of this study was to investigate the prevalence and characteristics of idiopathic RVOT-VT/PVCs associated with J-waves.</AbstractText>The study enrolled 138 consecutive idiopathic RVOT-VT/PVC patients undergoing radiofrequency catheter ablation (RFCA) and 276 age- and gender-matched control subjects. The prevalence of J-waves was assessed in each cohort, and the clinical and electrophysiological data were compared between the RVOT-VT/PVC patients with J-waves (J-RVOT-VT/PVC group) and those without (non-J-RVOT-VT/PVC group). J-waves were more common among patients with idiopathic RVOT-VT/PVCs than among the matched control subjects (40 vs. 16% P < 0.001). The J-RVOT-VT/PVC group had a higher incidence of sustained VT (25 vs. 5%, P < 0.01), shorter VT cycle length (302 ± 57 vs. 351 ± 58 ms, P < 0.001), and more episodes of syncope (25 vs. 2%, P < 0.001) than did the non-J-RVOT-VT/PVC group. However, no patients demonstrated any ventricular fibrillation (VF) or cardiac sudden death in either group.</AbstractText>There was a high prevalence of J-waves in the idiopathic RVOT-VT/PVC patients referred for RFCA. Although patients with idiopathic RVOT arrhythmias associated with J-waves might have a more enhanced arrhythmogenicity than those without J-waves, the significance of those J-waves was limited in terms of the prognosis and VF.</AbstractText> |
14,933 | Pacing the right ventricular outflow tract septum: time to embrace the future. | Transvenous pacing has revolutionized the management of patients with potentially life-threatening bradycardias and at its most basic level ensures rate support to maintain cardiac output. However, we have known for at least a decade that pacing from the right ventricle (RV) apex can induce left ventricle (LV) dysfunction, atrial fibrillation, heart failure, and maybe an increased mortality. Although pacemaker manufacturers have developed successful pacing algorithms designed to minimize unnecessary ventricular pacing, it cannot be avoided in a substantial proportion of pacemaker-dependent patients. Just as there is undoubted evidence that RV apical pacing is injurious, there is emerging evidence that pacing from the RV septum is associated with a shorter duration of activation, improved haemodynamics, and less LV remodelling. The move from traditional RV apical pacing to RV septal pacing requires a change in mindset for many practitioners. The anatomical landmarks and electrocardiograph features of RV septal pacing are well described and easily recognized. While active fixation is required to place the lead on the septum, shaped stylets are now available to assist the implanter. In addition, concerns about the stability and longevity of steroid-eluting active fixation leads have proven to be unfounded. We therefore encourage all implanters to adopt RV septal pacing to minimize the potential of harm to their patients. |
14,934 | Ventricular fibrillation in loop recorder memories in a patient with early repolarization syndrome. | We report the first documentation of spontaneous ventricular fibrillation by a loop recorder in a patient with an ECG pattern of early repolarization (ER) in the inferior leads and presenting with syncope. |
14,935 | Drug monitoring of a case of citalopram overdosage. | Selective serotonin reuptake inhibitors are widely prescribed drugs without recognized cardiovascular risk. We report the case of a 54-year-old patient who developed QTc interval prolongation, followed by ventricular fibrillation episodes, 10 hours after admission to the ICU, in the setting of a citalopram overdose. Citalopram plasma values dropped from 5.88 to 0.34 mg/L at 9 days postadmission. The patient was treated by oral activated charcoal, and final outcome was favorable. |
14,936 | Human ventricular fibrillation during global ischemia and reperfusion: paradoxical changes in activation rate and wavefront complexity. | Ischemic ventricular fibrillation in experimental models has been shown to progress through a series of stages. Progression of ischemic VF in the in vivo human heart has not been determined.</AbstractText>We studied 10 patients undergoing cardiac surgery. Ventricular fibrillation was induced by burst pacing. After 30 seconds, global myocardial ischemia was induced by aortic cross-clamp and maintained for 2.5 minutes, followed by coronary reflow. Epicardial activity was sampled (1 kHz) with a sock that contained 256 unipolar contact electrodes. Dominant frequencies were calculated with a fast Fourier transform with a moving window. The locations of phase singularities and activation wavefronts were identified at 10-ms intervals. Preischemic (perfused) ventricular fibrillation was maintained by a disorganized mix of large and small wavefronts. During global myocardial ischemia, mean dominant frequencies decreased from 6.4 to 4.7 Hz at a rate of -0.011±0.002 Hz s(-1) (P<0.001) and then increased rapidly to 7.4 Hz within 30 seconds of reflow. In contrast, the average number of epicardial phase singularities increased during ischemia from 7.7 to 9.7 at a rate of 0.013±0.005 phase singularities per second (P<0.01) and remained unchanged during reflow, at 10.3. The number of wavefronts showed a similar time course to the number of phase singularities.</AbstractText>In human ventricular fibrillation, we found an increase in complexity of electric activation patterns during global myocardial ischemia, and this was not reversed during reflow despite an increase in activation rate.</AbstractText> |
14,937 | Defibrillation testing during implantable cardioverter-defibrillator implantation in Italian current practice: the Assessment of Long-term Induction clinical ValuE (ALIVE) project. | Clinical practice with regard to defibrillation threshold (DFT) testing during implantable cardioverter-defibrillator (ICD) implantation varies considerably, even among experienced implanting centers. International guidelines do not as yet mandate DFT testing.</AbstractText>The objective of this project is to assess current clinical decision making regarding DFT testing during ICD implantation.</AbstractText>The ALIVE project collected data on DFT testing from a multicenter network of Italian clinicians sharing a common system for the collection, management, analysis, and reporting of clinical and diagnostic data from patients with Medtronic (Minneapolis, MN) implantable devices.</AbstractText>Data on 2,082 consecutive patients implanted with a Medtronic ICD in 111 Italian centers, over the period 2007 to 2010, were analyzed. Defibrillation threshold testing was performed in 33% of cases (678/2,082). The main reasons for performing the test were physician's clinical practice ("I always perform DFT") (80%) and secondary prevention implantation (12%). The main reasons for not performing DFT testing were centers' practice (44%), primary prevention (31%), and device replacement (15%). In 22 patients, ventricular fibrillation induction was not achieved; 656 patients completed DFT testing: 633 patients (96%) performed a single test, 19 patients (3%) performed a second induction test, and 4 patients (0.6%) underwent an additional induction test.</AbstractText>The preliminary results of the ALIVE project show that a great number of implant procedures are performed without DFT testing in the common practice of the participating centers. We also measured an inhomogeneous, center-dependent DFT testing behavior, which suggests the importance of defining a common guideline for ICD implant testing. Follow-up data on our patients will provide more information on the clinical value of the test.</AbstractText>Copyright © 2011 Mosby, Inc. All rights reserved.</CopyrightInformation> |
14,938 | Clinical characteristics of patients with asymptomatic recurrences of atrial fibrillation in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico-Atrial Fibrillation (GISSI-AF) trial. | Atrial fibrillation (AF) is a common arrhythmia that frequently recurs after restoration of sinus rhythm. In a consistent percentage of cases, AF recurrences are asymptomatic, thus making its clinical management difficult in relation to both therapeutic efficacy and thromboembolic risk.</AbstractText>The GISSI-AF trial enrolled 1,442 patients in sinus rhythm with previous AF episodes. Patients were randomized to valsartan or placebo and followed for 12 months. To improve the likelihood of detecting arrhythmic recurrences, arrhythmic follow-up was based on both programmed or symptom-related control visits and transtelephonic electrocardiographic transmissions. The present post hoc analysis was performed on 1,638 arrhythmic episodes that occurred in 623 patients.</AbstractText>Asymptomatic AF recurrences were present in 49.5% of patients. In multivariable analysis, asymptomatic AF recurrences were significantly associated with a longer duration of qualifying arrhythmias (odds ratio [95% CI] 1.57 (1.26-1.97), P < .0001). A lower ventricular response (P < .001) and a longer duration of the arrhythmic recurrence (P < .001) characterized asymptomatic episodes. Patients with asymptomatic events were more likely to be in AF at the time of electrocardiographic control at the end of the 12-month follow-up (adjusted odds ratio [95% CI] 4.9 (2.8-8.4), P < .001). Moreover, a higher CHADS(2) (Congestive heart failure, history of Hypertension, Age≥75 years, Diabetes mellitus, and past history of Stroke or TIA doubled) score and a more frequent use of amiodarone, calcium-channel blockers, and digitalis characterized patients with asymptomatic, whereas 1C drugs were more often used in subjects with symptomatic recurrences.</AbstractText>Asymptomatic AF recurrences were frequent in the GISSI-AF study population in patients who were more likely to develop persistent-permanent AF and were characterized by an increased thromboembolic risk.</AbstractText>Copyright © 2011 Mosby, Inc. All rights reserved.</CopyrightInformation> |
14,939 | The impact of atrial fibrillation with rapid ventricular rates and device programming on shocks in 106,513 ICD and CRT-D patients. | The relationship between shocks, device programming, and atrial fibrillation (AF) with a rapid ventricular rate (AF + RVR) using continuous daily monitoring has not been studied in large number of patients with implantable cardioverter-defibrillators (ICDs).</AbstractText>The aim of this analysis was to determine the impact of ICD programming and ventricular rate control during AF on ICD shocks.</AbstractText>An observational cohort analysis was performed with dual-chamber ICD and cardiac resynchronization therapy-defibrillator devices. The primary endpoint was spontaneous all-cause shocked episodes per 100 patient-years. Shock reduction programming strategies were entered into a multivariable model including slowest ventricular tachycardia/ventricular fibrillation (VT/VF) detection threshold, number of intervals to detect VF (NID), supraventricular tachycardia (SVT) discriminators ON, antitachycardia pacing (ATP) ON for fast VTs (FVTs) and AF + RVR (AF ≥1 hour for ≥1 day with average ≥110 beats per minute). We also characterized the predictive ability of AF + RVR to identify patients at risk of subsequent shocks.</AbstractText>There were 106,513 patients at 2858 institutions, with 2.5 ± 1.4 years of follow-up, 75% being male, age 67 ± 12 years, 59% with dual-chamber ICDs, and 11% with AF + RVR. A total of 22,062 patients (21%) received 82,396 shocks. After adjusting for all variables, AF + RVR, slower VT/VF detection threshold, and shorter VF NID were found to be associated with more shocks (P < .05 for all). Continuous monitoring of AF + RVR identified patients at up to 5-fold increased risk of shocks.</AbstractText>Faster VT/VF detection thresholds, longer detection durations, use of SVT discriminators, and delivery of ATP reduces all-cause ICD shocks. Continuous monitoring of AF + RVR identifies patients at the highest risk of future ICD shocks.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,940 | Feasibility of initiating extracorporeal life support during mechanical chest compression CPR: a porcine pilot study. | Recently, portable extracorporeal membrane oxygenation (ECMO) machines have become commercially available. This creates the potential to utilize extracorporeal life support (ECLS) for the treatment of sudden cardiac arrest in the emergency department, and potentially in the out-of-hospital setting.</AbstractText>We sought to determine the feasibility of installing the ECMO circuit during delivery of mechanical chest compression CPR.</AbstractText>We used 5 mixed-breed domestic swine with a mean mass of 26.0 kg. After induction of anesthesia, animals were instrumented with micromanometer-tipped transducers placed in the aorta and right atrium via the left femoral artery and vein. Ventricular fibrillation (VF) was induced electrically with a transthoracic shock and left untreated for 8 min. Then, mechanical chest compressions were begun (LUCAS, Jolife, Lund, Sweden) and manual ventilations were performed to maintain ETCO(2) between 35 and 45Torr. Compressions continued until ECMO flow was started. Ten minutes after induction of VF, drugs were given (epinephrine, vasopressin, and propranolol). ECMO installation was started via cutdown on the right external jugular vein and right femoral artery for placement of venous and arterial catheters while chest compressions continued. ECMO installation start time varied from 17 to 30 min after start of compressions and continued until ECG indicated a shockable rhythm. First rescue shocks were given at 22, 32, 35, 44, and 65 min.</AbstractText>ECMO was successfully installed in all five animals without incident. It was necessary to briefly discontinue chest compressions during the most delicate part of inserting the catheters into the vessels. ECMO also allowed for very rapid cooling of the animals and facilitated post-resuscitation hemodynamic support. Only the 65-min animal did not attain return of spontaneous circulation (ROSC).</AbstractText>Mechanical chest compression may be a suitable therapeutic bridge to the installation of ECMO and does not interfere with ECMO catheter placement.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,941 | Graves' disease complicated by ventricular fibrillation in three men who were smokers. | Thyrotoxicosis is known to be associated with sinus tachycardia and supraventricular tachyarrhythmias, but rarely with ventricular fibrillation (Vf), which has only occurred in some patients with hypokalemic periodic paralysis or ischemic heart disease.</AbstractText>We present three men who were transferred to our hospital with Graves' disease who developed idiopathic Vf. None of them had hypokalemic periodic paralysis or ischemic heart disease but all were smokers. None of other patients with thyrotoxicosis (587 females and 155 males) who were seen at our hospital, in the period during which the three men were seen, had idiopathic Vf. In our three men with thyrotoxicosis and idiopathic Vf, there was no identifiable underlying heart disease. One of the three patients died of hypoxic encephalopathy. The other two men did not have recurrent Vf after their thyroid function normalized.</AbstractText>These cases and a review of similar cases in the literature imply that improving thyrotoxicosis seems to be effective for treating idiopathic Vf in some patients.</AbstractText>Our findings suggest that thyroid hormone excess might play a direct role in the development of Vf in susceptible individuals. Our experience with these three patients suggests that smoking men with thyrotoxicosis likely have an increased risk for Vf, even if they do not have other predisposing factors.</AbstractText> |
14,942 | ECG repolarization syndrome abnormalities (J wave syndromes) and idiopathic ventricular fibrillation: diagnostic and management. | Early repolarization (ER) pattern has been recognized for several decades and was interpreted as a variant of the normal electrocardiogram (ECG) as it was frequently observed in young healthy subjects or athletes. It is characterized by a J point elevation and ST-segment elevation inscribed as a QRS slurring or a notch of the S wave in the inferior leads or/and the lateral leads. The ER pattern has been the subject of increased interest since the report of its higher prevalence in subjects resuscitated from cardiac arrest related to idiopathic ventricular fibrillation (VF). Furthermore, population-based studies showed in healthy young adults that ER pattern was associated with an increased cardiovascular mortality and total mortality. A relationship between ER pattern and malignant arrhythmias is also supported by the experimental work of Antzelevitch et al. which provided the cellular and ionic basis for the J point elevation and its arrhythmogenic potential. The ER pattern may coexist with a number of cardiac or extracardiac conditions such as hypothermia. But this review will focus attention on the "isolated ER pattern" in healthy individuals. Antzelevitch and Yan proposed because of a number of similarities between the "ER syndrome" and the Brugada syndrome to group both syndromes under the heading of "J wave syndromes". The management of ER syndrome (associated with idiopathic VF) is clearly the insertion of an implantable cardioverter defibrillator (ICD). The ER pattern associated with symptoms such as syncope or a familial history of sudden cardiac death requires a complete work-up. Caution should be raised not to generate anxiety in the subject with asymptomatic "isolated ER pattern" as the odds of developing malignant ventricular arrhythmias or to suffer sudden death in this case are extremely low. |
14,943 | Role of oral amiodarone in patients with atrial fibrillation and congestive heart failure. | Amiodarone is recognized as the most effective therapy for maintaining sinus rhythm (SR) post cardioversion in patients with atrial fibrillation (AF). It is also recommended for controlling AF in patients with congestive heart failure (CHF). We retrospectively examined the efficacy and safety of oral amiodarone in patients with AF and CHF.</AbstractText>Forty-eight consecutive AF patients whose left ventricular ejection fraction (LVEF) was less than 50% and B-type natriuretic peptide (BNP) was higher than 100 pg/ml were investigated retrospectively, and divided into 3 groups: paroxysmal AF, 16 patients; persistent AF, 9 patients; and permanent AF, 23 patients.</AbstractText>The permanent AF group had a longer history of AF, larger left ventricular end-diastolic diameter (LVDd) and left atrial diameter (LAD) than paroxysmal and persistent AF groups (p<0.05). After median follow-up of 265 days, amiodarone suppressed paroxysms in 88% of paroxysmal AF patients, while SR was maintained in all persistent AF patients, and 35% of permanent AF patients. Of the 32 persistent and permanent AF patients, 12 (71%) out of 17 maintained SR after successful electrical cardioversion, and conversion to SR occurred spontaneously in 5 (33%) out of 15. The effective group had significantly smaller LVDd and LAD than the ineffective group. In the effective group, BNP decreased significantly from 723±566 pg/ml to 248±252 pg/ml, (p<0.0005) and LVEF increased significantly from 33±7% to 50±13% (p<0.0005) during follow up, while no changes were observed in the ineffective group. The patients with low LVEF (≤30%) benefited comparably from amiodarone to the patients with LVEF >30%. Complications occurred in 24 (50%) patients leading to discontinuation of amiodarone in 11 (23%).</AbstractText>Oral amiodarone helped restore SR in paroxysmal and persistent AF patients with CHF. The successful rhythm control by amiodarone resulted in the improvement of LV function and the decrease of BNP levels.</AbstractText>Copyright © 2011 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
14,944 | Incidence of various cardiac arrhythmias and conduction disturbances due to high dose intravenous methylprednisolone in patients with multiple sclerosis. | High-dose intravenous methylprednisolone is the most common therapeutic modality to treat acute exacerbations in multiple sclerosis (MS). Various cardiac arrhythmias have been reported during corticosteroid pulse therapy. This study was conducted to detect cardiac rhythm changes in patients with MS while receiving high dose methylprednisolone.</AbstractText>We enrolled 52 consecutive MS patients with acute relapse to perform cardiac monitoring 4h before, during and 18 h after infusion of 1000 mg intravenous (IV) methylprednisolone.</AbstractText>Sinus tachycardia was the most common change in cardiac rhythms before, during, and after corticosteroid pulse therapy. Up to 41.9% of the patients, developed sinus bradycardia after pulse infusion. Sinus arrest and sinus exit block were observed in 12 patients. Atrial fibrillation and ventricular tachycardia were observed in three patients and one patient, respectively. The most important cardiac arrhythmias including ventricular tachycardia, sinus arrest, and sinus exit block, were correlated with smoking and more commonly observed during 12h post infusion. Sinus bradycardia and atrial fibrillation were detected more commonly in patients with history of urinary dysfunction.</AbstractText>High dose intravenous prednisolone might cause different types of arrhythmias in MS patients. Cigarette smokers and patients with autonomic disturbances like sphincter and bowel problems have more chance to develop arrhythmias while receiving high dose steroids.</AbstractText>Copyright © 2011 Elsevier B.V. All rights reserved.</CopyrightInformation> |
14,945 | A case of ventricular asystole without escape rhythm 4 days after percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy with drug-resistant paroxysmal atrial fibrillation. | A 42-year-old man with a more than 10-year history of hypertrophic obstructive cardiomyopathy, but no history of heart failure or syncope, had left ventricular outflow tract pressure gradient (LVOT-PG) of 50-80 mmHg on Doppler echocardiography. In June 2010, he experienced general malaise on effort, and LVOT-PG increased to 124 mmHg. Two months later, he suffered a transient ischemic attack, complicated with atrial fibrillation (AF). He underwent cardiac defibrillation and was prescribed amiodarone, but the arrhythmia recurred easily. Therefore, percutaneous transluminal septal myocardial ablation (PTSMA) was performed to prevent AF. The procedure entailed transient complete atrioventricular block (CAVB), which was resolved after a few hours. Four days later, CAVB recurred and advanced to fatal ventricular asystole without escape rhythm. The patient was resuscitated instantaneously and recovered without brain damage. Finally, a DDD permanent pacemaker was implanted 10 days after the procedure. Except for conduction problems, his cardiac condition was good after PTSMA, as paroxysmal AF disappeared and LVOT-PG was markedly decreased. CAVB is a well-known complication of PTSMA, but fatal ventricular asystole several days after the procedure is rare. Intensive care is required after PTSMA implementation. |
14,946 | Generation of realistic atrial to atrial interval series during atrial fibrillation. | The aim of the this study is to describe a methodological architecture for the generation of realistic atrial to atrial activation intervals (AA) during atrial fibrillation (AF), which can be used to investigate the role of the fibrillatory process in the ventricular response during AF. In this study, a methodology for the generation of AA interval series with a desired probability density function and autocorrelation function is presented. The methodology was evaluated on 2000 AA interval series from 20 endocardial recordings. The results showed that synthetic AA series presented the same statistical characteristics as the real AA series, with a correlation higher than 0.94 (P < 0.01) for all measured statistical parameters. In addition, the role of each statistical characteristic of the AA interval series in the ventricular response during AF is examined using a mathematical model of the atrioventricular node. The statistical characteristics of the AA series influenced the position of more probable RR intervals and the shape of the RR histogram, demonstrating the importance of an accurate characterization and generation of AA interval series during AF. The use of the present methodology may help in understanding the role of the atrial fibrillatory process in the ventricular response during AF. |
14,947 | Long-term efficacy of amiodarone therapy for the prevention of recurrence of paroxysmal atrial fibrillation. Analysis based on patient characteristics. | There is little information available on factors affecting the long-term prevention of paroxysmal atrial fibrillation (AF) in the Japanese population. A total of 71 patients (49 men, mean age, 68 ± 8 years) with paroxysmal AF refractory to ≥ 2 class I antiarrhythmic drugs received oral amiodarone (50-200 mg/day). All patients were observed for more than 12 months (mean follow-up period, 47 ± 26 months) and were analyzed on the basis of patient profiles. The percentage of patients with AF recurrence despite amiodarone therapy was 54% in all patients. In multivariate logistic regression analysis adjusted for age and sex, the following factors were associated with preventive efficacy for AF recurrence: left ventricular ejection fraction (LVEF) (relative risk [RR] 0.933, 95% confidence interval [CI] 0.877-0.993, P = 0.029), asymptomatic AF (RR 0.068, CI 0.005-0.870, P = 0.039), and AF occurring irrespective of circadian variation (RR 0.115, CI 0.013-0.988, P = 0.049). The percentage of patients with conversion to permanent AF despite amiodarone therapy was 31% in all patients. In multivariate logistic regression analysis adjusted for age and sex, asymptomatic AF (RR 0.085, CI 0.010-0.732, P = 0.025) was the only factor associated with preventive efficacy for conversion to permanent AF. Amiodarone appears to be effective in maintaining sinus rhythm, especially in patients with impaired left ventricular function. In contrast, amiodarone appears to be refractory in those with asymptomatic AF or AF occurring irrespective of circadian variation. |
14,948 | Decay in chest compression quality due to fatigue is rare during prolonged advanced life support in a manikin model. | The aim of this study was to measure chest compression decay during simulated advanced life support (ALS) in a cardiac arrest manikin model.</AbstractText>19 paramedic teams, each consisting of three paramedics, performed ALS for 12 minutes with the same paramedic providing all chest compressions. The patient was a resuscitation manikin found in ventricular fibrillation (VF). The first shock terminated the VF and the patient remained in pulseless electrical activity (PEA) throughout the scenario. Average chest compression depth and rate was measured each minute for 12 minutes and divided into three groups based on chest compression quality; good (compression depth ≥ 40 mm, compression rate 100-120/minute for each minute of CPR), bad (initial compression depth < 40 mm, initial compression rate < 100 or > 120/minute) or decay (change from good to bad during the 12 minutes). Changes in no-flow ratio (NFR, defined as the time without chest compressions divided by the total time of the ALS scenario) over time was also measured.</AbstractText>Based on compression depth, 5 (26%), 9 (47%) and 5 (26%) were good, bad and with decay, respectively. Only one paramedic experienced decay within the first two minutes. Based on compression rate, 6 (32%), 6 (32%) and 7 (37%) were good, bad and with decay, respectively. NFR was 22% in both the 1-3 and 4-6 minute periods, respectively, but decreased to 14% in the 7-9 minute period (P = 0.002) and to 10% in the 10-12 minute period (P < 0.001).</AbstractText>In this simulated cardiac arrest manikin study, only half of the providers achieved guideline recommended compression depth during prolonged ALS. Large inter-individual differences in chest compression quality were already present from the initiation of CPR. Chest compression decay and thereby fatigue within the first two minutes was rare.</AbstractText> |
14,949 | Biophysical properties and functional consequences of reactive oxygen species (ROS)-induced ROS release in intact myocardium. | Reactive oxygen species (ROS)-induced ROS release (RIRR) is a fundamental mechanism by which cardiac mitochondria respond to elevated ROS levels by stimulating endogenous ROS production in a regenerative, autocatalytic process that ultimately results in global oxidative stress (OS), cellular dysfunction and death. Despite elegant studies describing the phenomenon of RIRR under artificial conditions such as photo-induced oxidation of discrete regions within cardiomyocytes, the existence, biophysical properties and functional consequences of RIRR in intact myocardium remain unclear. Here, we used a semi-quantitative approach of optical superoxide (O(2)(-)) mapping using dihydroethidium (DHE) fluorescence to explore RIRR, its arrhythmic consequences and underlying mechanisms in intact myocardium. Initially, perfusion of rat hearts with 200 μM H(2)O(2) for 40 min (n = 4) elicited two distinct O(2)(-) peaks that were readily distinguished by their timing and amplitude. The first peak (P1), which was generated rapidly (within 5-8 min of H(2)O(2) perfusion) was associated with a relatively limited (10 ± 2%) rise in normalized O(2)(-) levels relative to baseline. In contrast, the second peak (P2) occurred 19-26 min following onset of H(2)O(2) perfusion and was associated with a significantly greater amplitude compared to P1. Spatio-temporal ROS mapping during P2 revealed active O(2)(-) propagation across the myocardium at a velocity of ~20 μm s(-1). Exposure of hearts (n = 18) to a short (10 min) episode of H(2)O(2) perfusion revealed consistent generation of P2 by high (≥200 μM, 8/8) but not lower (≤100 μM, 3/8) H(2)O(2) concentrations (P < 0.03). In these hearts, onset of P2 occurred following, not during, the 10 min OS protocol, consistent with RIRR. Importantly, P2 (+) hearts exhibited a markedly greater (by 3.8-fold, P < 0.001) arrhythmia score compared to P2 (-) hearts. To explore the mechanism underlying RIRR in intact myocardium, hearts were perfused with either cyclosporin A (CsA) or 4-chlorodiazepam (4-Cl-DZP) to inhibit the mitochondrial permeability transition pore (mPTP) or the inner membrane anion channel (IMAC), respectively. Surprisingly, perfusion with CsA failed to suppress (P = 0.75, n.s.) or even delay H(2)O(2)-induced P2 or the incidence of arrhythmias compared to untreated hearts. In sharp contrast, perfusion with 4-Cl-DZP markedly blunted O(2)(-) levels during P2, and suppressed the incidence of sustained ventricular tachycardia or ventricular fibrillation (VT/VF). Finally, perfusion of hearts with the synthetic superoxide dismutase/catalase mimetic EUK-134 completely abolished the H(2)O(2)-mediated RIRR response as well as the incidence of arrhythmias. These findings extend the concept of RIRR to the level of the intact heart, establish regenerative O(2)(-) production as the mediator of RIRR-related arrhythmias and reveal their strong dependence on IMAC and not the mPTP in this acute model of OS. |
14,950 | Striking In vivo phenotype of a disease-associated human SCN5A mutation producing minimal changes in vitro. | The D1275N SCN5A mutation has been associated with a range of unusual phenotypes, including conduction disease and dilated cardiomyopathy, as well as atrial and ventricular tachyarrhythmias. However, when D1275N is studied in heterologous expression systems, most studies show near-normal sodium channel function. Thus, the relationship of the variant to the clinical phenotypes remains uncertain.</AbstractText>We identified D1275N in a patient with atrial flutter, atrial standstill, conduction disease, and sinus node dysfunction. There was no major difference in biophysical properties between wild-type and D1275N channels expressed in Chinese hamster ovary cells or tsA201 cells in the absence or presence of β1 subunits. To determine D1275N function in vivo, the Scn5a locus was modified to knock out the mouse gene, and the full-length wild-type (H) or D1275N (DN) human SCN5A cDNAs were then inserted at the modified locus by recombinase mediated cassette exchange. Mice carrying the DN allele displayed slow conduction, heart block, atrial fibrillation, ventricular tachycardia, and a dilated cardiomyopathy phenotype, with no significant fibrosis or myocyte disarray on histological examination. The DN allele conferred gene-dose-dependent increases in SCN5A mRNA abundance but reduced sodium channel protein abundance and peak sodium current amplitudes (H/H, 41.0±2.9 pA/pF at -30 mV; DN/H, 19.2±3.1 pA/pF, P<0.001 vs. H/H; DN/DN, 9.3±1.1 pA/pF, P<0.001 versus H/H).</AbstractText>Although D1275N produces near-normal currents in multiple heterologous expression experiments, our data establish this variant as a pathological mutation that generates conduction slowing, arrhythmias, and a dilated cardiomyopathy phenotype by reducing cardiac sodium current.</AbstractText> |
14,951 | Left atrial thrombus and prognosis after anticoagulation therapy in patients with atrial fibrillation. | Anticoagulation therapy reduces the risk of thromboembolic events by two-thirds in patients with atrial fibrillation (AF). The prevalence of left atrial thrombus (LAT) in AF patients with anticoagulation therapy has not been fully investigated.</AbstractText>To investigate the prevalence of LAT and its impact on the outcomes in patients with nonvalvular AF after anticoagulation therapy.</AbstractText>This study consisted of 231 patients with nonvalvular AF who had transthoracic (TTE) and transesophageal echocardiographic (TEE) examinations more than 3 weeks after anticoagulation therapy. The clinical and echocardiographic characteristics were evaluated.</AbstractText>LAT was observed in 13 (8.8%) of 148 patients with sub-therapeutic anticoagulation, and in 3 (3.6%) of 83 patients with sufficient anticoagulation. The presence of LAT was associated with higher CHADS(2) score, decreased LA volume changes and the presence of spontaneous echocardiographic contrast (SEC) in patients with sub-therapeutic anticoagulation. Patients with LAT after sufficient anticoagulation were male with permanent AF who had decreased left ventricular systolic and diastolic function and dilated LA on TTE and SEC, and reduced appendage flow velocity on TEE. Patients with LAT had worse cardiovascular outcomes compared with those without LAT (p=0.02).</AbstractText>We demonstrated that LAT was a univariate risk factor associated with worse cardiovascular outcomes, which was observed in 8.8% of patients with sub-therapeutic anticoagulation and 3.6% of patients with sufficient anticoagulation.</AbstractText>Copyright © 2011 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
14,952 | Manifestation of Long QT syndrome with normal QTc interval under anesthesia: a case report. | Patients with congenital Long QT are known to have normal QT interval in symptom-free period and in the early years of life. Precipitating factors like surgical stress, interactions with anesthetic agents prolonging QT interval, and electrolyte imbalances can manifest with life threatening arrhythmias in congenital or acquired Long QT syndrome. We report a case of concealed LQTS manifesting under anesthesia and its subsequent perioperative course. |
14,953 | Cardiovascular events in thyroid disease: a population based, prospective study. | No consensus exists whether subclinical thyroid disease should be treated or just observed. Untreated overt thyroid disease is associated with increased risk of cardiovascular disease, and this study was conducted to assess the risk of cardiovascular events in subclinical thyroid disease. The population-based prospective study was conducted in Denmark. A total of 609 subjects from general practice aged 50 years or above with normal left ventricular function were examined. During a median of 5 years of follow-up, major cardiovascular events were documented. In subjects with abnormal TSH at baseline, information about potential thyroid treatment during follow-up was obtained from case reports and mailings. At baseline, 549 (90.7%) were euthyroid (TSH 0.40-4.00 mU/l), 31 (5.1%) were subclinical hypothyroid (TSH>4.00 mU/l), and 25 (4.1%) were subclinical hyperthyroid (TSH<0.40 mU/l). 1 overt hyperthyroid and 3 overt hypothyroid participants were excluded from the analyses. At baseline, the levels of NT-proBNP were inversely associated with the levels of TSH; the lower the levels of TSH, the higher the NT-proBNP concentration. During follow-up, 88 participants died, 81 had a major cardiovascular event, and 28 had a stroke. The incidence of stroke was increased among subjects with subclinical hyperthyroidism, HR 3.39 (95% CI 1.15-10.00, p=0.027) after adjusting for sex, age, and atrial fibrillation. Subclinical hypothyroidism was not related with any of the outcome measurements. Subclinical hyperthyroidism seems to be a risk factor of developing major cardiovascular events, especially stroke in older adults from the general population with normal left ventricular function. |
14,954 | The survival of patients with heart failure with preserved or reduced left ventricular ejection fraction: an individual patient data meta-analysis. | A substantial proportion of patients with heart failure have preserved left ventricular ejection fraction (HF-PEF). Previous studies have reported mixed results whether survival is similar to those patients with heart failure and reduced EF (HF-REF).</AbstractText>We compared survival in patients with HF-PEF with that in patients with HF-REF in a meta-analysis using individual patient data. Preserved EF was defined as an EF ≥ 50%. The 31 studies included 41 972 patients: 10 347 with HF-PEF and 31 625 with HF-REF. Compared with patients with HF-REF, those with HF-PEF were older (mean age 71 vs. 66 years), were more often women (50 vs. 28%), and have a history of hypertension (51 vs. 41%). Ischaemic aetiology was less common (43 vs. 59%) in patients with HF-PEF. There were 121 [95% confidence interval (CI): 117, 126] deaths per 1000 patient-years in those with HF-PEF and 141 (95% CI: 138, 144) deaths per 1000 patient-years in those with HF-REF. Patients with HF-PEF had lower mortality than those with HF-REF (adjusted for age, gender, aetiology, and history of hypertension, diabetes, and atrial fibrillation); hazard ratio 0.68 (95% CI: 0.64, 0.71). The risk of death did not increase notably until EF fell below 40%.</AbstractText>Patients with HF-PEF have a lower risk of death than patients with HF-REF, and this difference is seen regardless of age, gender, and aetiology of HF. However, absolute mortality is still high in patients with HF-PEF highlighting the need for a treatment to improve prognosis.</AbstractText> |
14,955 | Mechanisms of atrial-selective block of Na⁺ channels by ranolazine: I. Experimental analysis of the use-dependent block. | Atrial-selective inhibition of cardiac Na(+) channel current (I(Na)) and I(Na)-dependent parameters has been shown to contribute to the safe and effective management of atrial fibrillation. The present study examined the basis for the atrial-selective actions of ranolazine. Whole cell I(Na) was recorded at 15°C in canine atrial and ventricular myocytes and in human embryonic kidney (HEK)-293 cells expressing SCN5A. Tonic block was negligible at holding potentials from -140 to -100 mV, suggesting minimal drug interactions with the closed state. Trains of 40 pulses were elicited over a range of holding potentials to determine use-dependent block. Guarded receptor formalism was used to analyze the development of block during pulse trains. Use-dependent block by ranolazine increased at more depolarized holding potentials, consistent with an interaction of the drug with either preopen or inactivated states, but was unaffected by longer pulse durations between 5 and 200 ms, suggesting a weak interaction with the inactivated state. Block was significantly increased at shorter diastolic intervals between 20 and 200 ms. Responses in atrial and ventricular myocytes and in HEK-293 cells displayed a similar pattern. Ranolazine is an open state blocker that unbinds from closed Na(+) channels unusually fast but is trapped in the inactivated state. Kinetic rates of ranolazine interactions with different states of atrial and ventricular Na(+) channels were similar. Our data suggest that the atrial selectivity of ranolazine is due to a more negative steady-state inactivation curve, less negative resting membrane potential, and shorter diastolic intervals in atrial cells compared with ventricular cells at rapid rates. |
14,956 | In-hospital use of automated external defibrillators does not improve survival. | The use of automated external defibrillators (AEDs) following a cardiac arrest in the out-of-hospital setting has demonstrated increased survival rates, likely because up to 71% of out-of-hospital cardiac arrests are associated with rhythm disturbances that are able to be treated with defibrillation. It is less clear whether the use of AEDs in the hospital setting would be effective because fewer patients (approximately 25%) have initial cardiac rhythms that respond to defibrillation and because survival may be compromised if the use of AEDs contributes to interruptions in the delivery of chest compressions.</AbstractText>The authors of this study used data from the National Registry of Cardiopulmonary Resuscitation (NRCPR) to evaluate the association between survival after an in-hospital cardiac arrest and use of an AED. Data was drawn from patients 18 years of age or older, who had an index pulseless, in-hospital cardiac arrest in clinical area where an AED was available for patient treatment. The sample comprised 11,695 patients from 204 hospitals. The primary outcome measure was survival to hospital discharge. The authors also reported secondary outcomes such as return of spontaneous circulation (ROSC) for at least 20 min during the acute resuscitation; survival at 24h; and neurological status among those patients surviving to hospital discharge.</AbstractText>Of the 11,695 patients with cardiac arrests, the majority (82.2%; n=9616) were in a nonshockable rhythm, such as asystole or pulseless electrical activity (PEA). Only 17.8% (n=2079) of patients in the study were in a shockable rhythm (ventricular fibrillation and pulseless ventricular tachycardia). AEDs were used on 4515 patients (38.6%). An overall survival to discharge rate of 18.1% (n=2117) was reported. The use of an AED was associated with lower survival rates (16.3% vs 19.3%; adjusted rate ratio [RR], 0.85; 95% confidence interval [CI], 0.78-0.92; P<0.001). AED use in those patients with asystole or PEA (unshockable rhythms) was associated with lower survival (10.4% vs 15.4%; adjusted RR, 0.74; 95% CI, 0.65-0.83; P<0.001). Where shockable rhythms, such as ventricular tachycardia or ventricular fibrillation, were present, AED use did not increase survival (38.4% vs 39.8%; adjusted RR, 1.00; 95% CI, 0.88-1.13; P=0.99). These trends were consistent for AED use in both monitored and nonmonitored hospital units (p>.10). For cardiac arrest due to asystole or PEA the use (or not) of an AED did not influence the rates of ROSC. For cardiac arrests due to ventricular fibrillation or pulseless ventricular tachycardia the rates of ROSC and survival at 24 h did not differ by AED use. AED use did not shorten the time to defibrillation and for those patients with ROSC, and was not associated with shorter CPR times or fewer administered defibrillations. Overall the authors concluded that the use of AEDs in hospitalised patients following cardiac arrest was not associated with improved survival.</AbstractText>Copyright © 2011 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
14,957 | Vaccine development against Trypanosoma cruzi and Chagas disease. | The pathology of Chagas disease presents a complicated and diverse picture in humans. The major complications and destructive evolutionary outcomes of chronic infection by Trypanosoma cruzi in humans include ventricular fibrillation, thromboembolism and congestive heart failure. Studies in animal models and human patients have revealed the pathogenic mechanisms during disease progression, pathology of disease and features of protective immunity. Accordingly, several antigens, antigen-delivery vehicles and adjuvants have been tested to elicit immune protection to T. cruzi in experimental animals. This review summarizes the research efforts in vaccine development against Chagas disease during the past decade. |
14,958 | The influence of atrial and ventricular pacing on the incidence of atrial fibrillation: a meta-analysis. | The effect of atrial pacing on the incidence of atrial fibrillation (AF) is unknown. Furthermore, the threshold of ventricular pacing that is associated with a higher incidence of AF has yet to be determined. Thus, we set out to determine the optimal pacing modality in patients with sinus node dysfunction (SND) for the prevention of AF.</AbstractText>Individual patient data from four contemporary pacemaker studies were gathered and analyzed. Since AF would inherently lead to a reduction in atrial pacing, percent atrial and ventricular pacing (%AP and %VP) were determined at the first follow-up visit and then used as a surrogate for all endpoints. Patients with >5 minutes of AF at the first visit were excluded. The primary endpoint was defined as 7 consecutive days of AF.</AbstractText>A total of 1,507 patients were included. During a mean follow-up of 14.3 ± 8.7 months, 77 patients developed AF (annual rate of 4.3%). The incidence of AF in the first (0-32%), second (32-66%), third (66-89%), and fourth (89-100%) quartiles of %AP was 1.3%, 5.3%, 5.8%, and 8.0%, respectively (P < 0.001). A multivariable analysis found that pacing above the first quartile was associated with a relative risk of 2.93 (95% confidence interval 1.16-7.39, P = 0.023). The grouping of %VP into first (0-2%), second (2-7%), third (7-84%), and fourth (84-100%) quartiles yielded an AF incidence of 2.4%, 3.4%, 6.6%, and 8.0%, respectively (P = 0.001).</AbstractText>We demonstrated that in patients with SND both atrial and ventricular pacing are associated with a higher incidence of AF. </AbstractText>©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.</CopyrightInformation> |
14,959 | Aldosterone promotes atrial fibrillation. | Hyperaldosteronism is associated with an increased prevalence of atrial fibrillation (AF). However, it is unclear whether this is the consequence of altered haemodynamics or a direct aldosterone effect. It was the aim of the study to demonstrate load-independent effects of aldosterone on atrial structure and electrophysiology.</AbstractText>Osmotic mini-pumps delivering 1.5 µg/h aldosterone were implanted subcutaneously in rats (Aldo). Rats without aldosterone treatment served as controls. After 8 weeks, surface electrocardiogram, the inducibility of AF, and atrial pressures were recorded in vivo. In isolated working hearts, left ventricular function was measured, and conduction in the right atrium (RA) and the left atrium (LA) was mapped epicardially. The atrial effective refractory period (AERP) was determined. Atrial tissue was analysed histologically.</AbstractText>Neither systolic nor diastolic ventricular function nor atrial pressures were altered in Aldo rats. All Aldo (11/11) showed inducible atrial arrhythmias vs. two of nine controls (P = 0.03). In Aldo, the P-wave duration and the total RA activation time were longer. Prolongation of local conduction times occurred more often in Aldo, whereas the AERP did not differ between both groups. In Aldo, atrial fibroblasts and interstitial collagen were increased, active matrix metalloproteinase 13 was reduced, and atrial myocytes were hypertrophied. The connexin 43 content was unaltered.</AbstractText>Aldosterone causes a substrate for atrial arrhythmias characterized by atrial fibrosis, myocyte hypertrophy, and conduction disturbances. The described model imputes atrial proarrhythmia directly to aldosterone, since ventricular haemodynamics appeared unaltered in this model. This mechanism may have therapeutical impact for primary and secondary prevention of AF.</AbstractText> |
14,960 | Prevalence and characteristics of early repolarization in the CASPER registry: cardiac arrest survivors with preserved ejection fraction registry. | We evaluated the prevalence and characteristics of early repolarization in patients in CASPER (Cardiac Arrest Survivors With Preserved Ejection Fraction Registry).</AbstractText>Early repolarization has been implicated in a syndrome of polymorphic ventricular tachycardia and fibrillation in patients without organic heart disease.</AbstractText>One hundred patients with apparently unexplained cardiac arrest and preserved ejection fraction underwent extensive clinical and genetic testing to unmask subclinical electrical or structural disease. A blinded independent analysis of the 12-lead electrocardiogram (ECG) was performed. Early repolarization was defined as ≥0.1 mV QRS-ST junction (J-point) elevation with terminal QRS slurring or notching in at least 2 contiguous inferior and/or lateral leads.</AbstractText>One hundred cardiac arrest patients were enrolled (40 females, age 43 ± 14 years). Forty-four were diagnosed with an established cause for cardiac arrest. Significant early repolarization was found in 19 patients, including 6 with a primary diagnosis that explained their cardiac arrest (14%), compared with 23% of the 56 patients with idiopathic ventricular fibrillation (IVF) (p = 0.23). J-point elevation in IVF patients had higher amplitude (0.25 ± 0.11 mV vs. 0.13 ± 0.05 mV, p = 0.02) and wider distribution (4.3 ± 1.3 leads vs. 2.8 ± 0.8 leads; p = 0.01) than those with an established cause of cardiac arrest. J-wave amplitude was fluctuant on serial ECGs; at least 1 ECG failed to demonstrate early repolarization in 58% of patients.</AbstractText>Early repolarization is present in a significant proportion of causally diagnosed and idiopathic VF. It is often intermittent and more pronounced in IVF patients. (Registry of Unexplained Cardiac Arrest; NCT00292032).</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,961 | Cardiac function in relation to rhythm outcome after intraoperative epicardial left atrial cryoablation. | To assess the effects of intraoperative left atrial epicardial cryoablation on rhythm and atrial and ventricular function.</AbstractText>Thirty five patients with coronary artery disease and documented atrial fibrillation underwent coronary artery bypass surgery and concomitant cryoablation. An age and gender matched control group of 35 patients with atrial fibrillation underwent bypass surgery alone. Echocardiography was performed 9 ? 32 days before and 22 ? 6 months after surgery.</AbstractText>The proportion of patients in sinus rhythm at follow-up was 63% and 34% (p = 0.04) in the cryoablation and control groups, respectively. In patients with sinus rhythm both before surgery and at follow-up, the left atrial area increased (p = 0.002) and the mitral annular excursion during atrial contraction decreased (p = 0.01) after cryoablation. The mitral flow velocity during atrial systole decreased after cryoablation (p = 0.002). The LV diameter increased (p = 0.03) and the left ventricular ejection fraction (LVEF) decreased (p = 0.03) in cryoablated but not in control patients. Continued deterioration was seen in patients with atrial fibrillation both pre- and postoperatively.</AbstractText>At long-term follow-up, a significantly higher proportion of patients was in sinus rhythm in the cryoablation than in the control group. The atrial and ventricular function had decreased at follow-up two years after surgery. This decrease was small and occurred within or close to the reference values in patients with sinus rhythm at follow-up, while patients remaining in atrial fibrillation showed a significant continued deterioration. Some subgroups were small, and the findings, although statistically significant, should be interpreted with caution.</AbstractText> |
14,962 | Echocardiographic parameters are independently associated with increased cardiovascular events in patients with chronic kidney disease. | Patients with chronic kidney disease (CKD) are associated with increased cardiovascular (CV) morbidity and mortality. Echocardiographic measures of heart structure and function have been reported to predict adverse CV outcomes in various pathologic conditions. The aim of this study is to assess whether echocardiographic parameters are independently associated with increased CV events in patients with CKD Stages 3-5.</AbstractText>We consecutively enrolled 505 CKD patients from our outpatient department of internal medicine. CV events were defined as CV death, hospitalization for unstable angina, non-fatal myocardial infarction, sustained ventricular arrhythmia, hospitalization for congestive heart failure, transient ischemia attack and stroke. The relative CV events' risk was analyzed by Cox regression methods.</AbstractText>In the multivariate analysis, old age, the presence of diabetes, coronary artery disease and atrial fibrillation; decreased serum albumin and hematocrit levels; left atrial diameter (LAD) >4.7 cm [hazard ratio (HR), 2.141; 95% confidence interval (CI), 1.155-3.971, P = 0.016]; increased left ventricular mass index (LVMI) (HR, 1.006; 95% CI, 1.002 to 1.010, P = 0.003) and left ventricular ejection fraction (LVEF) <55% (HR, 2.007; 95% CI, 1.007-3.743, P = 0.028) were independently associated with increased CV events.</AbstractText>Our findings show that LAD >4.7 cm, increased LVMI and LVEF <55% are independently associated with adverse CV outcomes in CKD patients. Screening CKD patients by means of echocardiography may help identify a high-risk group of poor CV prognosis.</AbstractText> |
14,963 | Sudden cardiac death thirty years ago and at present. The role of autonomic disturbances in acute myocardial infarction revisited. | The most common cause of sudden cardiac death is ventricular fibrillation (VF). In addition to the status, size and location of the ventricular focus, a major pathogenic mechanism triggering VF is autonomic dysbalance (disturbance). This term refers to a wide range of reflex changes in the ratio of sympathetic to vagal ventricular activation over time, occurring immediately after coronary artery occlusion at the onset of acute myocardial infarction (AMI). Another trigger of VF is autonomic disturbance due to emotional stress. Experimental and clinical research into autonomic disturbances associated with coronary artery occlusion and emotional stress was given considerable attention as early as some 30 years ago when researchers were already searching for ways of inhibiting autonomic disturbances using predominant sympathetic and vagal activation by beta-blockers (BB) and atropine, respectively. The aim of our paper is to compare results obtained 30 years ago with current status of experimental and clinical research into SCD prevention. Another aim is to identify questions that have remained unanswered to date; answers to these outstanding questions could help further reduce the risk of SCD. |
14,964 | Is antiarrhythmic treatment in the elderly different? a review of the specific changes. | Aging is associated with electrical and structural changes of the myocardium. The response to catecholamines is also reduced and the baroreceptor reflex activity is blunted. These aspects conceivably affect the response to antiarrhythmic drugs in the elderly. Furthermore, physiological parameters change in older age, affecting the pharmacokinetics of drugs. In this article, the literature on the pharmacokinetics and pharmacodynamics of antiarrhythmic drugs in elderly subjects is reviewed with the purpose of improving their optimal and safe prescription. Pharmacokinetic studies of antiarrhythmic drugs in the elderly are sparse, and there are no data available for procainamide and propafenone. Mean dose reductions calculated for elderly patients relative to younger patients are 60% for digoxin, 19% for diltiazem, 32% for disopyramide, 31% for flecainide, 40% for metoprolol, 35% for quinidine, 29% for sotalol and 26% for verapamil. No dose reductions are required for dofetilide or dronedarone. The clearance of dofetilide is not affected by age after correction for renal function. The dosage of dofetilide is individualized according to an algorithm based on the corrected QT (QTc) interval and renal function. Although the area under the plasma concentration-time curve (AUC) for dronedarone is larger in elderly patients, the dose should not be reduced because the registered dose has specifically been studied in an elderly population. In elderly patients with renal insufficiency, hepatic impairment, heart failure or certain genetic variants, the pharmacokinetics of antiarrhythmic drugs might be affected to an even greater extent, meaning additional dosage adjustments are necessary. With increasing age, the number of prescribed drugs increases because of co-morbidity, making interactions between drugs more likely. Several drugs interact with antiarrhythmic drugs, leading to clinically relevant changes in drug concentrations or AUC values. Furthermore, several drugs with non-cardiovascular indications appear to have QTc prolonging effects. The combination of these drugs with antiarrhythmic drugs that affect the QTc interval increases the risk of developing torsades de pointes and should therefore be avoided. Altered effects of drugs in the elderly can also be the result of age-related changes in the cardiovascular system. For example, atenolol and sotalol show greater effects, i.e. reductions in heart rate and increased probability of adverse effects, at a given plasma concentration in older subjects compared with younger subjects. It remains unclear whether old age as such is a determinant for reduced or modified efficacy of antiarrhythmic drugs. In a randomized study it was found that patients aged ≥65 years with atrial fibrillation had better survival with rate control than with rhythm control. However, different treatment strategies were compared and the results cannot be extrapolated to indicate better survival with a specific antiarrhythmic drug. Antiarrhythmic drugs will remain the first-line approach in most patients for the prevention or suppression of atrial and ventricular arrhythmias. As a rule of thumb, a 50% reduction in the starting dose of antiarrhythmic drugs compared with younger patients appears a wise approach in elderly patients. However, this does not apply to dofetilide and dronedarone. The selection of antiarrhythmic drugs in the elderly is predominantly determined by factors such as the treatment target, assumed patient compliance, possible drug interactions, co-morbidity, and renal and liver function. Efficacy and safety monitoring should take into account symptoms, ECG findings, rhythm recordings, plasma drug concentrations and other laboratory parameters. |
14,965 | Regulatory pathways for development of antiarrhythmic drugs for management of atrial fibrillation/flutter. | New antiarrhythmic drugs are urgently required for the treatment of atrial fibrillation (AF), an increasingly common sustained cardiac arrhythmia seen predominantly in the elderly population. Pharmaceutical companies are generally interested in this important group of patients and a relatively large number of antiarrhythmic agents are under development for several indications relating to AF, predominantly rhythm and rate management. Because of the significant clinical consequences of the arrhythmia, it has been recognized that controlled trials in patients with AF should assess the effect of therapy in several major outcome domains such as mortality, morbidity, and hospitalization, with an emphasis on stroke and heart failure. As part of a regular series of meetings, the European Society of Cardiology recently met with European regulators and representatives of the pharmaceutical industry to review the current status of medical therapies for AF. Special attention has been paid to the debate on the relevant clinical endpoints in future AF trials and their implications for drug indications. The need for large-scale major cardiovascular outcome and comparator studies for the approval of drugs designed to manage rhythm and/or control the rate has been discussed. The requirements for appropriate ancillary studies, including quality of life and left ventricular function assessment and cost-effectiveness analysis, have been identified. This article reports the discussions that were held. |
14,966 | Ultrafast and whole-body cooling with total liquid ventilation induces favorable neurological and cardiac outcomes after cardiac arrest in rabbits. | In animal models of cardiac arrest, the benefit afforded by hypothermia is closely linked to the rapidity of the decrease in body temperature after resuscitation. Because total liquid ventilation (TLV) with temperature-controlled perfluorocarbons induces a very rapid and generalized cooling, we aimed to determine whether this could limit the post-cardiac arrest syndrome in a rabbit model. We especially focused on neurological, cardiac, pulmonary, liver and kidney dysfunctions.</AbstractText>Anesthetized rabbits were submitted to either 5 or 10 minutes of untreated ventricular fibrillation. After cardiopulmonary resuscitation and resumption of a spontaneous circulation, the animals underwent either normothermic life support (control) or therapeutic hypothermia induced by TLV. The latter procedure decreased esophageal and tympanic temperatures to 32°C to 33°C within only 10 minutes. After rewarming, the animals submitted to TLV exhibited an attenuated neurological dysfunction and decreased mortality 7 days later compared with control. The neuroprotective effect of TLV was confirmed by a significant reduction in brain histological damages. We also observed limitation of myocardial necrosis, along with a decrease in troponin I release and a reduced myocardial caspase 3 activity, with TLV. The beneficial effects of TLV were directly related to the rapidity of hypothermia induction because neither conventional cooling (cold saline infusion plus external cooling) nor normothermic TLV elicited a similar protection.</AbstractText>Ultrafast cooling instituted by TLV exerts potent neurological and cardiac protection in an experimental model of cardiac arrest in rabbits. This could be a relevant approach to provide a global and protective hypothermia against the post-cardiac arrest syndrome.</AbstractText> |
14,967 | Atrial fibrillation in elderly patients with heart failure: convergence of two cardiovascular epidemics in the 21st Century. | Atrial fibrillation and heart failure have been called the twin cardiovascular epidemics of the 21st Century. The prevalence of both conditions is increasing in the elderly and often the two conditions coexist in the same patients, leading to worse outcomes. Current data show that rate control and rhythm control are both reasonable strategies for the treatment of atrial fibrillation in heart failure patients. Emerging data suggest the beneficial effects of novel therapeutic approaches such as cardiac resynchronization therapy, and pulmonary vein isolation on left ventricular remodeling and functional outcomes. Anticoagulation remains a mainstay of therapy for stroke prevention in this high-risk population. |
14,968 | Lifestyle and atrial fibrillation. | Lifestyle factors, in particular dietary intake, have been recognized as important, modifiable risk factors for cardiovascular disease. Consuming a heart-healthy diet lowers the individual's risk for cardiovascular disease. Data on the relationship between lifestyle and atrial fibrillation are controversial; however, the strong association between obesity, atrial/ventricular dysfunction and a nonhealthy lifestyle and atrial fibrillation, suggests that a correction of nutritional habits could prevent the development of arrhythmias through a reduction of underlying cardiac diseases. Today, the Mediterranean diet is considered one of the most effective in terms of its prevention of cardiovascular disease. |
14,969 | Combination of B-type natriuretic peptide and minute ventilation/carbon dioxide production slope improves risk stratification in patients with diastolic heart failure. | Recent studies demonstrated that the minute ventilation/carbon dioxide production (VE/VCO(2)) slope more powerfully predicted mortality, hospitalization, or both than peak oxygen consumption (VO(2)) in systolic heart failure. However, the prognostic values of these two parameters in diastolic heart failure remained unclear.</AbstractText>The patients with diastolic heart failure were recruited from April 2006 to May 2007, and underwent cardiopulmonary exercise testing. Plasma BNP concentration was measured using Triage BNP immunoassay method.</AbstractText>Of the 224 patients enrolled, mean values for age and New York Heart Association (NYHA) class were 68.8 ± 9.0 years and 2.38 ± 0.53, respectively. During the mean follow-up of 30 months, 57 patients died (36 from cardiovascular death). Univariate Cox regression analysis showed that age, NYHA class, atrial fibrillation, diabetes mellitus, left ventricular diastolic dysfunction, peak VO(2), VE/VCO(2) slope, and plasma BNP were significantly associated with mortality. Multivariate analysis revealed that plasma BNP, VE/VCO(2) slope, and age remained independent predictors for cardiovascular and all-cause mortalities, with the strongest prognostic power of plasma BNP (χ(2) ≥ 31.4, P < 0.001). In addition to plasma BNP and clinical predictors, the VE/VCO(2) slope could provide independent and incremental prognostic value of cardiovascular (χ(2) = 60.6 vs 51.7; P = 0.009) and all-cause mortalities (χ(2) = 62.8 vs 54.2; P = 0.015) with increased χ(2) value of Cox regression model.</AbstractText>In diastolic heart failure, plasma BNP is the strongest predictor of mortality, and VE/VCO(2) slope provides independent and additive prognostic information, which suggests that combination of plasma BNP and VE/VCO(2) slope can improve risk stratification.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,970 | Sustained ventricular fibrillation in an alert patient: preserved hemodynamics with a left ventricular assist device. | Emergency medical services (EMS) encountered an alert patient with sustained ventricular fibrillation with preserved hemodynamics via a left ventricular assist device (LVAD). Multiple firings of the patient's implantable defibrillator were the only sign that this patient was experiencing the usually fatal ventricular arrhythmia. Initial attempts at rhythm conversion with amiodarone and 200-J biphasic shocks were unsuccessful. The patient was finally defibrillated to normal sinus rhythm after a 360-J biphasic shock. This case conference highlights the increasing prevalence of LVADs. These devices are used not only as a bridge to cardiac transplantation, but also as definitive therapy for patients in end-stage cardiac failure. Ventricular fibrillation has been shown to be well tolerated in patients with LVADs, and we discuss a standard of care for these patients. The occurrence of sustained ventricular fibrillation in patients with ventricular assist devices represents a challenging situation for EMS and emergency department providers and one that will be increasingly encountered in the future. |
14,971 | Supplemental studies for cardiovascular risk assessment in safety pharmacology: a critical overview. | Safety Pharmacology studies for the cardiovascular risk assessment, as described in the ICH S7A and S7B guidelines, appear as being far from sufficient. The fact that almost all medicines withdrawn from the market because of life-threatening tachyarrhythmias (torsades-de-pointes) were shown as hERG blockers and QT interval delayers led the authorities to focus mainly on these markers. However, other surrogate biomarkers, e.g., TRIaD (triangulation, reverse-use-dependence, instability and dispersion of ventricular repolarization), have been identified to more accurately estimate the drug-related torsadogenic risk. In addition, more attention should be paid to other arrhythmias, not related to long QT and nevertheless severe and/or not self-extinguishing, e.g., atrial or ventricular fibrillation, resulting from altered electrical conduction or heterogeneous shortening of cardiac repolarization. Moreover, despite numerous clinical cases of drug-induced pulmonary hypertension, orthostatic hypotension, or heart valvular failure, few safety investigations are still conducted on drug interaction with cardiac and regional hemodynamics other than changes in aortic blood pressure evaluated in conscious large animals during the core battery mandatory studies. This critical review aims at discussing the usefulness, relevance, advantages, and limitations of some preclinical in vivo, in vitro, and in silico models, with high predictive values and currently used in supplemental safety studies. |
14,972 | Facilitation of hypothermia by quinpirole and 8-OH-DPAT in a rat model of cardiac arrest. | Therapeutic hypothermia improves outcome after cardiac arrest. Dopamine D(2) agonists and serotonin 5-HT(1A) agonists lower body temperature by decreasing the set-point. We investigated the effect of these drugs on temperature and cerebral recovery of rats after cardiac arrest.</AbstractText>Male Wistar-Han rats were subjected to 6 min of cardiac arrest due to ventricular fibrillation. Following restoration of circulation, 1mg quinpirole, 1mg 8-OH-DPAT or vehicle were injected subcutaneously. Body temperature was monitored for 48 h. One additional group was kept normothermic. Animals were neurologically tested by a tape removal test. After 7 days, histology of hippocampal CA-1 sector was analysed with Nissl and TUNEL staining.</AbstractText>Rats became spontaneously hypothermic after cardiac arrest. Induction of hypothermia was facilitated by both quinpirole (-0.033 ± 0.008°C/min) and 8-OH-DPAT (-0.029 ± 0.010°C/min) when compared to vehicle (-0.020 ± 0.005°C/min). Total 'dose' of hypothermia (area under the curve) was not different. All animals showed a neurological deficit, which improved with time; after 7 days, test results of the normothermic group (30 [11-88]s) still tended to be worse than those of the hypothermic groups (vehicle 8 [6-14]s, quinpirole 9 [4-17]s, 8-OH-DPAT 10 [8-22]s). There were no clear differences in Nissl or TUNEL histology after 7 days.</AbstractText>Both quinpirole and 8-OH-DPAT led to faster induction of hypothermia. However, the outcome was not different from spontaneous hypothermia, probably because the total 'dose' of hypothermia was not influenced.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,973 | Utility of a novel watch-based pulse detection system to detect pulselessness in human subjects. | The Wriskwatch is a novel, watch-based pulse detection device that detects the loss of a radial pulse via advanced pulse detection technology and immediately contacts emergency medical systems.</AbstractText>The purpose of this first-in-man, prospective, single-blinded, phase 1 study was to evaluate the ability of this device to detect motionlessness and pulselessness in human subjects as a simulation of sudden cardiac death.</AbstractText>The study cohort consisted of 34 patients: 24 hospitalized patients and 10 presenting for implantable cardioverter-defibrillator (ICD) testing. We simulated loss of pulse in our hospitalized patients via blood pressure cuff inflation to occlude the brachial arterial pulse at random times in 20 subjects with no inflations in 4 while the patients were instructed to keep perfectly still. Of the 10 patients undergoing ventricular fibrillation (VF) induction during ICD testing, the exact times of VF induction were recorded. A blinded reviewer determined if and when motion and pulse were lost in all patients using only data from the device.</AbstractText>Of the 34 patients, 2 had an unusable signal, 1 had device ejection during ICD testing, and 2 had too much motion artifact and were excluded (5/34 patients, or 14.7% of the total cohort). Of the 29 remaining subjects, 4 had no loss of pulse of which the device correctly identified 3. In the remaining 25 patients, the device correctly identified the time of pulselessness in 23 of 25 (16/17 hospitalized patients and 7/8 ICD patients). Overall, the Wriskwatch was worn for a total of 561.2 minutes. Pulselessness was present for 5.8 minutes. The sensitivity of the watch to detect pulse status (based on 15-second intervals) was 99.9%, and the specificity was 90.3%.</AbstractText>The Wriskwatch is a novel device that shows promise as a tool to hasten activation of emergency medical systems and facilitate early defibrillation in patients with cardiac arrest.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,974 | Robotic catheter ablation of left ventricular tachycardia: initial experience. | Catheter ablation of ventricular tachycardia (VT) can be technically challenging due to difficulty with catheter positioning in the left ventricle (LV) and achieving stable contact. The Hansen Sensei Robotic system (HRS) has been used in atrial fibrillation but its utility in VT is unclear.</AbstractText>The purpose of this study was to test the technical feasibility of robotic catheter ablation of LV ventricular tachycardia (VT) using the HRS.</AbstractText>Twenty-three patients underwent LV VT mapping and ablation with the HRS via a transseptal, transmitral valve approach. Nineteen patients underwent substrate mapping and ablation (18 had ischemic cardiomyopathy, 1 had an apical variant of hypertrophic cardiomyopathy). Four patients had focal VT requiring LV VT mapping and ablation. Procedural endpoints included substrate modification by endocardial scar border ablation and elimination of late potentials, or elimination of inducible focal VT.</AbstractText>Mapping and ablation were entirely robotic without requiring manual catheter manipulation in all patients and reaching all LV regions with stable contact. Fluoroscopy time of the LV procedure was 22.2 ± 11.2 minutes. Radiofrequency time was 33 ± 21 minutes. Total procedural times were 231 ± 76 minutes. Complications included a left groin hematoma (opposite to the HRS sheath), 1 pericardial effusion without tamponade that was drained successfully, and transient right ventricular failure in a patient with previous left ventricular assist device. At 13.4 ± 6.7 months of follow-up (range 1-19 months), recurrence of VT occurred in 3 of 23 patients.</AbstractText>Our initial experience suggests that the HRS allows successful mapping and ablation of LV VT.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,975 | Intracardiac QT integral on far-field ICD electrogram predicts sustained ventricular tachyarrhythmias in ICD patients. | Prediction of sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) could help to guide preventive interventions in at-risk patients. The QRST integral (∫QT) reflects intrinsic repolarization properties.</AbstractText>The objective of this study was to determine whether intracardiac ∫QT predicts VT/VF in the next few months in patients with implantable cardioverter defibrillators (ICDs).</AbstractText>Far-field (FF) and near-field (NF) right ventricular intracardiac electrograms (EGMs) were recorded via telemetry in 46 patients with structural heart disease and ICDs implanted for secondary prevention of sudden cardiac death. Epochs of 4.9 ± 0.4 minutes during sinus rhythm (mean heart rate 70.9 ± 15.2 beats/min) and ventricular pacing at 105 beats/min were analyzed. Mean ∫QT was calculated on FF and NF EGMs as the algebraic sum of areas under the QRST curve and adjusted by mean heart rate. Patients were followed up for at least 3 months. True VT/VF events treated by the ICD served as the end point.</AbstractText>During a mean follow-up of 4.6 months, 22 patients (48%) were treated for VT/VF. Unadjusted and adjusted by heart rate, FF EGM ∫QT in sinus rhythm was a significant predictor of VT/VF (unadjusted ∫QT hazard ratio 1.007; 95% confidence interval 1.002 to 1.0013; P = .007; adjusted ∫QT hazard ratio 1.68; 95% confidence interval 1.19 to 2.36; P = .002). The highest quartile of intracardiac ∫QT predicted VT/VF (log-rank test P = .042) and identified patients at risk with a specificity of 86% and positive predictive value of 73%.</AbstractText>Increased intracardiac FF EGM ∫QT predicts VT/VF in patients with structural heart disease and secondary prevention ICDs.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,976 | Cardiac arrest provoked by itraconazole and amiodarone interaction: a case report. | Azoles, and specifically itraconazole, are often prescribed for the treatment of fungal diseases or empirically for persistent sepsis in patients who are neutropenic or in intensive care. Occasional cardiovascular adverse events have been associated with itraconazole use, and are usually attributed to the interaction of itraconazole with cisapride, terfenadine or digoxin. Its interaction with amiodarone has not been previously described.</AbstractText>A 65-year-old Caucasian man was admitted to the Intensive Care Unit at our facility for an extensive ischemic stroke associated with atrial fibrillation. Due to rapid ventricular response he was started on intravenous amiodarone and few days later itraconazole was also prescribed for presumed candidemia. After receiving the first dose our patient became profoundly hypotensive but responded rapidly to fluids and adrenaline. Then, two months later, itraconazole was again prescribed for confirmed fungemia. After receiving the first dose via a central venous catheter our patient became hypotensive and subsequently arrested. He was resuscitated successfully, and as no other cause was identified the arrest was attributed to septic shock and his antifungal treatment was changed to caspofungin. When sensitivity test results became available, antifungal treatment was down-staged to itraconazole and immediately after drug administration our patient suffered another arrest and was once again resuscitated successfully. This time the arrest was related to itraconazole, which was discontinued, and from then on our patient remained stable until his discharge to our neurology ward.</AbstractText>Itraconazole and amiodarone coadministration can lead to serious cardiovascular adverse events in patients who are critically ill. Intensivists, pharmacists and medical physicians should be aware of the interaction of these two commonly used drugs.</AbstractText> |
14,977 | Radiated radiofrequency immunity testing of automated external defibrillators--modifications of applicable standards are needed. | We studied the worst-case radiated radiofrequency (RF) susceptibility of automated external defibrillators (AEDs) based on the electromagnetic compatibility (EMC) requirements of a current standard for cardiac defibrillators, IEC 60601-2-4. Square wave modulation was used to mimic cardiac physiological frequencies of 1-3 Hz. Deviations from the IEC standard were a lower frequency limit of 30 MHz to explore frequencies where the patient-connected leads could resonate. Also testing up to 20 V/m was performed. We tested AEDs with ventricular fibrillation (V-Fib) and normal sinus rhythm signals on the patient leads to enable testing for false negatives (inappropriate "no shock advised" by the AED).</AbstractText>We performed radiated exposures in a 10 meter anechoic chamber using two broadband antennas to generate E fields in the 30-2500 MHz frequency range at 1% frequency steps. An AED patient simulator was housed in a shielded box and delivered normal and fibrillation waveforms to the AED's patient leads. We developed a technique to screen ECG waveforms stored in each AED for electromagnetic interference at all frequencies without waiting for the long cycle times between analyses (normally 20 to over 200 s).</AbstractText>Five of the seven AEDs tested were susceptible to RF interference, primarily at frequencies below 80 MHz. Some induced errors could cause AEDs to malfunction and effectively inhibit operator prompts to deliver a shock to a patient experiencing lethal fibrillation. Failures occurred in some AEDs exposed to E fields between 3 V/m and 20 V/m, in the 38 - 50 MHz range. These occurred when the patient simulator was delivering a V-Fib waveform to the AED. Also, we found it is not possible to test modern battery-only-operated AEDs for EMI using a patient simulator if the IEC 60601-2-4 defibrillator standard's simulated patient load is used.</AbstractText>AEDs experienced potentially life-threatening false-negative failures from radiated RF, primarily below the lower frequency limit of present AED standards. Field strengths causing failures were at levels as low as 3 V/m at frequencies below 80 MHz where resonance of the patient leads and the AED input circuitry occurred. This plus problems with the standard's' prescribed patient load make changes to the standard necessary.</AbstractText> |
14,978 | E/e' ratio is a strong prognostic predictor of mortality in patients with non-valvular atrial fibrillation with preserved left ventricular systolic function. | The purpose of this study was to investigate the prognostic values of the E/e' ratio and other echocardiographic and clinical parameters in patients with non-valvular atrial fibrillation (AF) with preserved left ventricular (LV) systolic function.</AbstractText>A total of 488 patients (322 men, age: 66 ± 11 years) with non-valvular AF with preserved LV systolic function (LV ejection fraction >50%) were included. The E and e' velocities were measured in 5 consecutive heart beats and averaged. Mean follow-up duration after enrollment was 17.7 ± 5.3 months. All-cause deaths occurred in 45 patients (cardiovascular deaths: n=29). There were significant differences in age (65.6 ± 11.3 vs. 71.5 ± 9.1, P < 0.001) and hemoglobin concentration (13.6 ± 2.9 vs. 11.5 ± 3.4g/dl, P<0.0001) between the deceased group and the survivors. E/e' ratio in the deceased group was significantly higher than that in the survivors (17.67 ± 3.39 vs. 10.8 ± 3.30, P < 0.001). Survival analysis showed that a high E/e' ratio (> 15.0) represents a poorer prognosis (P < 0.001 by Log-Rank test) than an E/e' ratio of 15 and below. Multivariate analysis identified 2 significant variables that were predictive of all-cause deaths: hemoglobin (hazard ratio (HR)=0.806, 95% confidence interval (CI) = 0.733-0.886, P < 0.0001), and E/e' > 15 (HR=3.064, 95%CI = 1.38-6.804, P = 0.006).</AbstractText>E/e' ratio is a useful independent prognostic parameter for predicting mortality in patients with AF with preserved LV systolic function.</AbstractText> |
14,979 | Connexin 43 gene therapy prevents persistent atrial fibrillation in a porcine model. | Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and effective treatment of AF still remains an unmet medical need. AF is associated with atrial conduction disturbances caused by electrical and/or structural remodelling. We hypothesized that AF suppresses expression of the gap junction protein connexin (Cx) 43 and that Cx43 gene transfer to both atria would prevent persistent AF. The first aim of this study was to assess whether AF is associated with connexin remodelling in a porcine model. A strategy to suppress persistent AF by gene therapy was then developed and evaluated in vivo.</AbstractText>AF was induced in domestic pigs via atrial burst pacing, causing a 62.4% reduction in atrial Cx43 protein. Adenoviruses encoding for Cx43 (AdCx43) or green fluorescent protein (AdGFP) were injected into both atria, followed by epicardial electroporation to enhance transgene expression. Combining direct injection of adenoviruses with electroporation achieved GFP reporter gene expression in ∼50% of atrial cells in vivo. AdCx43-treated animals exhibited a 2.5-fold increase in atrial Cx43 protein content and did not develop persistent AF during the observation period of 14 days. In contrast, control animals developed persistent AF within 7.4 ± 0.5 days. Rapid ventricular heart rates during AF led to deterioration of cardiac function in control pigs but not in pigs treated with AdCx43.</AbstractText>Our results highlight the contribution of Cx43 to the pathophysiology of AF and demonstrate the viability of gene therapy for prevention of atrial arrhythmias.</AbstractText> |
14,980 | Radiofrequency ablation of atrial fibrillation in patients with mechanical mitral valve prostheses safety, feasibility, electrophysiologic findings, and outcomes. | The purpose of this study was to evaluate the feasibility, safety, and outcomes of radiofrequency ablation of atrial fibrillation (AF) in patients with mechanical mitral valve replacement (MVR).</AbstractText>The role of ablative therapy in patients with MVR is not yet established, with safety concerns and very few outcome data.</AbstractText>Between January 2003 and December 2008, we followed up 81 patients with MVR undergoing first-time AF ablation (compared with 162 age- and sex-matched controls). Arrhythmia recurrences were identified by symptoms with documentation, event monitoring, Holter monitoring, and electrocardiograms.</AbstractText>All MVR and control patients underwent ablation under therapeutic international normalized ratio. No entrapment of catheters or stroke occurred. There were no differences in terms of procedure-related complications between the groups (p = NS). Patients with MVR had larger atria (p < 0.0001), lower left ventricular ejection fractions (p = 0.0001), and more concomitant atrial flutter at baseline (p < 0.0001). Over a 24-month follow-up, they had higher recurrence rates compared with controls (49.4% vs. 27.7% after a single ablation, p = 0.0006). The creation of flutter lines significantly reduced recurrences in patients with any history of atrial flutter (16.7% vs. 60.9%, p = 0.009). At last follow-up, 82.7% of MVR patients had their arrhythmia controlled (69.1% not receiving antiarrhythmic drugs).</AbstractText>Radiofrequency ablation is feasible and safe for patients with MVR. It allowed restoration of sinus rhythm in a substantial proportion of patients undergoing ablation. An abnormal atrial substrate underlies recurrences in these patients. The ablation procedure needs to be further refined with a focus on extra pulmonary vein triggers and concomitant flutters to improve outcomes.</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,981 | True bipolar and integrated bipolar sensing and detection by implantable defibrillators. | Sensing and detection can be performed in true bipolar or integrated bipolar configuration by implantable defibrillators. New Medtronic generators (Medtronic Inc., Minneapolis, MN, USA) can be configured so that the sensing function of the device can be either true bipolar or integrated bipolar. We compared the sinus rhythm R-wave amplitude and detection time of induced ventricular fibrillation (VF) at implant (acute phase), and sinus rhythm R-wave amplitude 3 months or more after the implant (chronic phase) in these two configurations.</AbstractText>Twenty-eight patients were studied in the acute phase, and a subgroup of 15 patients was tested in the chronic phase. The generators were Medtronic model numbers D224VRC, D224TRK, D224DRG, D284VRC, D284TRK, and D284DRG. The leads were Medtronic 6947 or 6935. Sensing was evaluated by recording the electrogram and measuring the R-wave peak-to-peak amplitude in the two configurations. Detection was evaluated by measuring the detection time in the two configurations in two consecutive inductions. The detection time was measured on programmer paper from the marker of the T shock to the marker of VF.</AbstractText>The acute-phase values were: R wave in true bipolar configuration 13.9 ± 7.1 mV, R wave in integrated bipolar configuration 13.6 ± 6.9 mV (p = 0.38),VF detection time in true bipolar configuration 3.12 ± 0.39 seconds, and VF detection time in integrated bipolar configuration 3.17 ± 0.39 seconds (p = 0.52).</AbstractText>Sensing and detection at implant were not significantly different between the true bipolar and the integrated bipolar configurations for the tested leads and generators.</AbstractText> |
14,982 | Out-of-hospital cardiac arrest surveillance --- Cardiac Arrest Registry to Enhance Survival (CARES), United States, October 1, 2005--December 31, 2010. | <AbstractText Label="PROBLEM/CONDITION" NlmCategory="OBJECTIVE">Each year, approximately 300,000 persons in the United States experience an out-of-hospital cardiac arrest (OHCA); approximately 92% of persons who experience an OHCA event die. An OHCA is defined as cessation of cardiac mechanical activity that occurs outside of the hospital setting and is confirmed by the absence of signs of circulation. Whereas an OHCA can occur from noncardiac causes (i.e., trauma, drowning, overdose, asphyxia, electrocution, primary respiratory arrests, and other noncardiac etiologies), the majority (70%--85%) of such events have a cardiac cause. The majority of persons who experience an OHCA event, irrespective of etiology, do not receive bystander-assisted cardiopulmonary resuscitation (CPR) or other timely interventions that are known to improve the likelihood of survival to hospital discharge (e.g., defibrillation). Because nearly half of cardiac arrest events are witnessed, efforts to increase survival rates should focus on timely and effective delivery of interventions by bystanders and emergency medical services (EMS) personnel. This is the first report to provide summary data from an OHCA surveillance registry in the United States.</AbstractText>This report summarizes surveillance data collected during October 1, 2005-- December 31, 2010.</AbstractText>In 2004, CDC established the Cardiac Arrest Registry to Enhance Survival (CARES) in collaboration with the Department of Emergency Medicine at the Emory University School of Medicine. This registry evaluates only OHCA events of presumed cardiac etiology that involve persons who received resuscitative efforts, including CPR or defibrillation. Participating sites collect data from three sources that define the continuum of emergency cardiac care: 911 dispatch centers, EMS providers, and receiving hospitals. OHCA is defined in CARES as a cardiac arrest that occurred in the prehospital setting, had a presumed cardiac etiology, and involved a person who received resuscitative efforts, including CPR or defibrillation.</AbstractText>During October 1, 2005--December 31, 2010, a total of 40,274 OHCA records were submitted to the CARES registry. After noncardiac etiology arrests and missing hospital outcomes were excluded from the analysis (n = 8,585), 31,689 OHCA events of presumed cardiac etiology (e.g., myocardial infarction or arrhythmia) that received resuscitation efforts in the prehospital setting were analyzed. The mean age at cardiac arrest was 64.0 years (standard deviation [SD]: 18.2); 61.1% of persons who experienced OHCA were male (n = 19,360). According to local EMS agency protocols, 21.6% of patients were pronounced dead after resuscitation efforts were terminated in the prehospital setting. The survival rate to hospital admission was 26.3%, and the overall survival rate to hospital discharge was 9.6%. Approximately 36.7% of OHCA events were witnessed by a bystander. Only 33.3% of all patients received bystander CPR, and only 3.7% were treated by bystanders with an automated external defibrillator (AED) before the arrival of EMS providers. The group most likely to survive an OHCA are persons who are witnessed to collapse by a bystander and found in a shockable rhythm (e.g., ventricular fibrillation or pulseless ventricular tachycardia). Among this group, survival to discharge was 30.1%. A subgroup analysis was performed among persons who experienced OHCA events that were not witnessed by EMS personnel to evaluate rates of bystander CPR for these persons. After exclusion of 3,400 OHCA events that occurred after the arrival of EMS providers, bystander CPR information was analyzed for 28,289 events. In this group, whites were significantly more likely to receive CPR than blacks, Hispanics, or members of other racial/ethnic populations (p<0.001). Overall survival to hospital discharge of patients whose events were not witnessed by EMS personnel was 8.5%. Of these, patients who received bystander CPR had a significantly higher rate of overall survival (11.2%) than those who did not (7.0%) (p<0.001).</AbstractText>CARES data have helped identify opportunities for improvement in OHCA care. The registry is being used continually to monitor prehospital performance and selected aspects of hospital care to improve quality of care and increase rates of survival following OHCA. CARES data confirm that patients who receive CPR from bystanders have a greater chance of surviving OHCA than those who do not.</AbstractText>Medical directors and public health professionals in participating communities use CARES data to measure and improve the quality of prehospital care for persons experiencing OHCA. Tracking performance longitudinally allows communities to better understand which elements of their care are working well and which elements need improvement. Education of public officials and community members about the importance of increasing rates of bystander CPR and promoting the use of early defibrillation by lay and professional rescuers is critical to increasing survival rates. Reporting at the state and local levels can enable state and local public health and EMS agencies to coordinate their efforts to target improving emergency response for OHCA events, regardless of etiology, which can lead to improvement in OHCA survival rates.</AbstractText> |
14,983 | Predicting mortality and hospital admission in patients with COPD: significance of NT pro-BNP, clinical and echocardiographic assessment. | To quantify the ability of N-terminal pro-brain natriuretic peptide (NT pro-BNP) to predict mortality and hospitalization in patients with chronic obstructive airways disease (COPD).</AbstractText>Prospective single-centre observational study of 140 consecutive patients aged at least 18 years with COPD between 27 March 2004 and 28 February 2008 (median follow-up 3.9 years).</AbstractText>Sixty-five (46%) men, 26 (19%) O2 therapy, 115 (82%) smokers, 38 (27%) patients receiving diuretics, 15 (11%) left-ventricular ejection fraction less than 45%. Median [interquartile range (IQR)] NT pro-BNP concentration 16.2 (25.4) pmol/l. NT pro-BNP was higher in those with a dilated left atrium (P<0.001), aortic stenosis (P=0.02), left-ventricular systolic dysfunction (P=0.027), right ventricular impairment (P=0.011), atrial fibrillation (P<0.001), patients receiving diuretics (P=0.010) and angiotensin-converting enzyme (ACE) inhibitors (P=0.006). One-year mortality and hospitalization rates were 2.9 and 25.4%. The median (IQR) time to hospitalization and length of first hospital stay: 383.5 (605) and 4.0 (7.0) days. NT pro-BNP was an excellent discriminator of right-ventricular impairment (C statistic=0.90) and predicted survival (highest quartile versus lowest quartile relative risk=3.02, P=0.001), but not hospital admission. After adjustment this association was not significant.</AbstractText>NT pro-BNP predicts survival, but not hospital admission in patients with COPD. The ability of NT pro-BNP to independently predict death or hospitalization is superseded by the presence of a dilated left atrium, aortic stenosis and left-ventricular systolic dysfunction.</AbstractText> |
14,984 | Marine n-3 fatty acids, atrial fibrillation and QT interval in haemodialysis patients. | Patients treated with haemodialysis are at high risk of sudden cardiac death (SCD) often caused by arrhythmias. Atrial fibrillation (AF) is frequent among haemodialysis patients and is associated with increased mortality. Prolonged QTc is a risk marker of ventricular arrhythmia and is thereby associated with SCD. Studies have suggested that n-3 PUFA may have an antiarrhythmic effect, but the exact mechanism is not clear. The aim of this study was to examine whether AF was associated with n-3 PUFA in plasma phospholipids and whether supplementation with n-3 PUFA would shorten the QTc interval in haemodialysis patients compared to placebo. In a double-blinded randomised, placebo-controlled intervention trial 206 haemodialysis patients with CVD were treated with 1·7 g n-3 PUFA or placebo (olive oil) daily for 3 months. Blood samples and electrocardiogram evaluations were carried out at baseline and after 3 months. The QT interval, PQ interval and heart rate were measured in all patients with sinus rhythm (SR). At baseline 13 % of patients had AF. The content of the n-3 PUFA, DHA, was significantly lower (P < 0·05) in serum of patients with AF compared with patients with SR. Thus, the DHA content was independently negatively associated with AF. Supplementation with n-3 PUFA did not shorten the QT interval significantly compared to the placebo group (P = 0·42), although subgroup analysis within the n-3 PUFA group revealed a shortening effects on QTc (P = 0·01). In conclusion, an inverse association was found between the presence of AF and the plasma DHA in haemodialysis patients. Intervention with n-3 PUFA did not shorten the QTc interval compared to placebo. |
14,985 | [Prevention of sudden cardiac death by the implantable cardioverter defibrilator]. | INTRODUCTION; Sudden cardiac death or, as it is also called, a modern man's killer occurs a few hours after the beginning of the disease. Sudden death is the one that happens within an hour from the onset of the subjective discomforts regardless of the existence of any previous disease. According to modern statistics, 450.000 people die suddenly in the USA and 150,000 in Germany. CAUSES OF SUDDEN DEATH: The most frequent causes of sudden death are cardiologic or, in other words, a heart rhythm disorder such as ventricular tachycardia, ventricular fibrillation and bradycardiac rhythm disorder. All these reasons can be efficiently prevented by the implantation of the cardioverter defibrillators. IMPLANTABLE CARDIOVERTER DEFIBRILLATOR: In comparison with the already known medications, the defibrillator seems to be the most efficient in prevention of sudden cardiac death. This fact has been confirmed by large multicentre studies. The implantation itself is a routine procedure. It lasts about an hour and it often passes without any complications. The patient leaves the hospital a few days after the procedure. About 150 of these procedures are performed per year at the Institute of Cardiovascular Diseases Vojvodina. The Social Insurance Fund bears medical costs and the patient only pays the participation fee, which is symbolical if compared to the value and use of the device. Owing to this fact, this device is available to every patient thus making the efficient sudden cardiac death prevention possible. |
14,986 | Risk factor and prediction modeling for sudden cardiac death in women with coronary artery disease.<Pagination><StartPage>1703</StartPage><EndPage>1709</EndPage><MedlinePgn>1703-9</MedlinePgn></Pagination><ELocationID EIdType="doi" ValidYN="Y">10.1001/archinternmed.2011.328</ELocationID><Abstract><AbstractText Label="BACKGROUND" NlmCategory="BACKGROUND">To our knowledge, the risk of sudden cardiac death (SCD) and the assessment of risk factors in prediction models have not been evaluated in women with coronary artery disease (CAD). We sought to evaluate the incidence of SCD as well as its risk factors and their predictive accuracy among a population of women with CAD.</AbstractText><AbstractText Label="METHODS" NlmCategory="METHODS">The Heart and Estrogen/progestin Replacement Study evaluated the effects of hormone replacement therapy on cardiovascular events among 2763 postmenopausal women with CAD. Sudden cardiac death was defined as death resulting from a cardiac origin that occurred within 1 hour of symptom onset. The associations between candidate predictor variables and SCD were evaluated in a Cox proportional hazards model. The C-index was used to compare the predictive value of the clinical risk factors with left ventricular ejection fraction (LVEF) alone and in combination. The net reclassification improvement was also computed.</AbstractText><AbstractText Label="RESULTS" NlmCategory="RESULTS">Over a mean follow-up of 6.8 years, SCD comprised 136 of the 254 cardiac deaths. The annual SCD event rate was 0.79% (95% confidence interval, 0.67-0.94). The following variables were independently associated with SCD in the multivariate model: myocardial infarction, heart failure, an estimated glomerular filtration rate of less than 40 mL/min/1.73 m(2), atrial fibrillation, physical inactivity, and diabetes. The incidences of SCD among women with 0 (n = 683), 1 (n = 1224), 2 (n = 610), and 3 plus (n = 246) risk factors at baseline were 0.3%, 0.5%, 1.2%, and 2.9% per year, respectively. The combination of clinical risk factors and LVEF (C-index, 0.681) were better predictors of SCD than LVEF alone (C-index, 0.600) and resulted in a net reclassification improvement of 0.20 (P < .001).</AbstractText><AbstractText Label="CONCLUSIONS" NlmCategory="CONCLUSIONS">Sudden cardiac death comprised the majority of cardiac deaths among postmenopausal women with CAD. Independent predictors of SCD, including myocardial infarction, congestive heart failure, an estimated glomerular filtration rate of less than 40 mL/min/1.73 m(2), atrial fibrillation, physical inactivity, and diabetes, improved SCD prediction when they were considered in addition to LVEF.</AbstractText></Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Deo</LastName><ForeName>Rajat</ForeName><Initials>R</Initials><AffiliationInfo><Affiliation>Section of Electrophysiology, Division of Cardiovascular Medicine, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA. Rajat.Deo@uphs.upenn.edu</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Vittinghoff</LastName><ForeName>Eric</ForeName><Initials>E</Initials></Author><Author ValidYN="Y"><LastName>Lin</LastName><ForeName>Feng</ForeName><Initials>F</Initials></Author><Author ValidYN="Y"><LastName>Tseng</LastName><ForeName>Zian H</ForeName><Initials>ZH</Initials></Author><Author ValidYN="Y"><LastName>Hulley</LastName><ForeName>Stephen B</ForeName><Initials>SB</Initials></Author><Author ValidYN="Y"><LastName>Shlipak</LastName><ForeName>Michael G</ForeName><Initials>MG</Initials></Author></AuthorList><Language>eng</Language><GrantList CompleteYN="Y"><Grant><GrantID>R01 HL102090-03</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>K23DK089118</GrantID><Acronym>DK</Acronym><Agency>NIDDK NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>K23 DK089118</GrantID><Acronym>DK</Acronym><Agency>NIDDK NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>KL2 RR024132</GrantID><Acronym>RR</Acronym><Agency>NCRR NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>R01 HL102090-02</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>R01 HL102090</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant></GrantList><PublicationTypeList><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D052061">Research Support, N.I.H., Extramural</PublicationType></PublicationTypeList><ArticleDate DateType="Electronic"><Year>2011</Year><Month>07</Month><Day>25</Day></ArticleDate></Article><MedlineJournalInfo><Country>United States</Country><MedlineTA>Arch Intern Med</MedlineTA><NlmUniqueID>0372440</NlmUniqueID><ISSNLinking>0003-9926</ISSNLinking></MedlineJournalInfo><CitationSubset>IM</CitationSubset><CommentsCorrectionsList><CommentsCorrections RefType="CommentIn"><RefSource>Arch Intern Med. 2011 Oct 24;171(19):1710-1</RefSource><PMID Version="1">21788537</PMID></CommentsCorrections></CommentsCorrectionsList><MeshHeadingList><MeshHeading><DescriptorName UI="D000368" MajorTopicYN="N">Aged</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D001281" MajorTopicYN="N">Atrial Fibrillation</DescriptorName><QualifierName UI="Q000401" MajorTopicYN="N">mortality</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D003324" MajorTopicYN="N">Coronary Artery Disease</DescriptorName><QualifierName UI="Q000150" MajorTopicYN="N">complications</QualifierName><QualifierName UI="Q000401" MajorTopicYN="Y">mortality</QualifierName><QualifierName UI="Q000503" MajorTopicYN="N">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D016757" MajorTopicYN="N">Death, Sudden, Cardiac</DescriptorName><QualifierName UI="Q000453" MajorTopicYN="Y">epidemiology</QualifierName><QualifierName UI="Q000209" MajorTopicYN="Y">etiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D048909" MajorTopicYN="N">Diabetes Complications</DescriptorName><QualifierName UI="Q000401" MajorTopicYN="N">mortality</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D015914" MajorTopicYN="N">Estrogen Replacement Therapy</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005260" MajorTopicYN="N">Female</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005919" MajorTopicYN="N">Glomerular Filtration Rate</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D006333" MajorTopicYN="N">Heart Failure</DescriptorName><QualifierName UI="Q000401" MajorTopicYN="N">mortality</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D006801" MajorTopicYN="N">Humans</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D008875" MajorTopicYN="N">Middle Aged</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D009043" MajorTopicYN="N">Motor Activity</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D015337" MajorTopicYN="N">Multicenter Studies as Topic</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D015999" MajorTopicYN="N">Multivariate Analysis</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D009203" MajorTopicYN="N">Myocardial Infarction</DescriptorName><QualifierName UI="Q000401" MajorTopicYN="N">mortality</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D017698" MajorTopicYN="N">Postmenopause</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D011237" MajorTopicYN="N">Predictive Value of Tests</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D016016" MajorTopicYN="Y">Proportional Hazards Models</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D016032" MajorTopicYN="N">Randomized Controlled Trials as Topic</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D018570" MajorTopicYN="N">Risk Assessment</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D012307" MajorTopicYN="N">Risk Factors</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D012680" MajorTopicYN="N">Sensitivity and Specificity</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D013318" MajorTopicYN="N">Stroke Volume</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D014481" MajorTopicYN="N" Type="Geographic">United States</DescriptorName><QualifierName UI="Q000453" MajorTopicYN="N">epidemiology</QualifierName></MeshHeading></MeshHeadingList><CoiStatement>The authors do not have any conflicts of interest.</CoiStatement></MedlineCitation><PubmedData><History><PubMedPubDate PubStatus="entrez"><Year>2011</Year><Month>7</Month><Day>27</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="pubmed"><Year>2011</Year><Month>7</Month><Day>27</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="medline"><Year>2011</Year><Month>12</Month><Day>13</Day><Hour>0</Hour><Minute>0</Minute></PubMedPubDate></History><PublicationStatus>ppublish</PublicationStatus><ArticleIdList><ArticleId IdType="pubmed">21788534</ArticleId><ArticleId IdType="mid">NIHMS370555</ArticleId><ArticleId IdType="pmc">PMC3547327</ArticleId><ArticleId IdType="doi">10.1001/archinternmed.2011.328</ArticleId><ArticleId IdType="pii">archinternmed.2011.328</ArticleId></ArticleIdList><ReferenceList><Reference><Citation>Lloyd-Jones D, Adams R, Carnethon M, et al. 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Eur Heart J. 2006;27(17):2099–2140.</Citation><ArticleIdList><ArticleId IdType="pubmed">16923744</ArticleId></ArticleIdList></Reference></ReferenceList></PubmedData></PubmedArticle><PubmedArticle><MedlineCitation Status="MEDLINE" Owner="NLM"><PMID Version="1">21786588</PMID><DateCompleted><Year>2011</Year><Month>08</Month><Day>17</Day></DateCompleted><DateRevised><Year>2011</Year><Month>07</Month><Day>26</Day></DateRevised><Article PubModel="Print"><Journal><ISSN IssnType="Print">0025-8075</ISSN><JournalIssue CitedMedium="Print"><Issue>3</Issue><PubDate><Year>2011</Year><Season>May-Jun</Season></PubDate></JournalIssue><Title>Meditsinskaia tekhnika</Title><ISOAbbreviation>Med Tekh</ISOAbbreviation></Journal>[Assessment of RR-intervalogram instability]. | To our knowledge, the risk of sudden cardiac death (SCD) and the assessment of risk factors in prediction models have not been evaluated in women with coronary artery disease (CAD). We sought to evaluate the incidence of SCD as well as its risk factors and their predictive accuracy among a population of women with CAD.</AbstractText>The Heart and Estrogen/progestin Replacement Study evaluated the effects of hormone replacement therapy on cardiovascular events among 2763 postmenopausal women with CAD. Sudden cardiac death was defined as death resulting from a cardiac origin that occurred within 1 hour of symptom onset. The associations between candidate predictor variables and SCD were evaluated in a Cox proportional hazards model. The C-index was used to compare the predictive value of the clinical risk factors with left ventricular ejection fraction (LVEF) alone and in combination. The net reclassification improvement was also computed.</AbstractText>Over a mean follow-up of 6.8 years, SCD comprised 136 of the 254 cardiac deaths. The annual SCD event rate was 0.79% (95% confidence interval, 0.67-0.94). The following variables were independently associated with SCD in the multivariate model: myocardial infarction, heart failure, an estimated glomerular filtration rate of less than 40 mL/min/1.73 m(2), atrial fibrillation, physical inactivity, and diabetes. The incidences of SCD among women with 0 (n = 683), 1 (n = 1224), 2 (n = 610), and 3 plus (n = 246) risk factors at baseline were 0.3%, 0.5%, 1.2%, and 2.9% per year, respectively. The combination of clinical risk factors and LVEF (C-index, 0.681) were better predictors of SCD than LVEF alone (C-index, 0.600) and resulted in a net reclassification improvement of 0.20 (P < .001).</AbstractText>Sudden cardiac death comprised the majority of cardiac deaths among postmenopausal women with CAD. Independent predictors of SCD, including myocardial infarction, congestive heart failure, an estimated glomerular filtration rate of less than 40 mL/min/1.73 m(2), atrial fibrillation, physical inactivity, and diabetes, improved SCD prediction when they were considered in addition to LVEF.</AbstractText> |
14,987 | A plea for the wider use of CRT-P in candidates for cardiac resynchronisation therapy. | Spectacular developments have taken place, in the last 10 years, in the device-based management of heart failure (HF). Patients presenting with chronic HF may benefit from a device implanted with a view to: (1) resynchronise the pump function of a discoordinated failing heart or (2) prevent sudden arrhythmic death by automatic cardioversion or defibrillation. This "point-of-view" article reviews the large amount of information gathered in the past 10 years on the use of cardiac resynchronisation therapy (CRT), with or without cardioverter defibrillator (ICD), and puts in perspective the advisability of using one, the other or both treatments in distinct patient subsets. There is currently no strong scientific evidence supporting the systematic implantation of CRT-ICD (CRT-D) instead of CRT pacemakers (CRT-P). Plain common sense should limit the prescription of these costly and complicated devices to patients in need of secondary prevention of ventricular arrhythmias or, for primary prevention, in younger patients without major concomitant illnesses. The preferential choice of CRT-P for the remainder of ambulatory patients in New York Heart Association (NYHA) functional class III or IV is currently acceptable. Because of insufficient data regarding the performance of CRT-P in patients presenting in NYHA functional class I or II, CRT-D is currently the device of choice for this sub-population. |
14,988 | Paralytic ileus associated with use of diltiazem. | A case of paralytic ileus in a patient receiving oral diltiazem therapy for atrial fibrillation is reported.</AbstractText>A 64-year-old man with a history of multiple serious comorbidities, poly-pharmacy, and a recent hospital stay for acute cardiac problems was readmitted to the hospital for gastrointestinal (GI) bleeding. On day 2 of the readmission, he suffered a myocardial infarction complicated by atrial fibrillation with a rapid ventricular response. After initial treatment with oral metoprolol for ventricular rate control was discontinued (due to ineffective rate control and patient complaints of respiratory symptoms), oral diltiazem hydrochloride therapy (30 mg every six hours) was initiated on day 7; the dose was adjusted to a maximum of 120 mg every six hours on day 10. On day 12, the patient complained of nausea, abdominal pain and tenderness, and infrequent bowel movements; imaging studies on day 13 indicated paralytic ileus. Pursuant to a surgical consultation, a nasogastric tube was inserted and nothing was given by mouth except medications. After initial improvement of the GI symptoms, the feeding tube was removed; however, the symptoms worsened over the next two to three days, requiring reinsertion of the tube on day 16. On day 18, after other potential causes of ileus were ruled out, diltiazem therapy was withdrawn. The man experienced rapid symptomatic improvement, with no further GI symptoms, and was discharged four days later.</AbstractText>A 64-year-old man receiving high-dose diltiazem to treat atrial fibrillation developed paralytic ileus, which quickly resolved after the medication was discontinued.</AbstractText> |
14,989 | Dynamic ventricular overdrive stimulation in atrial fibrillation: effects on ventricular rate irregularity, ventricular pacing, and fusion beats. | In pacemaker patients with preserved atrio-ventricular (AV) conduction, atrial fibrillation (AF) can lead to symptomatic ventricular rate irregularity and loss of ventricular stimulation. We tested if dynamic ventricular overdrive (DVO) as a potentially pacemaker-integrated algorithm could improve both aspects.</AbstractText>Different settings of DVO and ventricular-ventricular-inhibited-pacing (VVI) with different base rates were tested in two consecutive phases during electrophysiological studies for standard indications. Mean heart rate (HR), HR irregularity and percentage of ventricular pacing were evaluated. A fusion index (FI) indicative of the proportion of fusion beats was calculated for each stimulation protocol. Dynamic ventricular overdrive from the right ventricular apex was acutely applied in 38 patients (11 females, mean age 62.1 ± 11.5 years) with sustained AF and preserved AV conduction. Dynamic ventricular overdrive at LOW/MEDIUM setting increased the amount of ventricular pacing compared with VVI pacing at 60, 70, and 80 beats per minute (bpm; to 81/85% from 11, 25, and 47%, respectively; P < 0.05). It also resulted in a maximum decrease in interval differences (to 48 ± 18 ms from 149 ± 28, 117 ± 38, and 95 ± 46 ms, respectively; P < 0.05) and fusion (to 0.13 from 0.41, 0.42, and 0.36, respectively; P < 0.05) compared with VVI pacing at 60, 70, and 80 bpm. However, the application of DVO resulted in a significant increase in HR compared with intrinsic rhythm and VVI pacing at 80 bpm (to 97 bpm from 89 and 94 bpm, respectively; P < 0.05).</AbstractText>Dynamic ventricular overdrive decreases HR irregularity and increases ventricular pacing rate compared with VVI pacing at fixed elevated base rates and spontaneous rhythm. Fusion index might help to refine information on pacing percentages provided by device counters.</AbstractText> |
14,990 | Frequency of stroke and embolism in left ventricular hypertrabeculation/noncompaction. | Left ventricular hypertrabeculation/noncompaction (LVHT/NC) is associated with stroke or embolism (S/E). The aim of this retrospective study was to assess the rate, risk factors, and cause of S/E in patients with LVHT/NC. The medical records of patients with LVHT/NC were retrospectively screened for S/E. For stroke classification, the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria were applied, and for peripheral embolism, angiographic findings were used. Baseline clinical, echocardiographic, and electrocardiographic data were compared between patients with and without S/E. In 22 of 144 patients (15%), stroke (n = 21) or peripheral embolism (n = 1) had occurred. The cause of S/E was cardioembolic (n = 14), atherosclerotic (n = 5), or undetermined (n = 3). S/E occurred before (n = 14) and after (n = 8) the diagnosis of LVHT/NC. Only mean age (60 vs 53 years, p <0.05) and the prevalence of hypertension (32% vs 59%, p <0.05) were higher in patients with S/E than in those without S/E. Among patients with cardioembolic S/E, 13 of 14 had either atrial fibrillation (AF) or systolic dysfunction, and AF as well as systolic dysfunction were found in 4 of 14 patients. In conclusion, S/E in patients with LVHT/NC is not always cardioembolic but may also have an atherosclerotic cause. In the absence of AF or left ventricular systolic dysfunction, cardioembolic S/E is rare in patients with LVHT/NC. These findings suggest that patients with LVHT/NC with systolic dysfunction or AF should receive oral anticoagulation as primary prophylaxis against S/E. |
14,991 | QT Prolongation and Life Threatening Ventricular Tachycardia in a Patient Injected With Intravenous Meperidine (Demerol®). | QT prolongation is a serious adverse drug effect, which is associated with an increased risk of Torsade de pointes and sudden death. Many drugs, including both cardiac and non-cardiac drugs, have been reported to cause prolongation of QT interval. Although meperidine has not been considered proarrhythmic, we present a unique case of a 16-year-old boy without an underlying cardiac disease, who developed polymorphic ventricular tachycardia, ventricular fibrillation and QT prolongation after an intravenous meperidine injection. He had no mutation in long QT syndrome genes (KCNQ1, KCNH2, and SCN5A), but single nucleotide polymorphisms were reported, including H558R in SCNA5A and K897T in KCNH2. |
14,992 | Predictors of long-term adverse outcomes in elderly patients over 80 years hospitalized with heart failure. - A report from the Japanese Cardiac Registry of Heart Failure in Cardiology (JCARE-CARD)-. | Aging is associated with adverse outcomes in patients with cardiac diseases. Whether elderly patients hospitalized with heart failure (HF) had increased risks for mortality and rehospitalization compared with younger patients during the long-term follow-up was examined. The predictors of these adverse outcomes were also identified.</AbstractText>The Japanese Cardiac Registry of Heart Failure in Cardiology (JCARE-CARD) studied prospectively the characteristics and treatments in a broad sample of 2,675 patients hospitalized with worsening HF and the outcomes were followed up. The majority of elderly patients were female, had lower body mass index (BMI), a higher rate of ischemic, valvular, and hypertensive heart disease as etiologies of HF, a lower estimated glomerular filtration rate (eGFR), lower hemoglobin, and higher left ventricular ejection fraction values. Even after adjustment for covariates, the elderly patients were associated with higher risks of adverse outcomes. The predictors for all-cause death were: lower eGFR, lower BMI, male sex, sustained ventricular tachycardia or fibrillation (VT/VF), and the use of diuretics at discharge.</AbstractText>Among patients hospitalized with HF, elderly patients had a worse prognosis than younger patients. Lower eGFR, lower BMI, male sex, sustained VT/VF, and diuretic use were independent predictors for all-cause death in these patients with higher risk.</AbstractText> |
14,993 | Primary prevention implantable cardioverter defibrillator recipients: the need for defibrillator back-up after an event-free first battery service-life. | In primary prevention implantable cardioverter defibrillator (ICD) patients, the relatively low incidence of ventricular arrhythmias (VA) combined with the limited battery service-life potentially results in a large group of patients who have had no benefit of the ICD during first service-life. Data on the occurrence of VA after device replacement remain scarce. The purpose of this study was to give clinicians better insight in the dilemma whether or not to replace an ICD after an event-free first battery service-life.</AbstractText>All patients treated with an ICD for primary prevention who had a replacement because of battery depletion and who did not receive appropriate therapy before device replacement were included in this analysis. Of 154 primary prevention ICD patients needing replacement because of battery depletion, 114 (74%) patients (mean age 61 ± 11 years, 80% male) had not received appropriate ICD therapy for VA. Follow-up was 71 ± 24 months after the initial implantation and 25 ± 21 months after device replacement. Following replacement, 3-year cumulative incidence of appropriate therapy in response to ventricular tachycardia or ventricular fibrillation was 14% (95% CI 5-22%).</AbstractText>The majority of primary prevention ICD patients do not experience VA during first battery service-life. However, a substantial part of these patients does experience appropriate ICD therapy after replacement.</AbstractText>© 2011 Wiley Periodicals, Inc.</CopyrightInformation> |
14,994 | [Remote monitoring and follow up of implantable cardioverter defibrillators and cardiac resynchronization therapy devices]. | The implantable cardiac devices like regular pacemaker, cardiac resynchronization therapy (CRT) automatic implantable defibrillators (ICD) and CRT associate with ICD (CRTD) are now being used frequently. Patient visits to pacemaker and ICD clinics for review and monitoring, has increases significantly. We present the experience of monitoring via satellite of patients with implantable cardiac devices in Mexico.</AbstractText>Eighteen patients were selected from the arrhythmia Service Cardiac Electrophysiology and Stimulation of High Specialty Medical Unit (UMAE) of Specialties Hospital Dr. Antonio Fraga Mouret. National Medical Center (NMC) La Raza Mexican Social Security Institute (IMSS), who had a device (CRT, ICD y CRT-D) that is able to send information through the BIOTRONIK Home Monitoring system, from March 2006, to March 2009.</AbstractText>We obtained 4,980 transmissions as reports and 149 alerts recorded events, of which 50 were in ventricular fibrillation, 14 in ventricular tachycardia, frequent ventricular extra systoles exceeded by the range allowed in one hour were 25, electrograms default 26; and atrial fibrillation at 11.</AbstractText>The monitoring system via satellite is reliable and useful diagnostic tool, which permits early detection, opportune treatment and effective monitoring of implantable cardiac devices.</AbstractText> |
14,995 | Clinical and cardiac features of patients with subarachnoid haemorrhage presenting with out-of-hospital cardiac arrest. | Subarachnoid haemorrhage (SAH) is known as one of the aetiologies of out-of-hospital cardiac arrest (OHCA). However, the mechanisms of circulatory collapse in these patients have remained unclear.</AbstractText>We examined 244 consecutive OHCA patients transferred to our emergency department. Head computed tomography was performed on all patients and revealed the existence of SAH in 14 patients (5.9%, 10 females). Among these, sudden collapse was witnessed in 7 patients (50%). On their initial cardiac rhythm, all 14 patients showed asystole or pulseless electrical activity, but no ventricular fibrillation (VF). Return of spontaneous circulation (ROSC) was obtained in 10 of the 14 patients (14.9% of all ROSC patients) although all resuscitated patients died later. The ROSC rate in patients with SAH (71%) was significantly higher than that of patients with either other types of intracranial haemorrhage (25%, n=2/8) or presumed cardiovascular aetiologies (22%, n=23/101) (p<0.01). On electrocardiograms, ST-T abnormalities and/or QT prolongation were found in all 10 resuscitated patients. Despite their electrocardiographic abnormalities, only 3 patients showed echocardiographic abnormalities.</AbstractText>The frequency of SAH in patients with all causes of OHCA was about 6%, and in resuscitated patients was about 15%. The initial cardiac rhythm revealed no VF even though half had a witnessed arrest. A high ROSC rate was observed in patients with SAH, although none survived to hospital discharge.</AbstractText>Copyright © 2011. Published by Elsevier Ireland Ltd.</CopyrightInformation> |
14,996 | Sarcolemmal KATP channel modulators and cardiac arrhythmias. | Cardiac atrial and ventricular arrhythmias are major causes of mortality and morbidity. Ischemic heart disease is the most common cause underlying 1) the development of ventricular fibrillation that results in sudden cardiac death and 2) atrial fibrillation that can lead to heart failure and stroke. Current pharmacological agents for the treatment of ventricular and atrial arrhythmias exhibit limited effectiveness and many of these agents can cause serious adverse effects - including the provocation of lethal ventricular arrhythmias. Sarcolemmal ATP-sensitive potassium channels (sarcK(ATP)) couple cellular metabolism to membrane excitability in a wide range of tissues. In the heart, sarcK(ATP) are activated during metabolic stress including myocardial ischemia, and both the opening of sarcK(ATP) and mitochondrial K(ATP) channels protect the ischemic myocardium via distinct mechanisms. Myocardial ischemia leads to a series of events that promote the generation of arrhythmia substrate eventually resulting in the development of life-threatening arrhythmias. In this review, the possible mechanisms of the anti- and proarrhythmic effects of sarcK(ATP) modulation as well as the influence of pharmacological K(ATP) modulators are discussed. It is concluded that in spite of the significant advances made in this field, the possible cardiovascular therapeutic utility of current sarcK(ATP) channel modulators is still hampered by the lack of chamber-specific selectivity. However, recent insights into the chamber-specific differences in the molecular composition of sarcKATP in addition to already existing cardioselective sarcK(ATP) channel modulators with sarcK(ATP) isoform selectivity holds the promise for the future development of pharmacological strategies specific for a variety of atrial and ventricular arrhythmias. |
14,997 | Cardiac calmodulin kinase: a potential target for drug design. | Therapeutic strategy for cardiac arrhythmias has undergone a remarkable change during the last decades. Currently implantable cardioverter defibrillator therapy is considered to be the most effective therapeutic method to treat malignant arrhythmias. Some even argue that there is no room for antiarrhythmic drug therapy in the age of implantable cardioverter defibrillators. However, in clinical practice, antiarrhythmic drug therapies are frequently needed, because implantable cardioverter defibrillators are not effective in certain types of arrhythmias (i.e. premature ventricular beats or atrial fibrillation). Furthermore, given the staggering cost of device therapy, it is economically imperative to develop alternative effective treatments. Cardiac ion channels are the target of a number of current treatment strategies, but therapies based on ion channel blockers only resulted in moderate success. Furthermore, these drugs are associated with an increased risk of proarrhythmia, systemic toxicity, and increased defibrillation threshold. In many cases, certain ion channel blockers were found to increase mortality. Other drug classes such as ßblockers, angiotensin-converting enzyme inhibitors, aldosterone antagonists, and statins appear to have proven efficacy for reducing cardiac mortality. These facts forced researchers to shift the focus of their research to molecular targets that act upstream of ion channels. One of these potential targets is calcium/calmodulin-dependent kinase II (CaMKII). Several lines of evidence converge to suggest that CaMKII inhibition may provide an effective treatment strategy for heart diseases. (1) Recent studies have elucidated that CaMKII plays a key role in modulating cardiac function and regulating hypertrophy development. (2) CaMKII activity has been found elevated in the failing hearts from human patients and animal models. (3) Inhibition of CaMKII activity has been shown to mitigate hypertrophy, prevent functional remodeling and reduce arrhythmogenic activity. In this review, we will discuss the structural and functional properties of CaMKII, the modes of its activation and the functional consequences of CaMKII activity on ion channels. |
14,998 | Nifekalant in the treatment of life-threatening ventricular tachyarrhythmias. | The aim of the present study is to review the literature and discuss nifekalant's potential use as a first aid drug in an emergency care setting. The PubMed database was used to identify papers, using keywords nifekalant, MS-551, amiodarone and lidocaine. Nifekalant hydrochloride, formally known as MS-551, is a class III antiarrhythmic agent which acts only by increasing the time course of myocardial repolarization. It was developed and is currently being used only in Japan for the treatment of ventricular tachyarrhythmias. It is a non-selective K(+) channel blocker without any β-blocking actions. Administration of nifekalant suppressed sustained ventricular tachyarrhythmias in acute coronary syndrome patients, and in cardiac arrest victims as well as during or after cardiac surgery. The major adverse effect of nifekalant is QT interval prolongation and occurrence of torsades de pointes which requires frequent monitoring of the QT interval during nifekalant infusion with adequate dose adjustment. Nifekalant is a possible effective antiarrhythmic agent for refractory ventricular tachyarrhythmias. Further clinical studies are required before nifekalant is routinely used in the emergency care setting. |
14,999 | Efficacy of catheter ablation in patients with an electrical storm. | Electrical storm (ES) is a life-threatening condition requiring prompt and effective therapy. This may be achieved by the use of catheter ablation.</AbstractText>To assess safety and efficacy of catheter ablation in patients with ES.</AbstractText>We performed 28 ablation procedures from February 2006 to May 2010 due to ES in 24 patients (21 men, 3 women, aged 62.5 ± 7.8 years). Eighteen patients had a history of myocardial infarction, 2 - dilated cardiomyopathy, 2 - hypertrophic cardiomyopathy (one also had myocardial infarction), 1 - spongiform cardiomyopathy, 1 - heart failure after aortic valve replacement and 1 - myocarditis. The mean value of ejection fraction was 27.3 ± 6.5% (15-40%). Procedures were performed using the CARTO system. Two patients after an endocardial map had also epicardial mapping performed and one of these patients underwent epicardial cryoablation. The other one underwent a radiofrequency catheter ablation.</AbstractText>During the follow-up period of 27.8 ± 15.9 months 16 (66%) patients had no ventricular tachycardia (VT)/ventricular fibrillation (VF) episodes. Sporadic VT episodes were observed in 3 patients. Recurrence of ES occurred in 3 (12%) patients and 3 (12%) patients died during the follow-up due to the progression of heart failure.</AbstractText>1. Ablation of ventricular arrhythmias in the course of ES in patients with organic heart disease is safe and effective, and probably improves their prognosis. 2. After ablation, some patients have adequate interventions of implantable cardioverter-defibrillator due to progression of the disease. 3. The method does not prevent haemodynamic mortality.</AbstractText> |
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