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12,400 | Evaluation of the safety and effectiveness of the CryoMedix cryoablation catheter system for the treatment of atrial flutter and fibrillation. | Catheter ablation of atrial flutter and fibrillation (AFL and AF) has typically been performed with radiofrequency energy. Cryoablation has recently been used for AF and AFL, but its success has been limited by the nadir temperature achievable using nitrous oxide as a refrigerant. In this study, a novel approach allowing for use of a liquid refrigerant capable of achieving lower nadir temperatures was tested in a canine model with cavo-tricuspid isthmus (CTI) and left atrial (LA) ablation.</AbstractText>In six dogs, under general anesthesia, standard catheters were placed in the coronary sinus and right ventricular apex, and the CryoMedix cryoablation catheter (CAC) in the right (CTI) and left atrium (for ablation, across the LA roof, mitral isthmus, and LA septum). Double-freezes up to 2 min each were performed, with a 30-s thaw cycle between freezes. Ablated areas were subsequently grossly inspected and photographed and tissues fixed in formalin for histologic analysis to determine if the lesions were contiguous and transmural. In all animals, long linear (from 4-8 cm) transmural atrial lesions were observed on gross and histological examination in the left atrial roof, septum and mitral isthmus, and across the cavo-trisucpid isthmus. In all animals, bi-directional cavo-tricuspid isthmus block was observed after ablation, during pacing from the coronary sinus ostium and low lateral right atrium, respectively. Up to 50% thickness lesions were observed in the right ventricle below the tricuspid valve in all animals. There were no acute complications noted in any animals.</AbstractText>The CAC system produces extremely negative freezing temperatures, significantly lower than those reported for nitrous oxide based systems. The CTI was easily ablated with the CAC system, producing bi-directional conduction block, suggesting a potential role for the system in the treatment of isthmus-dependent atrial flutter. Transmural LA lesions were also produced with the CAC system, suggesting a potential role in treating AF.</AbstractText> |
12,401 | A support vector machine for predicting defibrillation outcomes from waveform metrics. | Algorithms to predict shock success based on VF waveform metrics could significantly enhance resuscitation by optimising the timing of defibrillation.</AbstractText>To investigate robust methods of predicting defibrillation success in VF cardiac arrest patients, by using a support vector machine (SVM) optimisation approach.</AbstractText>Frequency-domain (AMSA, dominant frequency and median frequency) and time-domain (slope and RMS amplitude) VF waveform metrics were calculated in a 4.1Y window prior to defibrillation. Conventional prediction test validity of each waveform parameter was conducted and used AUC>0.6 as the criterion for inclusion as a corroborative attribute processed by the SVM classification model. The latter used a Gaussian radial-basis-function (RBF) kernel and the error penalty factor C was fixed to 1. A two-fold cross-validation resampling technique was employed.</AbstractText>A total of 41 patients had 115 defibrillation instances. AMSA, slope and RMS waveform metrics performed test validation with AUC>0.6 for predicting termination of VF and return-to-organised rhythm. Predictive accuracy of the optimised SVM design for termination of VF was 81.9% (± 1.24 SD); positive and negative predictivity were respectively 84.3% (± 1.98 SD) and 77.4% (± 1.24 SD); sensitivity and specificity were 87.6% (± 2.69 SD) and 71.6% (± 9.38 SD) respectively.</AbstractText>AMSA, slope and RMS were the best VF waveform frequency-time parameters predictors of termination of VF according to test validity assessment. This a priori can be used for a simplified SVM optimised design that combines the predictive attributes of these VF waveform metrics for improved prediction accuracy and generalisation performance without requiring the definition of any threshold value on waveform metrics.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,402 | Shockable rhythms and defibrillation during in-hospital pediatric cardiac arrest. | To analyze the results of cardiopulmonary resuscitation (CPR) that included defibrillation during in-hospital cardiac arrest (IH-CA) in children.</AbstractText>A prospective multicenter, international, observational study on pediatric IH-CA in 12 European and Latin American countries, during 24 months. Data from 502 children between 1 month and 18 years were collected using the Utstein template. Patients with a shockable rhythm that was treated by electric shock(s) were included. The primary endpoint was survival at hospital discharge. Univariate logistic regression analysis was performed to find outcome factors.</AbstractText>Forty events in 37 children (mean age 48 months, IQR: 7-15 months) were analyzed. An underlying disease was present in 81.1% of cases and 24.3% had a previous CA. The main cause of arrest was a cardiac disease (56.8%). In 17 episodes (42.5%) ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) was the first documented rhythm, and in 23 (57.5%) it developed during CPR efforts. In 11 patients (27.5%) three or more shocks were needed to achieve defibrillation. Return of spontaneous circulation (ROSC) was obtained in 25 cases (62.5%), that was sustained in 20 (50.0%); however only 12 children (32.4%) survived to hospital discharge. Children with VF/pVT as first documented rhythm had better sustained ROSC (64.7% vs. 39.1%, p=0.046) and survival to hospital discharge rates (58.8% vs. 21.7%, p=0.02) than those with subsequent VF/pVT. Survival rate was inversely related to duration of CPR. Clinical outcome was not related to the cause or location of arrest, type of defibrillator and waveform, energy dose per shock, number of shocks, or cumulative energy dose, although there was a trend to better survival with higher doses per shock (25.0% with <2Jkg(-1), 43.4% with 2-4Jkg(-1) and 50.0% with >4Jkg(-1)) and worse with higher number of shocks and cumulative energy dose.</AbstractText>The termination of pediatric VF/pVT in the IH-CA setting is achieved in a low percentage of instances with one electrical shock at 4Jkg(-1). When VF/pVT is the first documented rhythm, the results of defibrillation are better than in the case of subsequent VF/pVT. No clear relationship between defibrillation protocol and ROSC or survival has been observed. The optimal pediatric defibrillation dose remains to be determined; therefore current resuscitation guidelines cannot be considered evidence-based, and additional research is needed.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,403 | Selective inhibition of late sodium current suppresses ventricular tachycardia and fibrillation in intact rat hearts. | Enhanced late inward Na current (INa-L) modulates action potential duration (APD) and plays a key role in the genesis of early afterdepolarizations (EADs) and delayed afterdepolarizations (DADs) and triggered activity.</AbstractText>The purpose of this study was to define the influence of selective block of INa-L on EAD- and DAD-mediated triggered ventricular tachycardia (VT) and ventricular fibrillation (VF) in intact hearts using (GS967), a selective and potent (IC50 = 0.13 ± 0.01 μM) blocker of INa-L.</AbstractText>VT/VF were induced either by local aconitine injection (50 μg) in the left ventricular muscle of adult (3-4 months) male rats (N = 21) or by arterial perfusion of 0.1 mM hydrogen peroxide (H2O2) in aged male rats (24-26 months, N = 16). The left ventricular epicardial surface of the isolated-perfused hearts was optically mapped using fluorescent voltage-sensitive dye, and microelectrode recordings of action potentials were made adjacent to the aconitine injection site. The suppressive and preventive effects of GS967 (1 μM) against EAD/DAD-mediated VT/VF were then determined.</AbstractText>Aconitine induced VT in all 13 hearts studied. Activation map (N = 6) showed that the VT was initiated by a focal activity arising from the aconitine injection site (cycle length [CL] 84 ± 12) that degenerated to VF (CL 52 ± 8 ms) within a few seconds. VF was maintained by multifocal activity with occasional incomplete reentrant wavefronts. Administration of GS967 suppressed the VT/VF in 10 of 13 hearts (P < .001). Preexposure to GS967 for 15 minutes before aconitine injection prevented initiation of VT/VF in 5 of 8 additional hearts (P < .02). VF reoccurred within 10 minutes on washout of GS967. Microelectrode recordings (N = 7) showed that VT/VF was initiated by EAD- and DAD-mediated triggered activity at CL of 86 ± 14 ms (NS from VT CL) that preceded the VF. GS967 shortened APD, flattened the slope of the dynamic APD restitution curve, and reduced APD dispersion from 42 ± 12 ms to 8 ± 3 ms (P < .01). H2O2 perfusion in eight fibrotic aged hearts promoted EAD-mediated focal VT/VF, which was suppressed by GS967 in five hearts (P < .02).</AbstractText>The selective INa-L blocker GS967 effectively suppresses and prevents aconitine and oxidative stress-induced EADs, DADs, and focal VT/VF. Suppression of EADs, DADs, and reduction of APD dispersion make GS967 a potentially useful antiarrhythmic drug in conditions of enhanced INa-L.</AbstractText>Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,404 | Coxsackie and adenovirus receptor is a modifier of cardiac conduction and arrhythmia vulnerability in the setting of myocardial ischemia. | The aim of this study was to investigate the modulatory effect of the coxsackie and adenovirus receptor (CAR) on ventricular conduction and arrhythmia vulnerability in the setting of myocardial ischemia.</AbstractText>A heritable component in the risk of ventricular fibrillation during myocardial infarction has been well established. A recent genome-wide association study of ventricular fibrillation during acute myocardial infarction led to the identification of a locus on chromosome 21q21 (rs2824292) in the vicinity of the CXADR gene. CXADR encodes the CAR, a cell adhesion molecule predominantly located at the intercalated disks of the cardiomyocyte.</AbstractText>The correlation between CAR transcript levels and rs2824292 genotype was investigated in human left ventricular samples. Electrophysiological studies and molecular analyses were performed using CAR haploinsufficient (CAR⁺/⁻) mice.</AbstractText>In human left ventricular samples, the risk allele at the chr21q21 genome-wide association study locus was associated with lower CXADR messenger ribonucleic acid levels, suggesting that decreased cardiac levels of CAR predispose to ischemia-induced ventricular fibrillation. Hearts from CAR⁺/⁻ mice displayed slowing of ventricular conduction in addition to an earlier onset of ventricular arrhythmias during the early phase of acute myocardial ischemia after ligation of the left anterior descending artery. Expression and distribution of connexin 43 were unaffected, but CAR⁺/⁻ hearts displayed increased arrhythmia susceptibility on pharmacological electrical uncoupling. Patch-clamp analysis of isolated CAR⁺/⁻ myocytes showed reduced sodium current magnitude specifically at the intercalated disk. Moreover, CAR coprecipitated with NaV1.5 in vitro, suggesting that CAR affects sodium channel function through a physical interaction with NaV1.5.</AbstractText>CAR is a novel modifier of ventricular conduction and arrhythmia vulnerability in the setting of myocardial ischemia. Genetic determinants of arrhythmia susceptibility (such as CAR) may constitute future targets for risk stratification of potentially lethal ventricular arrhythmias in patients with coronary artery disease.</AbstractText>Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,405 | Novel insight into the natural history of short QT syndrome. | This study intends to gain further insights into the natural history, the yield of familial and genetic screening, and the arrhythmogenic mechanisms in the largest cohort of short QT syndrome (SQTS) patients described so far.</AbstractText>SQTS is a rare genetic disorder associated with life-threatening arrhythmias, and its natural history is incompletely ascertained.</AbstractText>Seventy-three SQTS patients (84% male; age, 26 ± 15 years; corrected QT interval, 329 ± 22 ms) were studied, and 62 were followed for 60 ± 41 months (median, 56 months).</AbstractText>Cardiac arrest (CA) was the most frequent presenting symptom (40% of probands; range, <1 month to 41 years). The rate of CA was 4% in the first year of life and 1.3% per year between 20 and 40 years; the probability of a first occurrence of CA by 40 years of age was 41%. Despite the male predominance, female patients had a risk profile superimposable to that of men (p = 0.49). The yield of genetic screening was low (14%), despite familial disease being present in 44% of kindreds. A history of CA was the only predictor of recurrences at follow-up (p < 0.0000001). Two patterns of onset of ventricular fibrillation were observed and were reproducible in patients with multiple occurrences of CA. Arrhythmias occurred mainly at rest.</AbstractText>SQTS is highly lethal; CA is often the first manifestation of the disease with a peak incidence in the first year of life. Survivors of CA have a high CA recurrence rate; therefore, implantation of a defibrillator is strongly recommended in this group of patients.</AbstractText>Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,406 | Myocardial extracellular volume expansion and the risk of recurrent atrial fibrillation after pulmonary vein isolation. | This study tested whether myocardial extracellular volume (ECV) is increased in patients with hypertension and atrial fibrillation (AF) undergoing pulmonary vein isolation and whether there is an association between ECV and post-procedural recurrence of AF.</AbstractText>Hypertension is associated with myocardial fibrosis, an increase in ECV, and AF. Data linking these findings are limited. T1 measurements pre-contrast and post-contrast in a cardiac magnetic resonance (CMR) study provide a method for quantification of ECV.</AbstractText>Consecutive patients with hypertension and recurrent AF referred for pulmonary vein isolation underwent a contrast CMR study with measurement of ECV and were followed up prospectively for a median of 18 months. The endpoint of interest was late recurrence of AF.</AbstractText>Patients had elevated left ventricular (LV) volumes, LV mass, left atrial volumes, and increased ECV (patients with AF, 0.34 ± 0.03; healthy control patients, 0.29 ± 0.03; p < 0.001). There were positive associations between ECV and left atrial volume (r = 0.46, p < 0.01) and LV mass and a negative association between ECV and diastolic function (early mitral annular relaxation [E'], r = -0.55, p < 0.001). In the best overall multivariable model, ECV was the strongest predictor of the primary outcome of recurrent AF (hazard ratio: 1.29; 95% confidence interval: 1.15 to 1.44; p < 0.0001) and the secondary composite outcome of recurrent AF, heart failure admission, and death (hazard ratio: 1.35; 95% confidence interval: 1.21 to 1.51; p < 0.0001). Each 10% increase in ECV was associated with a 29% increased risk of recurrent AF.</AbstractText>In patients with AF and hypertension, expansion of ECV is associated with diastolic function and left atrial remodeling and is a strong independent predictor of recurrent AF post-pulmonary vein isolation.</AbstractText>Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,407 | Exercise echocardiography in asymptomatic HCM: exercise capacity, and not LV outflow tract gradient predicts long-term outcomes. | This study sought to assess long-term outcomes in asymptomatic or minimally symptomatic patients with hypertrophic cardiomyopathy (HCM) who underwent exercise echocardiography, without invasive therapies for relief of left ventricular outflow tract (LVOT) obstruction.</AbstractText>Many HCM patients present with LVOT obstruction, mitral regurgitation (MR), and diastolic dysfunction, often requiring invasive therapies for symptomatic relief. However, a significant proportion of truly asymptomatic patients can be closely monitored. In HCM patients, exercise echocardiography has been shown to be a useful assessment of functional capacity and risk stratification.</AbstractText>We included 426 HCM patients (44 ± 14 years; 78% men) undergoing exercise echocardiography, excluding hypertensive heart disease of elderly, ejection fraction <50% and invasive therapy (myectomy or alcohol ablation) during follow-up. Clinical, echocardiographic (LV thickness, LVOT gradient, and MR) and exercise variables (percent of age-sex predicted metabolic equivalents [METs] and heart rate recovery [HRR] at 1 min post-exercise) were recorded. A composite endpoint of death, appropriate internal defibrillator discharge, and admission for congestive heart failure was recorded.</AbstractText>Patients were asymptomatic or minimally symptomatic on history, but 82% of patients achieved <100% of age-sex predicted METs, and 43% had ≥II+ post-stress MR. The mean LV septal thickness, post-exercise LVOT gradient, and HRR were 2.0 ± 0.5 cm, 62 ± 47 mm Hg, and 31 ± 14 beats/min, respectively. During a mean follow-up of 8.7 ± 3 years, there were 52 events (12%). Patients achieving >100% of age-sex predicted METs had 1% event rate versus 12% in those achieving <85%. On stepwise multivariate survival analysis, percent of age-sex predicted METs (hazard ratio [HR]: 0.76; 95% confidence interval [CI]: 0.64 to 0.90), abnormal HRR (HR: 0.89; 95% CI: 0.82 to 0.97), and atrial fibrillation (HR: 2.73; 95% CI: 1.30 to 5.74) (overall, p < 0.001) independently predicted outcomes.</AbstractText>In asymptomatic or minimally symptomatic HCM patients, exercise stress testing provides excellent risk stratification, with a low event rate in patients achieving >100% of predicted METs.</AbstractText>Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,408 | Adjuvant antiarrhythmic therapy in patients with implantable cardioverter defibrillators. | The risk of sudden cardiac death from ventricular fibrillation or ventricular tachycardia in patients with cardiomyopathy related to structural heart disease has been favorably impacted by the wide adaptation of implantable cardioverter defibrillators (ICDs) for both primary and secondary prevention. Unfortunately, after ICD implantation both appropriate and inappropriate ICD therapies are common. ICD shocks in particular can have significant effects on quality of life and disease-related morbidity and mortality. While not indicated for primary prevention of ICD therapies, beta-blockers and antiarrhythmic drugs are a cornerstone for secondary prevention of them. This review will summarize our current understanding of adjuvant antiarrhythmic drug therapy in ICD patients. The review will also discuss the roles of nonantiarrhythmic drug approaches that are used in isolation and in combination with antiarrhythmic drugs to reduce subsequent risk of ICD shocks. |
12,409 | Electrocardiogram pattern recognition and analysis based on artificial neural networks and support vector machines: a review. | Computer systems for Electrocardiogram (ECG) analysis support the clinician in tedious tasks (e.g., Holter ECG monitored in Intensive Care Units) or in prompt detection of dangerous events (e.g., ventricular fibrillation). Together with clinical applications (arrhythmia detection and heart rate variability analysis), ECG is currently being investigated in biometrics (human identification), an emerging area receiving increasing attention. Methodologies for clinical applications can have both differences and similarities with respect to biometrics. This paper reviews methods of ECG processing from a pattern recognition perspective. In particular, we focus on features commonly used for heartbeat classification. Considering the vast literature in the field and the limited space of this review, we dedicated a detailed discussion only to a few classifiers (Artificial Neural Networks and Support Vector Machines) because of their popularity; however, other techniques such as Hidden Markov Models and Kalman Filtering will be also mentioned. |
12,410 | Relation of autonomic and cardiac abnormalities to ventricular fibrillation in a rat model of epilepsy. | Cardiac autonomic, conduction, and structural changes may occur in epilepsy and may contribute to sudden unexpected death in epilepsy (SUDEP), e.g. by increasing the risk for ventricular fibrillation (VF). In a model of chronic seizures in rats, we sought to study (1) cardiac and autonomic derangements that accompany the epileptic state, (2) whether chronically seizing rats experienced more significant cardiac effects after severe acute seizures, and (3) the susceptibility of chronically seizing rats to VF arising from autonomic and hypoxemic changes, which commonly occur during seizures. Sprague-Dawely rats were injected with saline or kainic acid to induce chronic seizures. At 2-3 months or 7-11 months after injection, these rats were studied with both 12-lead electrocardiography (to assess heart rate variability and QT dispersion) and echocardiography under ketamine/xylazine or urethane anesthesia. Hearts were subsequently excised, weighed, and examined histologically. Epileptic rats exhibited decreased vagal tone, increased QT dispersion, and eccentric cardiac hypertrophy without significant cardiac fibrosis, especially at 7-11 months post-injection. Of these three findings, vagal tone was inversely correlated with heart weights. Epileptic rats exhibited diminished systolic function compared to controls after severe acute seizures. However, animals with long-standing chronic seizures were less susceptible to autonomic/hypoxemia-driven VF, and their susceptibility inversely correlated with mean left ventricular wall thickness on histology. On the basis of this model, we conclude that cardiac changes accompany epilepsy and these can lead to significant seizure-associated cardiac performance decreases, but these cardiac changes actually lower the probability of VF. |
12,411 | Arrhythmias and heart failure. | Atrial fibrillation and ventricular tachyarrhythmias are frequently seen in patients with heart failure, and complicate the management of such patients. Both types of arrhythmia lead to increased morbidity and mortality, and often prove to be challenging issues to manage. The many randomized studies that have been performed in patients with these conditions and concomitant heart failure have helped in designing optimal treatment strategies. |
12,412 | [Clinical features and management of complete heart block after transaortic extended septal myectomy in patients with hypertrophic obstructive cardiomyopathy]. | To analyze the clinical features, precaution and management of complete heart block (CHB) after transaortic extended septal myectomy operation (extended Morrow procedure) in patients with hypertrophic obstructive cardiomyopathy (HOCM).</AbstractText>From October 1996 to December 2011, 10[6 men; mean age (45.4 ± 15.8) years, range 13-60 years] out of 160 consecutive HOCM patients underwent extended Morrow procedure developed CHB postoperatively. Their clinical data were retrospectively analyzed. Baseline transthoracic echocardiography showed that the left ventricular outflow tract (LVOT) gradients was from 68 to 149 (105.1 ± 25.9) mm Hg (1 mm Hg = 0.133 kPa), ECG showed right bundle branch block in 5 patients and atrial fibrillation, atrial premature beats or ST-T segment changes in other 5 patients. Besides extended Morrow procedure, concomitant surgical procedures included mitral valve replacement (MVR) in 2 (2/10) and MVR plus coronary artery bypass grafting in another 2 (2/10) patients. Follow-up data were obtained by subsequent clinic visits in outpatient department and telephone interviews.</AbstractText>The in-hospital mortality was 20% (these two patients died of low cardiac output syndrome and multiple organs failure). Four patients underwent MVR simultaneously survived the operation. Postoperative echocardiography demonstrated a reduced LVOT gradient[(13.6 ± 9.7) mm Hg, P < 0.001]. Permanent pacemakers were implanted in all 8 survived patients at 6 days to 7 months after operation. No other severe complications were observed. During follow-up [from 4 to 72 (19.4 ± 22.1) months], there was no death, 1 patient readmitted to our center at 71 months post operation to change the pacemaker because of low voltage of previously implanted pacemaker. Physical capacity and quality of life improved significantly post operation in these 8 patients. The NYHA functional class remained at I-II post operation and during follow up.</AbstractText>CHB is a severe complication after extended Morrow procedure for patients with HOCM and timely permanent pacemaker implantation is mandatory for patients with post procedure CHB.</AbstractText> |
12,413 | [Types and risk factors of arrhythmia on young patients with acute coronary syndrome in Henan province]. | The types and risk factors of arrhythmia were analyzed on acute coronary syndrome (ACS) patients under the age of 44 years who were hospitalized in Henan province between September 2009 to June 2012.</AbstractText>Medical records of eligible patients were obtained from the information system of the First Affiliated Hospital of Zhengzhou University teleconsultation information center. Middle aged and elderly ACS patients who were hospitalized at the same period served as controls. Data on arrhythmia types, blood pressure, thyroid disease, respiratory sleep apnea syndrome, smoking history, history of alcohol consumption, eating habits, family history of early-onset arrhythmia, laboratory tests were analyzed.</AbstractText>(1) Arrhythmia was detected in 110 out of young ACS patients (55%), which was significantly lower than that in the elderly ACS patients (71.05%, P < 0.01). (2) The top three arrhythmias in young ACS patients were: sinus tachycardia (30.50%), the premature ventricular contractions (19.00%), atrial flutter/atrial fibrillation (16.50%). Incidence of sinus tachycardia, atrial flutter/atrial fibrillation were significantly higher while incidence of ventricular tachycardia, ventricular fibrillation, paroxysmal supraventricular tachycardia were significantly lower in young ACS patients than in middle-aged ACS patients (all P < 0.05). The incidence of sinus tachycardia was higher while incidence of ventricular premature accelerated ventricular spontaneous cardiac rhythm, ventricular tachycardia, ventricular fibrillation, non-paroxysmal supraventricular tachycardia, atrial flutter/atrial fibrillation, paroxysmal supraventricular tachycardia, sinus bradycardia, nodal escape, atrioventricular block were significantly lower in young ACS patients than in elderly ACS patients (all P < 0.05). (3) Body mass index, incidence of smoking, coronary three-vessel disease, drinking, eating salty foods, thyroid dysfunction, sleep apnea were significantly higher in youth ACS patients with arrhythmia than in young ACS patients without arrhythmia (all P < 0. 05). (4) Logistic regression analysis found that number of diseased coronary vessels (OR = 24.293), smoking (OR = 1.112) and alcohol consumption (OR = 1.039) were independent risk factor for developing arrhythmia in young ACS patients from Henan province.</AbstractText>The main types of arrhythmia are sinus tachycardia, premature ventricular contractions, atrial flutter/atrial fibrillation and the major risk factors related to the arrhythmia are number of diseased coronary vessels, smoking and alcohol consumption in young ACS patients from Henan province.</AbstractText> |
12,414 | Magnesium: the forgotten electrolyte. | Magnesium (Mg++), Potassium (K+) and Calcium (CA++) are important electrolytes in keeping a stable electrical status. The purpose of this study was to measure them in critically ill patients.</AbstractText>We evaluated the electrolytes in 28 consecutive patients. Eighteen were females and 10 males with mean age of 62 +/- 5 years.</AbstractText>The admission diagnosis in 95% of the cases was congestive heart failure. Sixty-four percent of the patients had subnormal values of Mg++, 53% subnormal values of K+, and 28% subnormal values of CA++. Fourteen percent showed lower values of the three electrolytes and 35% only of Mg++ and K+ concomitantly. Twenty-eight percent showed prolonged QTC interval. All patients with prolonged QTC interval had low Mg++ and K+ levels. Twenty five percent of the patients showed atrial fibrillation, 25% ventricular tachycardia, and 3% junctional tachycardia. The ventricular tachycardia group had more electrolyte abnormalities than those with atrial fibrillation. None of the patients received Mg++ replacement during critical management while 50% received K+ replacement.</AbstractText>This data shows physician overlook the Importance of Mg++ and K+ deficiency in critically ill patients.</AbstractText> |
12,415 | Three cases of corticosteroid therapy triggering ventricular fibrillation in J-wave syndromes. | We describe three cases of J-wave syndrome in which ventricular fibrillation (VF) was probably induced by corticosteroid therapy. The patients involved were being treated with prednisolone for concomitant bronchial asthma. One of the three patients had only one episode of VF during her long follow-up period (14 years). Two patients had hypokalemia during their VF episodes. Corticosteroids have been shown to induce various types of arrhythmia and to modify cardiac potassium channels. We discuss the possible association between corticosteroid therapy and VF in J-wave syndrome based on the cases we have encountered. |
12,416 | Prognostic difference between paroxysmal and non-paroxysmal atrial fibrillation in patients with hypertrophic cardiomyopathy. | The association of atrial fibrillation (AF) with sudden death and the difference in prognostic significance between paroxysmal and non-paroxysmal AF remains unclear in patients with hypertrophic cardiomyopathy (HCM). Our aim was to investigate the clinical significance of AF, and to assess the prognostic difference between paroxysmal and non-paroxysmal AF in HCM patients.</AbstractText>The study included 430 HCM patients. Documentation of AF was based on electrocardiograms obtained either after the acute onset of symptoms or fortuitously during routine examination of asymptomatic patients.</AbstractText>AF was detected in 120 patients (27.9%). In the patients with AF, syncope and non-sustained ventricular tachycardia were more frequent and the left atrial dimension was larger. Multivariate analysis showed that AF was an independent determinant of the outcome, including the risk of HCM-related death (adjusted hazard ratio 3.57, p<0.001) and sudden death (adjusted hazard ratio 2.61, p=0.038). When patients with AF were divided into subgroups with paroxysmal AF (n=75) or non-paroxysmal AF (n=45), only paroxysmal AF was identified as an independent determinant of the outcome, including the risk of HCM-related death (adjusted hazard ratio 5.24, p<0.001) and sudden death (adjusted hazard ratio 4.67, p=0.002).</AbstractText>AF is a common supraventricular arrhythmia in HCM and has an adverse influence on the prognosis. In addition, each type of AF had a different clinical impact, with paroxysmal AF being a significant independent determinant of an adverse outcome, including sudden death.</AbstractText>Copyright © 2013 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
12,417 | Prevalence and the long-term prognosis of functional mitral regurgitation in Japanese patients with symptomatic heart failure. | Functional mitral regurgitation (FMR) is a common and critical condition in patients with heart failure (HF); however, the prevalence and clinical outcome of FMR in Japanese real-world clinical practice remain unclear. Within a single hospital-based cohort in the Shinken Database 2004-2011, which comprised all new patients (n = 17,517) who visited the Cardiovascular Institute, we followed symptomatic HF patients. A total of 1,701 patients were included: 104 FMR patients (who had moderate to severe FMR) and 1,597 non-FMR patients (who had none or mild FMR). FMR patients had lower rates of hypertension and dyslipidemia, but higher rates of dilated cardiomyopathy, atrial fibrillation, and New York Heart Association functional class III/IV. FMR patients had higher levels of brain natriuretic peptide and lower left ventricular function. Use of cardiovascular drugs was more common among FMR patients. Kaplan-Meier curves revealed that the incidences of all-cause death, cardiovascular death, and admission for HF were significantly higher in FMR patients. The adjusted Cox regression analysis showed that significant FMR was associated with higher incidences of all-cause death [hazard ratio (HR) 2.179, 95 % confidence interval (CI) 1.266-3.751; P = 0.005], cardiovascular death (HR 2.371, 95 % CI 1.157-4.858; P = 0.018), and admission for HF (HR 1.819, 95 % CI 1.133-2.920; P = 0.013). FMR was common in Japanese symptomatic HF patients and was associated with adverse long-term outcomes. Establishing optimal therapeutic strategies for FMR is warranted. |
12,418 | Electrocardiographic J waves are associated with right ventricular morphology and function: evaluation by cardiac magnetic resonance imaging. | We assessed the relationship between J waves and the ventricular morphology and function using cardiac magnetic resonance imaging (MRI). The 12-lead electrocardiograms (ECGs) of 105 consecutive patients who underwent cardiac MRI were reviewed, and those with signs of arrhythmogenic right ventricular cardiomyopathy, complete left bundle branch block, complete right bundle branch block, or chronic atrial fibrillation, where the J wave is difficult to distinguish, were excluded. The ECGs of the remaining 68 patients were analyzed for the presence of J waves. Ventricular morphologic abnormalities were identified on MRI, based on the largest short-axis diameter in the right and left ventricles (d-RVmax/d-LVmax), the area (a-RVmax/a-LVmax), and the ratio RV/LVmax. The percentage contraction of the RV (PC-RV) was used as a measure of ventricular function. Thirty-two patients (47.0 %) had J waves defined as QRS-ST junction elevation >0.1 mV from baseline in the inferior/lateral leads (J group; 56 ± 15 years; 19 males). Thirty-six patients (53.0 %) did not present J waves (NJ group; 58 ± 15 years; 27 males). The d-RVmax and a-RVmax in the J group were larger than those in the NJ group (41 ± 5.2 vs 36 ± 6.6 mm, P = 0.002 and 14 ± 2.9 vs 12 ± 3.4 cm(2), P = 0.022, respectively). The RV/LVmax ratio in the J group was larger than that in the NJ group (0.83 ± 0.15 vs 0.68 ± 0.15, P < 0.001). The PC-RV in the J group was smaller than that in the NJ group (0.28 ± 0.14 vs 0.36 ± 0.15, P = 0.013). J-wave amplitude was correlated positively with d-RVmax (P = 0.010) and negatively with PC-RV (P = 0.005). These results suggested that J waves are associated with right ventricular morphologic and functional abnormalities. |
12,419 | Effect of sleep apnea and continuous positive airway pressure on cardiac structure and recurrence of atrial fibrillation. | Sleep apnea (SA) is associated with an increased risk of atrial fibrillation (AF). We sought to determine the effect of SA on cardiac structure in patients with AF, whether therapy for SA was associated with beneficial cardiac structural remodelling, and whether beneficial cardiac structural remodelling translated into a reduced risk of recurrence of AF after pulmonary venous isolation (PVI).</AbstractText>A consecutive group of 720 patients underwent a cardiac magnetic resonance study before PVI. Patients with SA (n=142, 20%) were more likely to be male, diabetic, and hypertensive and have an increased pulmonary artery pressure, right ventricular volume, atrial dimensions, and left ventricular mass. Treated SA was defined as duration of continuous positive airway pressure therapy of >4 hours per night. Treated SA patients (n=71, 50%) were more likely to have paroxysmal AF, a lower blood pressure, lower ventricular mass, and smaller left atrium. During a follow-up of 42 months, AF recurred in 245 patients. The cumulative incidence of AF recurrence was 51% in patients with SA, 30% in patients without SA, 68% in patients with untreated SA, and 35% in patients with treated SA. In a multivariable model, the presence of SA (hazard ratio 2.79, CI 1.97 to 3.94, P<0.0001) and untreated SA (hazard ratio 1.61, CI 1.35 to 1.92, P<0.0001) were highly associated with AF recurrence.</AbstractText>Patients with SA have an increased blood pressure, pulmonary artery pressure, right ventricular volume, left atrial size, and left ventricular mass. Therapy with continuous positive airway pressure is associated with lower blood pressure, atrial size, and ventricular mass, and a lower risk of AF recurrence after PVI.</AbstractText> |
12,420 | Electrocardiogram frequency change by extracorporeal blood perfusion in a swine ventricular fibrillation model. | Extracorporeal cardiopulmonary resuscitation (ECPR) refers to the application of extracorporeal blood circulation with oxygenation as a resuscitation tool. The objective of this study is to observe the frequency component changes in the electrocardiogram (ECG) by ECPR during prolonged ventricular fibrillation (VF).</AbstractText>Six swine were prepared as a VF model. Extracorporeal blood circulation with a pulsatile blood pump and oxygenator was set up for the model. ECG signals were measured for 13 min during VF and analyzed using frequency analysis methods. The median frequency (MF), dominant frequency (DF), and amplitude spectrum area (AMSA) were calculated from a spectrogram obtained using short-time Fourier transform (STFT).</AbstractText>MF decreased from 11 Hz at the start to 9 Hz at 2 min after VF and then increased to 11 Hz at 4.5 min after VF. DF started at 7 Hz and increased to 11 Hz within the first min and decreased to 9 Hz at 2 min, then increased to 12 Hz at 4.5 min after VF. Both frequency components decreased gradually from 4.5 min until 10 min after VF. After the oxygenated blood perfusion was initiated, both MF and DF increased remarkably and exceeded 12 and 14 Hz, respectively. Similarly, AMSA decreased gradually for the first 10 min, but increased remarkably and varied beyond 13 mV∙Hz after the oxygenated blood supply started. Remarkable frequency increases in ECG due to the oxygenated blood perfusion during ECPR were observed in the swine VF model.</AbstractText>The ECG frequency analysis during ECPR can give the resuscitation provider important information about the cardiac perfusion status and the appropriateness of the ECPR setup as well as the prediction of defibrillation success.</AbstractText> |
12,421 | Design of the PRINCESS trial: pre-hospital resuscitation intra-nasal cooling effectiveness survival study (PRINCESS). | Therapeutic hypothermia (TH, 32-34°C) has been shown to improve neurological outcome in comatose survivors of out-of-hospital cardiac arrest (OHCA) with ventricular tachycardia or fibrillation. Earlier initiation of TH may increase the beneficial effects. Experimental studies have suggested that starting TH during cardiopulmonary resuscitation (CPR) may further enhance its neuroprotective effects. The aim of this study was to evaluate whether intra-arrest TH (IATH), initiated in the field with trans nasal evaporative cooling (TNEC), would provide outcome benefits when compared to standard of care in patients being resuscitated from OHCA.</AbstractText><AbstractText Label="METHODS/DESIGN" NlmCategory="METHODS">We describe the methodology of a multi-centre, randomized, controlled trial comparing IATH delivered through TNEC device (Rhinochill, Benechill Inc., San Diego, CA, USA) during CPR to standard treatment, including TH initiated after hospital admission. The primary outcome is neurological intact survival defined as cerebral performance category 1-2 at 90 days among those patients who are admitted to the hospital. Secondary outcomes include survival at 90 days, proportion of patients achieving a return to spontaneous circulation (ROSC), the proportion of patients admitted alive to the hospital and the proportion of patients achieving target temperature (<34°C) within the first 4 hours since CA.</AbstractText>This ongoing trial will assess the impact of IATH with TNEC, which may be able to rapidly induce brain cooling and have fewer side effects than other methods, such as cold fluid infusion. If this intervention is found to improve neurological outcome, its early use in the pre-hospital setting will be considered as an early neuro-protective strategy in OHCA.</AbstractText>NCT01400373.</AbstractText> |
12,422 | Hyperthyroidism and cardiovascular complications: a narrative review on the basis of pathophysiology. | Cardiovascular complications are important in hyperthyroidism because of their high frequency in clinical presentation and increased mortality and morbidity risk. The cause of hyperthyroidism, factors related to the patient, and the genetic basis for complications are associated with risk and the basic underlying mechanisms are important for treatment and management of the disease. Besides cellular effects, hyperthyroidism also causes hemodynamic changes, such as increased preload and contractility and decreased systemic vascular resistance causes increased cardiac output. Besides tachyarrythmias, impaired systolic ventricular dysfunction and diastolic dysfunction may cause thyrotoxic cardiomyopathy in a small percentage of the patients, as another high mortality complication. Although the medical literature has some conflicting data about benefits of treatment of subclinical hyperthyroidism, even high-normal thyroid function may cause cardiovascular problems and it should be treated. This review summarizes the cardiovascular consequences of hyperthyroidism with underlying mechanisms. |
12,423 | Left thoracoscopic sympathectomy for cardiac denervation in patients with life-threatening ventricular arrhythmias. | We reported the outcomes of a single-institution experience using video-assisted thoracoscopic left cardiac sympathetic denervation as an adjunctive therapeutic technique in pediatric and young adult patients with life-threatening ventricular arrhythmias.</AbstractText>We conducted a retrospective clinical review of all patients who underwent left cardiac sympathetic denervation by means of video-assisted thoracoscopic surgery at our institution. From August 2000 to December 2011, 24 patients (13 with long QT syndrome, 9 with catecholaminergic polymorphic ventricular tachycardia, and 2 with idiopathic ventricular tachycardia) were identified from the cardiology database and surgical records.</AbstractText>There were no intraoperative complications. The median postoperative length of stay was 2 days (range, 1-32 days). There were no major perioperative complications. Longer-term follow-up was available in 22 of 24 patients at a median follow-up of 28 months (range, 4-131 months). Sixteen (73%) of the 22 patients experienced a marked reduction in their arrhythmia burden, with 12 (55%) becoming completely arrhythmia free after sympathectomy. Six (27%) of the patients were nonresponsive to treatment; each had persistent symptoms at follow-up.</AbstractText>Video-assisted thoracoscopic left cardiac sympathetic denervation can be safely and effectively performed in most patients with life-threatening ventricular arrhythmias. This minimally invasive procedure is a promising adjunctive therapeutic option that achieves a beneficial response in most symptomatic patients. These results support the inclusion of thoracoscopic cardiac sympathetic denervation among the treatment armamentarium in all patients with ventricular arrhythmias refractive to conventional medical therapy.</AbstractText>Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
12,424 | Maze procedure in patients with left ventricular dysfunction. | The risks and benefits of a concomitant Maze procedure for patients with LV dysfunction undergoing major cardiac surgery have not yet been elucidated. This study aimed to evaluate the clinical impacts of the Maze procedure in patients with atrial fibrillation and left ventricular (LV) dysfunction.</AbstractText>Between January 1999 and March 2011, a total of 139 patients (mean age 52.7±12.3 years, 54 females) with valvular atrial fibrillation (AF) and an LV ejection fraction (EF) of 40% or less underwent open heart surgery with (n=77) or without (n=62) a concomitant Maze procedure. We compared adverse outcomes (death and composite of death, thromboembolic events and congestive heart failure [CHF]) during a median follow-up period of 66.0 months (inter-quartile range, 27.5-106.9 months).</AbstractText>Adverse events occurred in 41 patients, including 36 deaths, seven thromboembolic events and eight hospitalizations due to CHF. After adjustment for baseline profiles with the use of propensity scores and inverse probability weighting, patients who had the Maze procedure were at lower risks of death (hazard ratio, 0.39; 95% confidence interval, 0.16-0.93; P=0.033) and composite adverse outcomes (hazard ratio, 0.28; 95% confidence interval, 0.14-0.57; P=0.017) than those not undergoing the Maze procedure. Furthermore, the Maze procedure resulted in superior functional status (P<0.001) and reduced the need for long-term anticoagulation therapy (67.1% vs. 91.2%, P=0.001).</AbstractText>Performing the Maze procedure on patients with valvular AF and LV dysfunction reduced serious adverse outcomes and the need for long-term anticoagulation therapy when compared to cardiac surgery alone without the Maze procedure.</AbstractText>Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,425 | Very prolonged episode of self-terminating ventricular fibrillation in a patient with Brugada syndrome. | We report the case of a very prolonged spontaneous episode of self-terminating ventricular fibrillation in a patient with Brugada syndrome (BrS). The patient first underwent implantation of an internal loop recorder after an episode of prolonged loss of consciousness (several minutes) that was suggestive of a nonarrhythmic cause. After a second episode of prolonged syncope, subsequent interrogation of the loop recorder revealed a very prolonged episode of self-terminating ventricular arrhythmia, lasting 2 minutes and 41 seconds. This short report emphasizes the fact that an arrhythmic cause of syncope should not be ruled out in patients with BrS presenting with very prolonged loss of consciousness. |
12,426 | Predictors of mortality in patients with an implantable cardiac defibrillator: a systematic review and meta-analysis. | Many current predictors of mortality in heart failure (HF) were evaluated before the use of implantable cardioverter defibrillators (ICDs). We conducted a meta-analysis to identify factors associated with mortality in ICD-HF patients.</AbstractText>We searched in MedLine, EMBASE, and CINAHL in May 2012. Two reviewers selected citations that included ambulatory ICD patients and addressed the association between any predictor and mortality using multivariable regression. We meta-analyzed mortality using random-effects models.</AbstractText>Of 10,420 studies reviewed, 72 studies evaluating 63 predictors on 257,692 ICD patients proved eligible. High confidence in estimates was found for age (hazard ratio [HR], 1.45 for 10-year increase; 95% confidence interval [CI], 1.35-1.56), baseline glomerular filtration rate (HR, 1.25 for 15-mL/min decrease; 95% CI, 1.15-1.35), chronic obstructive pulmonary disease (HR, 1.54; 95% CI, 1.38-1.71), diabetes (HR, 1.56; 95% CI, 1.37-1.79), peripheral vascular disease (HR, 1.43; 95% CI, 1.2-1.72), left ventricular ejection fraction (HR, 0.77 for 10% increase; 95% CI, 0.73-0.83), and appropriate or inappropriate ICD shocks (HR, 2.34; 95% CI 1.59-3.44) New York Heart Association class, atrial fibrillation, and congestive HF were strongly associated with mortality but the confidence in estimates was low. Ischemic cardiomyopathy and male sex were not independent predictors of mortality.</AbstractText>This meta-analysis identified strong reliable mortality predictors in ICD-HF patients. Age, renal dysfunction, chronic obstructive pulmonary disease, diabetes, peripheral vascular disease, decreased left ventricular ejection fraction, and ICD shocks during follow-up were strong predictors of mortality; ischemic cardiomyopathy and male sex were not. Further research is needed to study other potential predictors, particularly biomarkers.</AbstractText>Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,427 | The risk of adverse events associated with atropine administration during dobutamine stress echocardiography in cardiac transplant patients: a 28-year single-center experience. | Although dobutamine stress echocardiography (DSE) is performed in heart transplant patients, the safety profile of atropine administration in DSE in this setting is unclear.</AbstractText>We identified heart transplant patients who received atropine during DSE from January 1984 to August 2011 at our institution and compared them with a propensity-scored matched control group of heart transplant patients who underwent DSE without atropine. Adverse events were defined as significant arrhythmias (sinus arrest, Mobitz type II heart block, complete heart block, ventricular tachycardia, or ventricular fibrillation), hypotension requiring hospitalization, syncope or presyncope, myocardial infarction, and death. Forty-five heart transplant patients (median age 62 years, 82% male) received 0.2-1 mg atropine during DSE. Of these, 1 patient (2.2%) developed temporary complete heart block. No adverse events were identified in the control group of 154 patients who received dobutamine without atropine.</AbstractText>Our findings suggest that complete heart block can occur infrequently with the administration of atropine in heart transplant patients undergoing DSE. Therefore, patients should be appropriately monitored for these adverse events during and after DSE.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,428 | Polymorphic ventricular tachycardia--part II: the channelopathies. | In this article, we explore the clinical and cellular phenomena of primary electrical diseases of the heart, that is, conditions purely related to ion channel dysfunction and not structural heart disease or reversible acquired causes. This growing classification of conditions, once considered together as "idiopathic ventricular fibrillation," continues to evolve and segregate into diseases that are phenotypically, molecularly, and genetically unique. |
12,429 | Severe hypokalemia probably associated with sertraline use. | To report a case of ventricular fibrillation caused by severe hypokalemia probably associated with sertraline use.</AbstractText>A 48-year-old male patient experienced ventricular fibrillation and cardiac arrest 2 hours after an uneventful coronary angiography procedure, which revealed normal, unobstructed coronary arteries. Blood chemistry was immediately obtained, revealing a very low potassium (K+) level of 2.44 mEq/L. Other blood electrolytes, including magnesium, ECG, and corrected QT intervals, were all within normal limits. A thorough search for an etiology of hypokalemia, including adrenal gland causes, herbal product consumption, and toxic exposure, did not reveal any identifiable cause. This led us to consider the only drug he was on--sertraline 50 mg per day--as the possible culprit.</AbstractText>There has been no clear identification of severe hypokalemia associated with sertraline use in the literature. However, there have been a considerable number of self-reported cases of hypokalemia in patients on sertraline therapy. Scoring according to the Naranjo adverse drug reaction scale revealed a probable relationship between severe hypokalemia and sertraline use in our patient. No clear pathogenic mechanism for the effect of sertraline on serum K equilibrium is known. However, considering the number of self-reported incidences and this case report, the effect of sertraline on serum K levels warrants consideration.</AbstractText>This is the first documented case report of severe hypokalemia probably associated with sertraline use.</AbstractText> |
12,430 | Assessment of adverse events and predictors of neurological recovery after therapeutic hypothermia. | Therapeutic hypothermia improves neurological recovery after witnessed cardiac arrest from ventricular fibrillation or tachycardia. Its application is expanding despite associated adverse events.</AbstractText>To assess the occurrence of adverse events and predictors of good versus poor neurological recovery after therapeutic hypothermia.</AbstractText>A single-center, retrospective review of medical records of 91 patients who received therapeutic hypothermia for ≥6 hours. Adverse events included laboratory abnormalities, shivering, acute kidney injury, or infection. Cerebral performance categories (CPC) scores delineated good (CPC of 1-3) or poor (CPC of 4 or 5) neurological outcomes. Groups were compared and parameters evaluated for effect on neurological recovery using backward logistic regression analysis.</AbstractText>Therapeutic hypothermia was used for several indications, and 42 patients (46.2%) had good neurological recovery. Demographic parameters were similar between groups. Common adverse events were hypoglycemia (98.9%), shivering (84.6%), bradycardia (58.2%), electrolyte abnormalities (26.4%-91.2%), acute kidney injury (52.8%), infection (48.4%), and coagulopathy (40.7%). Characteristics independently associated with neurological recovery included faster return of spontaneous circulation (ROSC), quicker initiation of cooling, and the occurrence of infections. Pulseless electrical activity, faster achievement of goal cooling temperature, seizure, and the administration of insulin or epinephrine were inversely related to neurological recovery.</AbstractText>Adverse events of therapeutic hypothermia were numerous and frequent, necessitating monitoring. Neurological recovery is primarily driven by the type of arrest, the rapidity of ROSC, the time needed to provide and achieve therapeutic hypothermia, the development of seizures or infection, and the use of insulin or epinephrine.</AbstractText> |
12,431 | Incidence of sudden cardiac death after ventricular fibrillation complicating acute myocardial infarction: a 5-year cause-of-death analysis of the FAST-MI 2005 registry. | Limited data are available on long-term prognosis or causes-of-death analysis among survivors of acute myocardial infarction (MI) according to whether or not they developed ventricular fibrillation (VF) during the acute stage of MI.</AbstractText>Among 3670 MI patients hospitalized in France in 2005 and enrolled in this prospective follow-up cohort study, we assessed in-hospital mortality and 5-year cause of death among those who survived to hospital discharge, according to whether they developed VF (116 cases) or not, during the acute stage. 94.5% of patients had complete follow-up at 5 years. In-hospital mortality was significantly higher among VF patients (adjusted OR 7.38, 95% CI 4.27-12.75, P < 0.001). Among 3463 survivors at hospital discharge, 1024 died during a mean follow-up of 52 ± 2 months. The overall survival rate at 5 years was 74.4% (95% CI 72.8-76.0). In Cox multivariate analysis, occurrence of VF during the acute phase of MI was not associated with an increased mortality at 5 years (HR 0.78, 95% CI 0.38-1.58, P = 0.21). The distribution of causes of death at 5 years did not statistically differ according to the presence or absence of VF, especially for sudden cardiac death (13.1% in VF group vs.12.9% in non-VF group), despite a very low rate of implantation of cardioverter defibrillator in both groups (Overall rate 1.2%).</AbstractText>Patients developing VF in the setting of acute MI are at higher risk of in-hospital mortality. However, VF is not associated with a higher long-term all-cause or sudden cardiac death mortality.</AbstractText> |
12,432 | Ibandronate and ventricular arrhythmia risk. | Bisphosphonates, including ibandronate, are used in the prevention and treatment of osteoporosis.</AbstractText>We report a case of suspected ibandronate-associated arrhythmia, following a single dose of ibandronate in a 55-year-old female. ECG at presentation revealed frequent ectopy and QT/QTc interval prolongation; at follow-up 9 months later the QT/QTc intervals were normalized. Proarrhythmic potential of ibandronate was assessed with a combination of in vivo and in vitro approaches in canines and canine ventricular myocytes. We observed late onset in vivo repolarization instability after ibandronate treatment. Myocytes superfused with ibandronate exhibited action potential duration (APD) prolongation and variability, increased early afterdepolarizations (EADs) and reduced Ito (P < 0.05), with no change in IKr . Ibandronate-induced APD changes and EADs were prevented by inhibition of intracellular calcium cycling. Ibandronate increased sarcoplasmic reticulum calcium load; during washout there was an increase in calcium spark frequency and spontaneous calcium waves. Computational modeling was used to examine the observed effects of ibandronate. While reductions in Ito alone had modest effects on APD, when combined with altered RyR inactivation kinetics, the model predicted effects on APD and SR Ca(2+) load consistent with observed experimental results.</AbstractText>Ibandronate may increase the susceptibility to ventricular ectopy and arrhythmias. Collectively these data suggest that reduced Ito combined with abnormal RyR calcium handling may result in a previously unrecognized form of drug-induced proarrhythmia.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,433 | Preventive Effects of the Angiotensin-II Receptor Blocker on Atrial Remodeling in an Ischemic Heart Failure Model of Rats. | It is widely known that angiotensin-II receptor blockers (ARBs) have reverse remodeling effects in atrium. Although atrial fibrillation is frequent in ischemic heart failure clinically, experiments to demonstrate ARB's effects on atrial remodeling in a heart failure model are rare.</AbstractText>A heart failure model and a sham-operated group were formed in 25 Sprague-Dawley male rats of roughly 260 g in weight. Ischemic heart failure models were obtained via ligation of the left anterior descending coronary artery. In the ARB group, 30 mg/kg of losartan was administrated over a day for 4 weeks. Echocardiography was performed to measure left ventricle ejection fraction and left atrial diameter (LAD) at the baseline and 4 weeks after the operation. 4 weeks later, histologic and immunohistochemical evaluation were performed.</AbstractText>Groups were divided into the sham group, heart failure group, and heart failure-ARB group. We maintained 5 rats in each group for 4 weeks after operation. The decrease of left ventricular ejection fraction in the heart failure-ARB group was less than that in the heart failure group (p=0.023). The increase of LAD in the heart failure-ARB group was less than that in the heart failure group (p=0.025). Masson's trichrome stain revealed less fibrosis in the heart failure-ARB group. Immunohistochemical stain and western blot for connexin 43 showed less expression in the heart failure-ARB group.</AbstractText>In the ischemic heart failure model of rats, structurally and histologically, the ARB, losartan, has atrial reverse-remodeling effects. However, electrically, its role as an electrical stabilizer should be studied further.</AbstractText> |
12,434 | Postoperative Atrial Fibrillation following Open Cardiac Surgery: Predisposing Factors and Complications. | New-onset postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery that has substantial effects on outcomes. The aim of this study is to analyze the risk factors in the pre, intra, and postoperative periods, and evaluate its impact on patients' outcome.</AbstractText>In this prospective study, between March 2007 and February 2011, a total of 1254 patients with preoperative sinus rhythm who underwent open cardiac surgery were included of which 177 (13.6%) had developed POAF. Many clinical variables that are associated with the development of POAF, were evaluated.</AbstractText>The study population consisted of 1254 patients that 864 (68.9%) were male and 390 (31.1%) female, and average age was 55.1±15.7 years. POAF occurred in 171 (13.6%) of patients and most of them (68.4%) developed within the first two days after surgery. Multivariate logistic regression analysis was used to identify the following risk factors of POAF: Preoperative risk factors: age>50, smoking, Left ventricular hypertrophy, renal dysfunction, intraoperative risk factors: intraoperative inotrope use, valve surgery, atrial septal defect (ASD) surgery, bicaval cannulation, concomitant cardiac venting of pulmonary and aorta, longer cardiopulmonary time, longer cross-clamp time, postoperative use of inotropic agent after termination of cardiopulmonary bypass.</AbstractText>POAF is the most common arrhythmia after cardiac surgery and not only concerted effort should be performed to identify and to reduce the risk factors, but also effective treatment is necessary to prevent mortality and morbidity.</AbstractText> |
12,435 | Neurological outcomes in patients transported to hospital without a prehospital return of spontaneous circulation after cardiac arrest. | As emergency medical services (EMS) personnel in Japan are not allowed to perform termination of resuscitation in the field, most patients experiencing an out-of-hospital cardiac arrest (OHCA) are transported to hospitals without a prehospital return of spontaneous circulation (ROSC). As the crucial prehospital factors for outcomes are not clear in patients who had an OHCA without a prehospital ROSC, we aimed to determine the prehospital factors associated with 1-month favorable neurological outcomes (Cerebral Performance Category scale 1 or 2 (CPC 1-2)).</AbstractText>We analyzed the data of 398,121 adult OHCA patients without a prehospital ROSC from a prospectively recorded nationwide Utstein-style Japanese database from 2007 to 2010. The primary endpoint was 1-month CPC 1-2.</AbstractText>The rate of 1-month CPC 1-2 was 0.49%. Multivariate logistic regression analysis indicated that the independent variables associated with CPC 1-2 were the following nine prehospital factors: (1) initial non-asystole rhythm (ventricular fibrillation (VF): adjusted odds ratio (aOR), 9.37; 95% confidence interval (CI), 7.71 to 11.4; pulseless ventricular tachycardia (VT): aOR, 8.50; 95% CI, 5.36 to 12.9; pulseless electrical activity (PEA): aOR, 2.75; 95% CI, 2.40 to 3.15), (2) age <65 years (aOR, 3.90; 95% CI, 3.28 to 4.67), (3) arrest witnessed by EMS personnel (aOR, 2.82; 95% CI, 2.48 to 3.19), (4) call-to-hospital arrival time <24 minutes (aOR, 2.58; 95% CI, 2.22 to 3.01), (5) arrest witnessed by any layperson, (6) physician-staffed ambulance, (7) call-to-response time <5 minutes, (8) prehospital shock delivery, and (9) presumed cardiac cause. When four crucial key factors (with an aOR >2.0 in the regression model: initial non-asystole rhythm, age <65 years, EMS-witnessed arrest, and call-to-hospital arrival time <24 minutes) were present, the rates of 1-month CPC 1-2 and 1-month survival were 16.1% and 23.2% in initial VF, 8.3% and 16.7% in pulseless VT, and 3.8% and 9.4% in PEA, respectively.</AbstractText>In OHCA patients transported to hospitals without a prehospital ROSC, nine prehospital factors were significantly associated with 1-month CPC 1-2. Of those, four are crucial key factors: initial non-asystole rhythm, age <65 years, EMS-witnessed arrest, and call-to-hospital arrival time <24 minutes.</AbstractText> |
12,436 | Sudden cardiac arrest in hemodialysis patients with wearable cardioverter defibrillator. | The survival outcome following a sudden cardiac arrest (SCA) in hemodialysis (HD) patients is poor regardless of whether an event takes place in or out of a dialysis center. The characteristics of SCA and post-SCA survival with HD patients using a wearable cardioverter defibrillator (WCD) are unknown.</AbstractText>All HD patients who were prescribed a WCD between 2004 and 2011 and experienced at least one SCA event were included in this study. Demographics, clinical background, characteristics of SCA events were identified from the manufacturer's database. An SCA event was defined as all sustained ventricular tachycardia/fibrillation (VT/VF) or asystole occurring within 24 hours of the index arrhythmia episode. The social security death index was used to determine mortality after WCD use.</AbstractText>A total of 75 HD patients (mean age = 62.9 ± 11.7 years, female = 37.3%) experienced 84 SCA events (119 arrhythmia episodes) while wearing the WCD. Sixty six (78.6%) SCA events were due to VT/VF and 18 (21.4%) were due to asystole. Most SCA episodes occurred between 09:00 and 10:00 (RR = 2.82, 95% CI [1.05, 7.62], P < 0.0001), followed by the 13:00-14:00 time interval (RR = 2.22, 95% CI [0.79, 6.21], P = 0.006). Acute 24-hour survival was 70.7% for all SCA events; 30-day and 1-year survival were 50.7% and 31.4%, respectively. Women had a better post-SCA survival than men (HR = 2.41, 95% CI [1.09, 5.36], P = 0.03).</AbstractText>The use of WCD in HD patients was associated with improved post-SCA survival when compared to historical data.</AbstractText>©2013 ZOLL Medical. Annals of Noninvasive Electrocardiology published by Wiley Periodicals, Inc.</CopyrightInformation> |
12,437 | Acute administration of natural honey protects isolated heart in normothermic ischemia. | This study intended to assess the efficacy of acute administration of natural honey on cardiac arrhythmias and infarct size when it is used during the normothermic ischemia in isolated rat heart. During 30 min of regional normothermic ischemia followed by 120 min of reperfusion, the isolated hearts were perfused by a modified drug free Krebs-Henseleit solution (control) or the solution containing 0.125, 0.25, 0.5 and 1% of freshly prepared natural honey (test groups), respectively. Cardiac arrhythmias were analyzed and determined through the recorded ECGs. The infarct size was measured using computerized planimetry package. At the ischemic phase, honey (0.25 and 0.5%) decreased the number and duration of ventricular tachycardia (VT), total number of ventricular ectopic beats (VEBs), duration and incidence of reversible ventricular fibrillation (VF) and total VF (p < 0.05 for all). During the reperfusion, concentrations of 0.125, 0.25 and 0.5% lowered the number of VT (p < 0.05), duration of reversible VF (p < 0.01) and total number of VEBs (p < 0.05). In addition, VT duration was reduced significantly with honey 0.125 and 0.25%. Moreover, the infarct size was 45.6 ± 3.4% in the control group, while the perfusion of honey (0.125, 0.25 and 0.5%) reduced it to 14.8 ± 5.1 (p < 0.001), 24.6 ± 7.3 (p < 0.01) and 31.4 ± 7.3% (p < 0.05), respectively. Regarding the results, it is concluded that the acute administration of natural honey in normothermic ischemia conditions can protect the rat heart as the reduction of infarct size and arrhythmias. Conceivably, the antioxidant and free radical scavenging activity, the reduction of necrotized tissue and the providence of rich energy source are more important mechanisms in cardioprotective effects of natural honey. |
12,438 | Prolonged Oral Administration of Oleuropein Might Protect Heart against Aconitine-induced Arrhythmia. | In this study, it was surveyed to know whether an oral single dose of oleuropein could mimic the cardiac preconditioning in rats' hearts or whether its prolonged oral administration could protect the heart against the aconitine-induced arrhythmia in rats. Eighty male Wistar rats were divided into two series (n = 8 in each group). In the first series, all groups (except the control (Con) group) were given a single oral dose of oleuropein (20 mg/Kg) 1, 3, 24 and 48 h before the infusion of aconitine. In the second series, except the Con group, the other four groups were given oral oleuropein (20 mg/Kg/day) for 3, 7, 14 and 28 days, before the infusion of aconitine. Electrocardiogram was recorded to monitor arrhythmia. Data of the first series showed that the initiation time of arrhythmia, the initiation of ventricular tachycardia (VT), the numbers of reversible ventricular fibrillation (VF) and the death time had no significant difference compared with Con group. In the second series, a significant protection was occurred only in the 28 days group that was evident with increased initiation time of arrhythmia, increased initiation time of VT, and increased the number of reversible VF and death time in compared to the Con group. The findings of this study show that the oral administration of a single dose of oleuropein could not mimic the preconditioning effects in rat hearts, but the prolonged administration of oleuropein for about four weeks could protect the heart against aconitine-induced arrhythmia. |
12,439 | Therapeutic peritoneal lavage with warm saline solution as an option for a critical hypothermic trauma patient. | In this paper, we present the case of a 63-year-old woman, who was found in her flat lying unconscious on the floor for an unknown time. At the time of admission, her core temperature was 24 °C and ventricular fibrillation was detected on the electrocardiogram (ECG). Because of the unstable conditions, the persistent nonperfusing cardiac rhythm and the dramatically inhibited coagulation cascade, a peritoneal lavage connected to a rapid infuser was performed for rewarming, instead of using a transportable heart-lung machine and a haemodialysis device. After a prolonged cardiopulmonary resuscitation (CPR), the patient could be transferred to the intensive care unit (ICU) in a stable condition. After 40 days in the ICU, recovery was fast, and another month of treatment later, she could be discharged back home without any discomfort.</AbstractText>This report illustrates the successful use of the peritoneal lavage for rewarming a severely hypothermic patient without any extracorporeal rewarming device. Furthermore, it can be used in nearly every hospital if the necessary equipment is affordable. It is demonstrated that this technique is able to provide good outcomes for all victims of accidental hypothermia.</AbstractText> |
12,440 | Prognosis of in-hospital myocardial infarction course for diabetic and nondiabetic patients using a noninvasive evaluation of hemodynamics and heart rate variability. | The objective of our study was to investigate whether the combination of markers of heart rate variability (HRV) and impedance cardiography (ICG) help evaluate the risk of in-hospital death, ventricular arrhythmia, or complicated course secondary to myocardial infarction (STEMI) and to clarify whether combined analysis of HRV and ICG improve prognosis of STEMI, comparing 3 groups: 1) diabetic, 2) nondiabetic, and 3) diabetes-unselected patients.</AbstractText>The parameters reflecting heart rate variability and central hemodynamics were estimated from a 24-hour synchronic electrocardiogram and thoracic impedance signal recordings in 232 patients (67 diabetic) on the third day after myocardial infarction. Logistic regression analysis was used to determine the predictors of selected outcomes. Different prognostic models were compared with the receiver operating characteristic curve analysis.</AbstractText>The model consisting of low- and high-frequency power ratio (LF/HF) and cardiac output (CO) was elaborated for the prognosis of in-hospital death in the group 3 (odds ratios [ORs] were 9.74 and 4.85, respectively). Very low-frequency power (VLF), cardiac index (CIN), and cardiac power output (CPO) were the predictors of ventricular arrhythmia in the group 2 (ORs of 1.005, 5.09, and 66.7, respectively) and the group 3 (ORs of 1.004, 3.84, and 37.04, respectively). The predictors of the complicated in-hospital course in the group 1 were the baseline width of the minimum square difference triangular interpolation of the highest peak of the histogram of all NN intervals (TINN) and stroke volume (SV) (ORs of 1.006, and 1.009, respectively); in the group 2, the mean of the standard deviations of all NN intervals for all 5-minute segments of the recording (SDNN index) and CPO (ORs of 1.06 and 2.44, respectively); and in the group 3, SDNN index, VLF, LF/HF, CIN (ORs of 1.04, 1.004, 2.3, and 3.49, respectively).</AbstractText>The patients with decreased HRV and low estimates of central hemodynamics evaluated by ICG are at an increased risk of the adverse in-hospital course of STEMI. The combined analysis of HRV and ICG hemodynamic estimates contributes to the risk assessment of the complicated in-hospital course of STEMI, in-hospital hemodynamically significant ventricular arrhythmia, and in-hospital death secondary to STEMI. The in-hospital prognostic value of the combined estimates of HRV and ICG is lower in the STEMI patients with diabetes mellitus as compared with the nondiabetic patients.</AbstractText> |
12,441 | Implantable cardioverter-defibrillator therapy before death: high risk for painful shocks at end of life. | Several trials have demonstrated improved survival with implantable cardioverter-defibrillator (ICD) therapy. The cause and nature of death in the ICD population have been insufficiently investigated. The objective of this study was to analyze ICDs from deceased patients to assess the incidence of ventricular tachyarrhythmias, the occurrence of shocks, and possible device malfunction.</AbstractText>We prospectively analyzed intracardiac electrograms in 125 explanted ICDs. The incidence of ventricular tachyarrhythmia, including ventricular fibrillation, and shock treatment was assessed. Ventricular tachyarrhythmia occurred in 35% of the patients in the last hour of their lives; 24% had an arrhythmic storm, and 31% received shock treatment during the last 24 hours. Arrhythmic death was the primary cause of death in 13% of the patients, and the most common cause of death was congestive heart failure (37%). More than half of the patients (52%) had a do-not-resuscitate order, and 65% of them still had the ICD shock therapies activated 24 hours before death. Possible malfunctions of the ICD were found in 3% of all patients.</AbstractText>More than one third of the patients had a ventricular tachyarrhythmia within the last hour of life. Cardiac death was the primary cause and heart failure the specific cause of death in the majority of the cases. Devices remained active in more than half of the patients with a do-not-resuscitate order; almost one fourth of these patients received at least 1 shock in the last 24 hours of life.</AbstractText> |
12,442 | Long-duration ventricular fibrillation exhibits 2 distinct organized states. | Previous studies showed that endocardial activation during long-duration ventricular fibrillation (VF) exhibits organized activity. We identified and quantified the different types of organized activity.</AbstractText>Two 64-electrode basket catheters were inserted, respectively, into the left ventricle and right ventricle of dogs to record endocardial activation from the endocardium during 7 minutes of VF (controls, n=6). The study was repeated with the K(ATP) channel opener pinacidil (n=6) and the calcium channel blocker flunarizine (n=6). After 2 minutes of VF without drugs, 2 highly organized left ventricular endocardial activation patterns were observed: (1) ventricular electric synchrony pattern, in which endocardial activation arose focally and either had a propagation sequence similar to sinus rhythm or arose near papillary muscles, and (2) stable pattern, in which activation was regular and repeatable, sometimes forming a stable re-entrant circuit around the left ventricular apex. Between 3 and 7 minutes of VF, the percent of time ventricular electric synchrony was present was control=25%, flunarizine=24% (P=0.44), and pinacidil=0.1% (P<0.001) and the percent of time stable pattern was present was control=71%, flunarizine=48% (P<0.001), and pinacidil=56% (P<0.001). The remainder of the time, nonstable re-entrant activation with little repeatability was present.</AbstractText>After 3 minutes, VF exhibits 2 highly organized endocardial activation patterns 96% of the time, one potentially arising focally in the Purkinje system that was prevented with a K(ATP) channel opener but not a calcium channel blocker and the other potentially arising from a stable re-entrant circuit near the apical left ventricular endocardium.</AbstractText> |
12,443 | The role of Interleukin-6, its -174 G>C polymorphism and C-reactive protein in idiopathic cardiac arrhythmias in children. | ABSTRACT Purpose: Knowledge about the role of inflammation in the pathogenesis of arrhythmias in children is limited. Several studies have suggested a relationship between plasma IL-6 levels and/or the -174G>C IL-6 gene polymorphism and atrial fibrillation in adults. Our present study was performed to investigate whether serum IL-6, -174G>C IL-6 polymorphism and C-reactive protein (CRP) are associated with arrhythmias of unknown origin in children.</AbstractText>The study included 126 children diagnosed with supraventricular or ventricular arrhythmia. Patients with congenital heart defects as well as arrhythmias of known origin were excluded from the study. The control group comprised 37 healthy children. The 24 hour Holter electrocardiography monitoring was performed. Serum IL-6, -174 GC IL-6 polymorphism and CRP concentrations were measured on admission.</AbstractText>There were no differences in IL-6, CRP and -174 G>C IL-6 genotype distribution between the control and patient groups. No significant differences in IL-6, CRP and -174 G>C IL-6 genotypes were observed between children with supraventricular or ventricular arrhythmias. The severity of arrhythmias showed also no associations with IL-6, CRP or -174 G>C IL-6 genotypes.</AbstractText>The results suggest that idiopathic cardiac arrhythmias of unknown origin in children are not associated with selected pro-inflammatory markers of infections i.e. elevated IL-6, CRP or -174 G>C IL-6 polymorphism. This new information can effectively reduce the total financial cost of unnecessary diagnosis and treatment of children affected by cardiac arrhythmias.</AbstractText> |
12,444 | Ventricular pacing on the prognosis of patients with pacemaker implantation. | Excessive right ventricular apex pacing has significant adverse effects on the cardiac function and hence, it is necessary to clinically optimize pacing parameters and advocate suitable physiological pacing to safeguard the cardiac function after pacemaker implant. Minimizing ventricular pacing is an atrioventricular node priority function, to encourage ventricular self conduction and to reduce unnecessary right ventricular pacing. Minimized ventricular pacing reduces ventricular pacing by encouraging self atrioventricular conduction function and extending the AV interval. This study is a prospective cohort study to evaluate the changes of cardiac function in patients and serum amino-terminal natriuretic peptide (NT-proBNP) before and after pacing, and the risk of atrial fibrillation with different CUM% VP. The study has shown that the cardiac function will deteriorate with an increase in pacing rate. |
12,445 | Effect of prehospital induction of mild hypothermia on survival and neurological status among adults with cardiac arrest: a randomized clinical trial. | Hospital cooling improves outcome after cardiac arrest, but prehospital cooling immediately after return of spontaneous circulation may result in better outcomes.</AbstractText>To determine whether prehospital cooling improves outcomes after resuscitation from cardiac arrest in patients with ventricular fibrillation (VF) and without VF.</AbstractText><AbstractText Label="DESIGN, SETTING, AND PARTICIPANTS" NlmCategory="METHODS">A randomized clinical trial that assigned adults with prehospital cardiac arrest to standard care with or without prehospital cooling, accomplished by infusing up to 2 L of 4°C normal saline as soon as possible following return of spontaneous circulation. Adults in King County, Washington, with prehospital cardiac arrest and resuscitated by paramedics were eligible and 1359 patients (583 with VF and 776 without VF) were randomized between December 15, 2007, and December 7, 2012. Patient follow-up was completed by May 1, 2013. Nearly all of the patients resuscitated from VF and admitted to the hospital received hospital cooling regardless of their randomization.</AbstractText>The primary outcomes were survival to hospital discharge and neurological status at discharge.</AbstractText>The intervention decreased mean core temperature by 1.20°C (95% CI, -1.33°C to -1.07°C) in patients with VF and by 1.30°C (95% CI, -1.40°C to -1.20°C) in patients without VF by hospital arrival and reduced the time to achieve a temperature of less than 34°C by about 1 hour compared with the control group. However, survival to hospital discharge was similar among the intervention and control groups among patients with VF (62.7% [95% CI, 57.0%-68.0%] vs 64.3% [95% CI, 58.6%-69.5%], respectively; P = .69) and among patients without VF (19.2% [95% CI, 15.6%-23.4%] vs 16.3% [95% CI, 12.9%-20.4%], respectively; P = .30). The intervention was also not associated with improved neurological status of full recovery or mild impairment at discharge for either patients with VF (57.5% [95% CI, 51.8%-63.1%] of cases had full recovery or mild impairment vs 61.9% [95% CI, 56.2%-67.2%] of controls; P = .69) or those without VF (14.4% [95% CI, 11.3%-18.2%] of cases vs 13.4% [95% CI,10.4%-17.2%] of controls; P = .30). Overall, the intervention group experienced rearrest in the field more than the control group (26% [95% CI, 22%-29%] vs 21% [95% CI, 18%-24%], respectively; P = .008), as well as increased diuretic use and pulmonary edema on first chest x-ray, which resolved within 24 hours after admission.</AbstractText>Although use of prehospital cooling reduced core temperature by hospital arrival and reduced the time to reach a temperature of 34°C, it did not improve survival or neurological status among patients resuscitated from prehospital VF or those without VF.</AbstractText>clinicaltrials.gov Identifier: NCT00391469.</AbstractText> |
12,446 | Detection of life-threatening arrhythmias using feature selection and support vector machines. | Early detection of ventricular fibrillation (VF) and rapid ventricular tachycardia (VT) is crucial for the success of the defibrillation therapy. A wide variety of detection algorithms have been proposed based on temporal, spectral, or complexity parameters extracted from the ECG. However, these algorithms are mostly constructed by considering each parameter individually. In this study, we present a novel life-threatening arrhythmias detection algorithm that combines a number of previously proposed ECG parameters by using support vector machines classifiers. A total of 13 parameters were computed accounting for temporal (morphological), spectral, and complexity features of the ECG signal. A filter-type feature selection (FS) procedure was proposed to analyze the relevance of the computed parameters and how they affect the detection performance. The proposed methodology was evaluated in two different binary detection scenarios: shockable (FV plus VT) versus nonshockable arrhythmias, and VF versus nonVF rhythms, using the information contained in the medical imaging technology database, the Creighton University ventricular tachycardia database, and the ventricular arrhythmia database. sensitivity (SE) and specificity (SP) analysis on the out of sample test data showed values of SE=95%, SP=99%, and SE=92% , SP=97% in the case of shockable and VF scenarios, respectively. Our algorithm was benchmarked against individual detection schemes, significantly improving their performance. Our results demonstrate that the combination of ECG parameters using statistical learning algorithms improves the efficiency for the detection of life-threatening arrhythmias. |
12,447 | Evolution of clinical diagnosis in patients presenting with unexplained cardiac arrest or syncope due to polymorphic ventricular tachycardia. | A systematic evaluation of patients with unexplained cardiac arrest (UCA) yields a diagnosis in 50% of the cases. However, evolution of clinical phenotype, identification of new disease-causing mutations, and description of new syndromes may revise the diagnosis.</AbstractText>To assess the evolution in diagnosis among patients with initially UCA.</AbstractText>Diagnoses were reviewed for all patients with UCA recruited from the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry with at least 1 year of follow-up.</AbstractText>After comprehensive investigation of 68 patients (age 45.2 ± 14.9 years; 63% men), the initial diagnosis was as follows: idiopathic ventricular fibrillation (n = 34 [50%]), a primary arrhythmic disorder (n = 21 [31%]), and an occult structural cause (n = 13 [19%]). Patients were followed for 30 ± 17 months, during which time the diagnosis changed in 12 (18%) patients. A specific diagnosis emerged for 7 patients (21%) with an initial diagnosis of idiopathic ventricular fibrillation. A structural cardiomyopathy evolved in 2 patients with an initial diagnosis of primary electrical disorder, while the specific structural cardiomyopathy was revised for 1 patient. Two patients with an initial diagnosis of a primary arrhythmic disorder were subsequently considered to have a different primary arrhythmic disorder. A follow-up resting electrocardiogram was the test that most frequently changed the diagnosis (67% of the cases), followed by genetic testing (17%).</AbstractText>The reevaluation of patients presenting with UCA may lead to a change in diagnosis in up to 20%. This emphasizes the need to actively monitor the phenotype and also has implications for the treatment of these patients and the screening of their relatives.</AbstractText>© 2014 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.</CopyrightInformation> |
12,448 | Phased RF ablation in persistent atrial fibrillation. | Persistent and long-standing persistent atrial fibrillation (AF) often requires extensive and/or repeat radiofrequency (RF) ablation procedures.</AbstractText>The Tailored Treatment of Persistent Atrial Fibrillation (TTOP-AF) study assessed the effectiveness and safety of the phased RF system in a randomized controlled comparison of medical therapy against phased RF ablation for the management of persistent and long-standing persistent AF.</AbstractText>Patients who had failed at least 1 antiarrhythmic drug (AAD) were randomized (2:1) to ablation management (AM) or medical management (MM). AM patients were allowed up to 2 ablations. Index and retreatment procedures consisted of pulmonary vein isolation and ablation of complex fractionated atrial electrograms. MM patients received AAD changes and/or cardioversion. The primary end points of the TTOP-AF study included chronic effectiveness and safety at 6 months and acute safety within 7 days of ablation.</AbstractText>At 6 months, a greater proportion of AM patients achieved effectiveness off AAD (77 of 138 [55.8%]) compared to MM patients (19 of 72 [26.4%]) (P < .0001). Acutely, 92.8% (128/138) of the procedures were successful while 12.3% (17/138) experienced a serious procedure and/or device-related adverse event. The predefined acute safety end point was not met. The proportion of patients with chronic safety events did not differ significantly between groups.</AbstractText>Catheter ablation of persistent/long-standing persistent AF with the phased RF ablation system is effective with greater reduction of AF compared with MM. More intense anticoagulation strategies, careful attention to catheter placement relative to the pulmonary vein ostia, and elimination of electrode interaction are expected to reduce the risk of stroke, pulmonary vein stenosis, and asymptomatic cerebral emboli.</AbstractText>© 2014 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.</CopyrightInformation> |
12,449 | Addition of glucagon to adrenaline improves hemodynamics in a porcine model of prolonged ventricular fibrillation. | Cardiac arrest is a daunting medical emergency. The aim of the present study was to assess whether the combination of adrenaline and glucagon would improve initial resuscitation success, 48-hour survival, and neurologic outcome compared with adrenaline alone in a porcine model of ventricular fibrillation.</AbstractText>Ventricular fibrillation was induced in 20 healthy Landrace/Large White piglets, which were subsequently left untreated for 8 minutes. The animals were randomized to receive adrenaline alone (n = 10, group C) and adrenaline plus glucagon (n = 10, group G). All animals were resuscitated according to the 2010 European Resuscitation Council guidelines. Hemodynamic variables were measured before arrest, during arrest and resuscitation, and during the first 60 minutes after return of spontaneous circulation. Survival and a neurologic alertness score were measured at 48 hours after return of spontaneous circulation.</AbstractText>Return of spontaneous circulation was achieved in 8 animals (80%) from group C and 10 animals (100%) from group G (P = .198). A significant gradual increase in coronary perfusion pressure and diastolic aortic pressure over time, which started 1 minute after the onset of cardiopulmonary resuscitation, was observed. Three animals (30%) from group C and 9 animals (90%) from group G survived after 48 hours (P = .006), whereas neurologic examination was significantly better in the animals of group G (P < .001).</AbstractText>In this porcine model of prolonged ventricular fibrillation, the addition of glucagon to adrenaline improves hemodynamics during resuscitation and early postresuscitation period and may increase survival.</AbstractText>© 2013.</CopyrightInformation> |
12,450 | Dantrolene suppresses ventricular ectopy and arrhythmogenicity with acute myocardial infarction in a langendorff-perfused pacing-induced heart failure rabbit model. | Dantrolene prevents arrhythmogenic Ca(2+) release during heart failure (HF). However, direct evidence to support its antiarrhythmic effects in failing hearts with acute myocardial infarction (AMI) is lacking.</AbstractText>HF was induced by right ventricular pacing (312 beats/min, 4 weeks) in 19 rabbits. AMI was induced by coronary artery ligation in rabbits surviving chronic pacing (n = 17). The hearts were quickly excised and Langendorff-perfused for simultaneous membrane potential and intracellular Ca(2+) (Cai ) optical mapping when ventricular fibrillation (VF) occurred or 4 hours after AMI. The VF inducibility was defined as the ability to provoke sustained VF (>2 minutes) by pacing. Dantrolene (10 μM) was administered after baseline studies. Spontaneous VF occurred in 5 rabbits (SVF group). The ventricular premature beat (VPB) burden was significantly higher in the SVF group than the non-SVF group (P < 0.05). Dantrolene suppressed VPB burden (P = 0.03) and prolonged action potential duration (APD; P < 0.05) to reduce VF inducibility (P < 0.05). However, dantrolene shortened immediate postshock APD50 even if VF storm was suppressed.</AbstractText>In failing hearts with AMI, VPB burden plays a pivotal role in SVF occurrence. Dantrolene suppresses VPBs and/or prolongs repolarization to inhibit spontaneous VF and reduce VF inducibility.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,451 | Low mortality and low rate of perceived and documented arrhythmias after Cox maze III surgery for atrial fibrillation. | To report a long-term single-site experience of the cut-and-sew Cox maze III procedure for atrial fibrillation (AF).</AbstractText>A total of 232 consecutive patients underwent the Cox maze III procedure for symptomatic therapy-refractory AF, with concomitant surgery in 34 patients. Follow-up data were obtained from electrocardiograms, patient visits, questionnaires, and medical files.</AbstractText>There were 103 patients (44%) with paroxysmal AF during 8.8 ± 6.5 years and 129 patients (56%) with nonparoxysmal AF for 7.3 ± 6.7 years. The preoperative New York Heart Association class was better in patients with paroxysmal AF (P < 0.0001); the left ventricular ejection fraction was 59 ± 7% versus 56 ± 8%, P = 0.003, and the left atrial area 24 ± 6 versus 27 ± 6 cm(2) , P = 0.01. Early and late postoperative adverse events occurred at similar rates. Four patients from each group died of reasons unrelated to surgery. The mean follow-up was 66 ± 42 (5-155) months. In total, 184/229 (80%) patients were free of documented AF/atrial flutter/atrial tachycardia (AF/AFl/AT) off antiarrhythmic drugs (AA) and 189/229 (83%) on or off AA. The hazard ratio (HR) for paroxysmal versus nonparoxysmal AF patients regarding documented AF/AFl/AT was 0.8 (95% confidence interval [CI] 0.4-1.4; P = 0.40). For patients without versus with concomitant surgery, the corresponding HR was 0.4 (95% CI 0.2-0.8; P = 0.008). Of 197 patients (89%) responding to the questionnaire, 41 had sought care for symptoms of arrhythmia, 29 of whom had documented AF/AFl/AT, whereas another six had other arrhythmias.</AbstractText>Cut-and-sew Cox maze III surgery provided long-lasting high efficacy, also in patients with nonparoxysmal AF of long duration and/or concomitant surgery, and was associated with low rates of subsequent adverse events.</AbstractText>©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,452 | Evaluation of time course and predicting factors of progression of paroxysmal or persistent atrial fibrillation to permanent atrial fibrillation. | To evaluate time course and predictors of progression of paroxysmal or persistent atrial fibrillation (AF) to permanent AF.</AbstractText>We included 460 patients referred for paroxysmal (n = 337) or persistent (n = 123) AF between 1994 and 2012. Mean follow-up was 13.2 ± 6.5 years. AF progression rate was 3.7% per year, 19.7% at 5 years, and 38.1% at 10 years. Lone AF was diagnosed in 217 patients (47%). Predictors of permanent AF were: age, persistent AF, left atrial (LA) size, left ventricular-fractional shortening (LV-FS), lack of antiarrhythmic (AA) drugs, VVI pacing (P < 0.001 for all), and valvular disease (P < 0.02). Independent predictors were age (P < 0.001), persistent AF (P < 0.001), LA diameter (P < 0.005), lack of AA drugs (P < 0.005), and VVI pacing (P < 0.01). When adjusted at means of covariates, persistent AF and age >75 years remained highly significant (P < 0.01). LA dimension >50 mm was highly significant at univariate model (P < 0.001) but to a lesser extent when adjusted (P < 0.05). In patients with paroxysmal AF-with age <75 years-on AA drugs, progression rate to permanent AF was 6.5% at 5 years and 23.7% at 10 years. Among four predictors (age, LA size, LV-FS, and VVI pacing), only age (P < 0.01) and LA size (P < 0.005) remained independently significant, but LA size was not significant when adjusted.</AbstractText>Progression to permanent AF is a slow process. Aging, LA size, VVI pacing, lack of AA therapy, and a persistent form of AF independently increased the progression to permanent AF.</AbstractText>©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,453 | Comparative evaluation of methodologies for T-wave alternans mapping in electrograms. | Electrograms (EGM) recorded from the surface of the myocardium are becoming more and more accessible. T-wave alternans (TWA) is associated with increased vulnerability to ventricular tachycardia/fibrillation and it occurs before the onset of ventricular arrhythmias. Thus, accurate methodologies for time-varying alternans estimation/detection in EGM are needed. In this paper, we perform a simulation study based on epicardial EGM recorded in vivo in humans to compare the accuracy of four methodologies: the spectral method (SM), modified moving average method, laplacian likelihood ratio method (LLR), and a novel method based on time-frequency distributions. A variety of effects are considered, which include the presence of wide band noise, respiration, and impulse artifacts. We found that 1) EGM-TWA can be detected accurately when the standard deviation of wide-band noise is equal or smaller than ten times the magnitude of EGM-TWA. 2) Respiration can be critical for EGM-TWA analysis, even at typical respiratory rates. 3) Impulse noise strongly reduces the accuracy of all methods, except LLR. 4) If depolarization time is used as a fiducial point, the localization of the T-wave is not critical for the accuracy of EGM-TWA detection. 5) According to this study, all methodologies provided accurate EGM-TWA detection/quantification in ideal conditions, while LLR was the most robust, providing better detection-rates in noisy conditions. Application on epicardial mapping of the in vivo human heart shows that EGM-TWA has heterogeneous spatio-temporal distribution. |
12,454 | Conductive channels identified with contrast-enhanced MR imaging predict ventricular tachycardia in systolic heart failure. | This study evaluated whether the conductive channel (CC) identified by late gadolinium enhanced-cardiac magnetic resonance (LGE-CMR) is associated with ventricular tachycardia (VT) in patients with systolic heart failure (HF).</AbstractText>One recent study demonstrated that the CC formed by heterogeneous tissue within the core scar could be detected by LGE-CMR and that the CC is responsible for clinical VT. We hypothesized that the CC could help identify HF patients at risk for VT.</AbstractText>A total of 63 patients from a CMR database with left ventricular ejection fraction (LVEF) below 50% and with hyperenhancement on LGE-CMR were included. The cine and LGE images were analyzed to derive the LV function and scar characteristics, and to identify the CC. The outcomes, including VT, ventricular fibrillation (VF), and total mortality, were obtained by reviewing medical records.</AbstractText>After a median 1,379 (interquartile range: 271 to 1,896) days of follow-up, 8 patients had VT/VF attacks and 14 patients died. Among the CMR-measured parameters, only the probability of identifying the CC by LGE-CMR was higher in patients with VT/VF than those without VT/VF (75.0% vs. 16.4%, p < 0.001). The probability of identifying the CC was also higher in the total mortality group than the survival group (50.0% vs. 16.3%, p = 0.004). The other LGE-CMR variables were not significantly different between the 2 groups. A univariate Cox regression model showed that CC identification was positively associated with VT/VF attacks (hazard ratio [HR]: 27.032, 95% confidence interval [CI]: 3.291 to 222.054, p = 0.002) and excess total mortality (HR: 4.766, 95% CI: 1.643 to 13.824, p = 0.004). The LVEF was inversely associated with VT/VF attacks (HR: 0.119, 95% CI: 0.015 to 0.977, p = 0.048) and excess total mortality (HR: 0.491, 95% CI: 0.261 to 0.925, p = 0.028) during follow-up.</AbstractText>We demonstrated that CC identification using LGE-CMR can help identify HF patients at risk for VT/VF.</AbstractText>Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,455 | [Effects of cardiac resynchronization therapy in patients with advanced congestive heart failure evaluated by real-time 3-dimensional echocardiography]. | To quantitatively assess the effects of cardiac resynchronization therapy (CRT) in patients with advanced congestive heart failure by real-time 3-dimensional(3D) echocardiography (RT-3DE).</AbstractText>Eighteen patients with advanced congestive heart failure underwent CRT with New York Heart association(NYHA) class III and IV and wide QRS complex (>120 ms) were included (17 dilated cardiomyopathy and 1 ischemic cardiomyopathy). Before CRT and 8 months after CRT, the clinical and RT-3DE parameters and outcome were analyzed.</AbstractText>The biventricular pacemaker was successfully implanted in 17 patients (94.4%). Compared with before CRT, NYHA class of patients decreased by 1.5 class (P < 0.01), left ventricular ejection fraction increased by 25% (P < 0.01), left ventricular end systolic volume decreased by 38% (P < 0.01), left ventricular systolic dyssynchrony index (SDI) improved significantly (14.2% before CRT vs. 9.8% after CRT, P < 0.01 ) post CRT. Change in SDI and change in LVEF was positively correlated (r = 0.62, P < 0.01) . The procedure complications and outcome during and after CRT included coronary sinus dissection (n = 1), left ventricular lead dislodgement (n = 1), phrenic nerve stimulation (n = 1), sudden cardiac death (n = 1). Three non-response patients were complicated with atrial fibrillation, nonspecific intraventricular block and dilated cardiomyopathy with postero-lateral scar tissue.</AbstractText>CRT could improve the cardiac function, correct the mechanical desynchronization and reverse left ventricular remodeling in patients with congestive heart failure, and SDI quantification by RT-3DE could predict increase of LVEF after CRT, however, there were complications related to the implantation procedure and possibilities of non-response.</AbstractText> |
12,456 | Congenital and hereditary causes of sudden cardiac death in young adults: diagnosis, differential diagnosis, and risk stratification. | Sudden cardiac death is defined as death from unexpected circulatory arrest-usually a result of cardiac arrhythmia-that occurs within 1 hour of the onset of symptoms. Proper and timely identification of individuals at risk for sudden cardiac death and the diagnosis of its predisposing conditions are vital. A careful history and physical examination, in addition to electrocardiography and cardiac imaging, are essential to identify conditions associated with sudden cardiac death. Among young adults (18-35 years), sudden cardiac death most commonly results from a previously undiagnosed congenital or hereditary condition, such as coronary artery anomalies and inherited cardiomyopathies (eg, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy [ARVC], dilated cardiomyopathy, and noncompaction cardiomyopathy). Overall, the most common causes of sudden cardiac death in young adults are, in descending order of frequency, hypertrophic cardiomyopathy, coronary artery anomalies with an interarterial or intramural course, and ARVC. Often, sudden cardiac death is precipitated by ventricular tachycardia or fibrillation and may be prevented with an implantable cardioverter defibrillator (ICD). Risk stratification to determine the need for an ICD is challenging and involves imaging, particularly echocardiography and cardiac magnetic resonance (MR) imaging. Coronary artery anomalies, a diverse group of congenital disorders with a variable manifestation, may be depicted at coronary computed tomographic angiography or MR angiography. A thorough understanding of clinical risk stratification, imaging features, and complementary diagnostic tools for the evaluation of cardiac disorders that may lead to sudden cardiac death is essential to effectively use imaging to guide diagnosis and therapy. |
12,457 | Untreated preoperative depression is not associated with postoperative arrhythmias in CABG patients. | The mechanism by which depression affects postoperative outcome may involve arrhythmias. The purpose of this study was to evaluate whether untreated depression is associated with an increased incidence of postoperative arrhythmias in patients undergoing coronary artery bypass graft surgery (CABG).</AbstractText>One hundred seven patients were assessed for signs of depression with the Prime-MD Patient Health Questionnaire (brief PHQ) one week before surgery and subsequently underwent Holter monitoring for 48-72 hr postoperatively. The incidences of atrial fibrillation (AF); supraventricular tachycardia (SVT); ventricular tachycardia (VT), defined as three or more consecutive beats at a cycle length less than 600 msec; ventricular fibrillation (VF); and average heart rate (HR) were recorded in patients with and without signs of depression.</AbstractText>The incidence of preoperative untreated depression was 27% (29/107). Twenty patients had mild depression (brief PHQ score of 5-9), seven patients had moderate depression (a score of 10-14), and two patients had severe depression (a score of 20). The incidences of postoperative AF, SVT, and non-sustained VT in depressed and non-depressed patients were 37.9% vs 35.9%, respectively (P = 0.50), 34.4% vs 52.5%, respectively (P = 0.07), and 17.2% vs 37.1%, respectively (P = 0.04). The average (SD) postoperative HR was similar in both groups [95 (12) beats·min(-1) in depressed patients and 92 (10) beats·min(-1) in non-depressed patients, (P = 0.25)]. Multivariate regression analysis showed that older age, but not depression, was a risk factor for postoperative arrhythmia.</AbstractText>Preoperative untreated depression is not related to postoperative arrhythmia in the early postoperative period in patients undergoing elective CABG. This trial was registered at clinicaltrials.gov (number: NCT00622024).</AbstractText> |
12,458 | A less aggressive therapeutic option for electrical storm. | Electrical storm (ES) describes the rapidly clustering ventricular fibrillation (VF) that requires multiple cardioversions. Emerging evidence suggests that Purkinje arborization and sympathetic nerve regeneration play a major role in initiating malignant arrhythmias. We report the case of two patients who, after having survived an acute myocardial infarction (MI), developed repetitive episodes of polymorphic ventricular tachycardia and VF one week after percutaneous revascularization, triggered by monomorphic premature ventricular contractions (PVCs). Owing to repetitive and drug-refractory VF episodes, temporary atrial overdrive pacing was attempted with complete suppression of VF. In the following month, recurrence of ventricular arrhythmia was inversely related to the atrial pacing rate. Although antiarrhythmic drugs other than beta-blockers had been discontinued, neither PVCs nor ventricular arrhythmias recurred at one-month follow-up when the lower pacing rate was set at 60 bpm. In conclusion in these patients, ES was likely related to nerve sprouting after ischemic injury. This chaotic phenomenon occurs early after tissue damage and shows a peak seven days after acute MI with degeneration of superfluous axon branches. High pacing rates can reduce early after depolarizations and suppress PVCs, thus preventing ES. On these grounds, ES patients may be treated with temporary overdrive pacing rather than early radiofrequency ablation. |
12,459 | Evaluating the impact of implementing an early warning score system on incidence of in-hospital cardiac arrest. | To evaluate the introduction of an early warning score (EWS) system on incidence of in-hospital adult cardiac arrest.</AbstractText>A before-after evaluation of an EWS system (in the form of a patient observation chart with escalation protocol) in a 600 bed tertiary teaching hospital in New Zealand during the two 12-month periods between March 2009 and March 2011. Difference in incidence rates was compared using Student's t test.</AbstractText>There were 168 cardiac arrests during the 24 month period. The incidence rate of cardiac arrests per 1000 admissions was 4.67 during 2009-2010 and 2.91 during 2010-2011 (mean difference of 1.77, 95%CI 0.59-2.94). The number of cardiac arrests dropped from an average of 8.5 arrests per month during 2009-2010 to 5.5 arrests per month during 2010-2011 following the introduction of ADDS (mean difference 3.0, 95%CI 0.78-5.22). There was no significant increase in the number of medical emergency calls (7.5 calls versus 9.1 calls per month).</AbstractText>Introduction of an EWS system in addition to an existing cardiac arrest team response decreased the incidence of in-hospital cardiac arrests in a tertiary hospital in New Zealand.</AbstractText> |
12,460 | [Current treatment of tachycardia]. | Tachycardias including atrial fibrillation often require hospitalisation. A diagnostic algorithm from the surface ECG allows discrimination between supraventricular and ventricular tachycardias. For acute treatment, only a few antiarrhythmic drugs such as adenosine, ajmaline and amiodarone, and in case of hemodynamic instability electrocardioversion are required. For long-term treatment catheter ablation is the option of choice for almost all patients with supraventricular tachycardias, atrial flutter, idiopathic ventricular tachycardias and for many patients with symptomatic atrial fibrillation. Chronic antiarrhythmic drug therapy is less often used. In patients with ventricular tachyarrhythmias in the setting of severe structural heart disease, risk stratification must be performed and ICD therapy is often indicated. Anticoagulant therapy according to risk score analysis is often indicated in patients with atrial fibrillation. |
12,461 | Is atrial fibrillation always a culprit of stroke in patients with atrial fibrillation plus stroke? | Some ischemic strokes in patients with atrial fibrillation (AF) are caused by noncardioembolic etiologies (AF-unrelated stroke), but not AF itself (AF-related stroke). However, most clinical trials on the risk of stroke in AF have not distinguished between these. We investigated the frequency and features of AF-unrelated versus AF-related strokes in patients with AF plus ischemic stroke. We hypothesized that certain clinical factors, including chronicity of AF, treatment at the time of stroke onset and echocardiographic findings, may help to discriminate between AF-related and AF-unrelated strokes. The mechanisms and antithrombotic medications at the time of stroke recurrence in the two groups were also examined.</AbstractText>Consecutive patients with ischemic stroke within 7 days of symptom onset and with AF were included. Patients were classified according to the previously published criteria. Clinical factors including CHADS2 and CHA2DS2-VASc scores and transthoracic echocardiographic (TTE) findings were evaluated.</AbstractText>Of 522 patients, 424 (81.2%) were grouped as AF-related stroke and the remaining 90 (17.2%) were classified as AF-unrelated stroke. Among the patients with AF-unrelated stroke, 51 (9.8%) were categorized as possible large artery atherosclerosis and 38 (7.3%) as possible small artery occlusion; 1 patient (0.2%) was assigned to miscellaneous cause. The AF-related and AF-unrelated strokes had similar CHADS2 and CHA2DS2-VASc scores. However, compared to AF-unrelated stroke, AF-related stroke was independently associated with female sex (odds ratio, OR, 2.19; 95% confidence interval, CI, 1.18-4.05), sustained AF (OR, 2.09; 95% CI, 1.21-3.59), inadequate anticoagulation at stroke onset (OR, 3.21; 95% CI, 1.33-7.75) and left ventricular dysfunction on TTE (OR, 2.84; 95% CI, 1.40-5.74). We identified 26 patients who experienced 2 strokes during the study period. The initial stroke subtype was a strong predictor of the recurrent stroke mechanism (p < 0.001). Among 17 events of AF-related recurrent stroke in these subpopulation, only 2 strokes (11.8%) occurred in a setting of adequate anticoagulation, whereas 4 out of 9 patients (44.4%) who had AF-unrelated strokes at recurrence were sufficiently anticoagulated at the time of admission (p = 0.138).</AbstractText>AF is not always a culprit of stroke in patients with AF plus ischemic stroke; approximately one sixth of these cases are unrelated to AF and have distinct characteristics compared to AF-related stroke. There are significant differences in terms of some clinical and TTE parameters between AF-related and AF-unrelated stroke. Future studies are warranted to optimize strategies for risk stratification, treatment and prevention of stroke in these patients.</AbstractText> |
12,462 | Calsequestrin 2 deletion causes sinoatrial node dysfunction and atrial arrhythmias associated with altered sarcoplasmic reticulum calcium cycling and degenerative fibrosis within the mouse atrial pacemaker complex1. | Loss-of-function mutations in Calsequestrin 2 (CASQ2) are associated with catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT patients also exhibit bradycardia and atrial arrhythmias for which the underlying mechanism remains unknown. We aimed to study the sinoatrial node (SAN) dysfunction due to loss of CASQ2.</AbstractText>In vivo electrocardiogram (ECG) monitoring, in vitro high-resolution optical mapping, confocal imaging of intracellular Ca(2+) cycling, and 3D atrial immunohistology were performed in wild-type (WT) and Casq2 null (Casq2(-/-)) mice. Casq2(-/-) mice exhibited bradycardia, SAN conduction abnormalities, and beat-to-beat heart rate variability due to enhanced atrial ectopic activity both at baseline and with autonomic stimulation. Loss of CASQ2 increased fibrosis within the pacemaker complex, depressed primary SAN activity, and conduction, but enhanced atrial ectopic activity and atrial fibrillation (AF) associated with macro- and micro-reentry during autonomic stimulation. In SAN myocytes, CASQ2 deficiency induced perturbations in intracellular Ca(2+) cycling, including abnormal Ca(2+) release, periods of significantly elevated diastolic Ca(2+) levels leading to pauses and unstable pacemaker rate. Importantly, Ca(2+) cycling dysfunction occurred not only at the SAN cellular level but was also globally manifested as an increased delay between action potential (AP) and Ca(2+) transient upstrokes throughout the atrial pacemaker complex.</AbstractText>Loss of CASQ2 causes abnormal sarcoplasmic reticulum Ca(2+) release and selective interstitial fibrosis in the atrial pacemaker complex, which disrupt SAN pacemaking but enhance latent pacemaker activity, create conduction abnormalities and increase susceptibility to AF. These functional and extensive structural alterations could contribute to SAN dysfunction as well as AF in CPVT patients.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2013. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
12,463 | Hypokalemia mimicking a herniated vertebral disc. | A herniated vertebral disc is a common cause of paralysis. Other causes include infections, tumors, and neurologic diseases. A rare and dangerous but in most cases easily treatable cause is hypokalemia. Clinically, the acute symptoms may resemble a herniated vertebral disc, but hypokalemia per se is life-threatening by causing heart arrest through ventricular tachycardia or fibrillation.</AbstractText>A patient with back pain and neurologic deficit in the lower extremities after a history of a herniated vertebral disc presented, who finally receives the diagnosis of hypokalemia.</AbstractText>Case report.</AbstractText>A 25-year-old female patient presenting after a fall with muscle weakness in both legs was followed clinically and radiographically.</AbstractText>Neurological examination showed a lower extremity muscle weakness with three-fifths muscular strength of the quadriceps and tibialis anterior muscle on both sides. Reflexes were diminished bilaterally, anal sphincter tone was normal. Plain radiography suggested a posterior rim fracture of L5, but computed tomography did not confirm this diagnosis. The laboratory investigation revealed a hypokalemia of 1.7 mEq/L. On electrolyte replacement, the patient recovered immediately.</AbstractText>This report describes a misleading diagnostic case of back pain and neurologic deficit after a trauma and sensitizes for the possible life-threatening diagnosis hypokalemia, which is rare but easily treatable.</AbstractText>Copyright © 2015 Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,464 | QT Variability Index. | The QT Variability Index (QTVI) is a non-invasive measure of repolarization lability that has been applied to a wide variety of subjects with cardiovascular disease. It is a ratio of normalized QT variability to normalized heart rate variability, and therefore includes an assessment of autonomic nervous system tone. The approach assesses beat-to-beat variability in the duration of the QT and U wave in conventional surface electrocardiographic recordings, as well as determines the heart rate variability (HRV) from the same recording. As opposed to T wave alternans, QTVI assesses variance in repolarization at all frequencies. Nineteen studies have published data on QTVI in healthy individuals, while 20 have evaluated its performance in cohorts with cardiovascular disease. Six studies have assessed the utility of QTVI in predicting VT/VF, cardiac arrest, or cardiovascular death. A prospective study utilizing QTVI to determine therapy allocation has not been performed, and therefore the final determination of the value of the metric awaits definitive exploration. |
12,465 | Ambulatory ECG-based T-wave alternans monitoring for risk assessment and guiding medical therapy: mechanisms and clinical applications. | Identification of individuals at risk for sudden cardiac death (SCD), the main cause of adult mortality in developed countries, remains a major challenge. The main contemporary noninvasive marker, left ventricular ejection fraction (LVEF), has not proved adequately reliable, as the majority of individuals who die suddenly have relatively preserved cardiac mechanical function. Monitoring of T-wave alternans (TWA), a beat-to-beat fluctuation in ST-segment or T-wave morphology, on ambulatory electrocardiogram (AECG) is an attractive approach on both scientific and clinical grounds. Specifically, TWA's capacity to assess risk for malignant arrhythmias has been shown to rest on sound electrophysiologic principles and AECG-based TWA monitoring can be performed in the flow of routine clinical evaluation. This review addresses: (1) electrophysiologic and ionic mechanisms underlying TWA's predictivity, (2) principles and practical aspects of AECG-based TWA monitoring, (3) clinical evidence supporting this approach to SCD risk stratification, and (4) current and potential applications in guiding medical therapy. |
12,466 | Prognostic significance of ambulatory ECG monitoring for ventricular arrhythmias. | Ventricular arrhythmia can be detected in ambulatory ECG monitoring in individuals with or without cardiac disease, and its prognostic value varies, depending on the underlying condition. The use of continuous or intermittent ambulatory ECG monitoring can be helpful for diagnosis when there is a high pre-test probability of identifying a transient arrhythmia. In addition, Holter monitoring can be used for risk stratification of patients, in the context of the prognostic value of non-sustained ventricular arrhythmias in various clinical settings, as discussed in detail. |
12,467 | The relationship between paroxysmal atrial fibrillation and coronary artery spasm. | Coronary artery spasm has recently been reported as a complication of the ablation of atrial fibrillation (AF). It may be induced by cardiac autonomic nervous dysfunction during radiofrequency catheter ablation of AF. However, the underlying mechanism is not clear. We hypothesized that patients with paroxysmal AF coincidentally exhibit coronary artery spasm.</AbstractText>A total of 51 patients were enrolled in a case control study to clarify the relationship between paroxysmal AF and coronary artery spasm. We evaluated 17 patients with paroxysmal AF (AF group) and 34 patients without paroxysmal AF (control group). Drug-induced coronary artery spasm provocation tests were performed by intracoronary administration of acetylcholine or ergonovine.</AbstractText>The AF group consisted of nine males and eight females, mean age 67 ± 10 years. The control group consisted of 16 males and 18 females, mean age 60 ± 14 years. In the AF group, coronary artery spasm was induced in 13 patients (76.5%) before AF ablation. In the control group, coronary artery spasm was induced in three patients (8.8%). Coronary artery spasm was more frequently induced in patients with AF (76.5% vs 8.8%; odds ratio, 33.583; 95% confidence interval, 6.5732-171.58; P < 0.0001). In the AF group, ventricular fibrillation and AF were recorded immediately after right coronary artery spasm induction in one patient.</AbstractText>Paroxysmal AF patients have high positive rates of drug-provoked coronary artery spasm. Patients with paroxysmal AF may coincidentally exhibit coronary artery spasm.</AbstractText>©2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,468 | Low serum eicosapentaenoic acid level is a risk for ventricular arrhythmia in patients with acute myocardial infarction: a possible link to J-waves. | Eicosapentaenoic acid (EPA) has antiarrhythmic effects. The J-wave on an electrocardiogram is associated with a high incidence of ventricular tachycardia/fibrillation (VT/VF). We evaluated relationships between EPA and J-waves, and their involvement in the occurrence of VT/VF in acute myocardial infarction (AMI). Two hundred consecutive patients undergoing successful percutaneous coronary intervention within 12 h after AMI onset were enrolled. Serum EPA level and J-waves at admission were evaluated. The patients were divided into two groups according to the optimal cutoff value (2.94) of serum EPA level (% of total fatty acids): LOW (<2.94, 61 ± 11 years, n = 103) and HIGH groups (≥2.94, 70 ± 13 years, n = 81). J-waves were observed more frequently in the LOW (36/103, 35 %) than in HIGH group (16/81, 20 %) (P = 0.020). The 30-day incidence of VT/VF including those occurring before admission was higher in the LOW (19.5 %) than in HIGH group (6.2 %) (P = 0.009). The patients with J-waves showed a higher incidence of VT/VF (23.1 %) than those without J-waves (9.9 %) (P = 0.019). Kaplan-Meier analysis showed that the highest incidence of VT/VF was observed in the LOW with J-wave group (27.8 %), followed by the LOW without J-wave (15.0 %), HIGH with J-wave (12.5 %), and HIGH without J-wave (4.6 %) (P = 0.013). Cox proportional hazard analysis revealed that Killip grade and low serum EPA level or presence of J-waves were significantly associated with the incidence of VT/VF. Low serum EPA level is a risk for incidence of VT/VF in the acute phase of myocardial infarction. Involvement of the J-wave and its possible link with EPA in the pathogenesis of ischemia-induced VT/VF are suggested. |
12,469 | Primary percutaneous coronary intervention for refractory cardiac arrest. | The identification and treatment of reversible causes is paramount to the success of resuscitation in cardiac arrest, particularly when standard therapy has failed. Acute coronary occlusion is one such cause, and the introduction of primary percutaneous coronary intervention services may provide an opportunity for emergency revascularization in this setting. This article describes 2 patients with cardiac arrest as a result of coronary occlusion, in which standard therapeutic measures proved futile. The first patient had refractory ventricular fibrillation, and the second had an episode of ventricular fibrillation followed by true pulseless electrical activity: total cessation of ventricular activity. In both examples, external mechanical compression and primary percutaneous coronary intervention facilitated coronary revascularization and achieved return of spontaneous circulation, leading to survival to hospital discharge. |
12,470 | Burden of arrhythmias in patients with Takotsubo cardiomyopathy (apical ballooning syndrome). | The objective of our study was to assess the burden of arrhythmias, the gender differences in occurrence of arrhythmias and the impact of these arrhythmias on hospitalization outcomes in patients with Takotsubo Cardiomyopathy (TTC).</AbstractText>TTC and various arrhythmias were identified using appropriate ICD-9-CM codes from Nationwide Inpatient Sample (NIS) discharge records 2006-2010. Length of hospital stay (LOS), in-hospital mortality and total charges were used to assess the impact of the arrhythmias on TTC hospitalization. All analyses were performed using SASv9.2 (Cary Institute Inc., Cary, NC).</AbstractText>A total of 16,450 patients were included in the study and 26% (n=4296) of patients had cardiac arrhythmias. Following arrhythmias were present in the descending order of frequency: atrial fibrillation (Afib) 6.9%, ventricular tachycardia (VT) 3.2%, atrial flutter (Afl) 1.9%, ventricular fibrillation and flutter 1%, paroxysmal supraventricular tachycardia (PSVT) 0.8%. Nearly two percent of the patients had sudden cardiac arrest (SCA). Males were more likely to have cardiac arrhythmias in general compared to females (OR: 1.5, 95% CI: 1.3-1.7, p-value 0.001). Occurrence of ventricular tachycardia (OR: 1.7, 95% CI: 1.3-2.2, p-value<0.001) and sudden cardiac arrest OR: 1.6, 95% CI: 1.1-2.2, p<0.001) were significantly higher in males. In contrast, Afib was significantly less in males compared to females (OR:0.8, 95% CI:0.6-0.9). Patients with arrhythmias had significantly longer length of stay, and increased cost of hospitalization and mortality.</AbstractText>Arrhythmias are present in nearly one-quarter of patients with TTC and worsen the outcome. While TTC has been established as a disease mainly of females, life threatening arrhythmias like VT and SCA are more common in males.</AbstractText>© 2013.</CopyrightInformation> |
12,471 | Dietary omega-3 fatty acids promote arrhythmogenic remodeling of cellular Ca2+ handling in a postinfarction model of sudden cardiac death. | It has been proposed that dietary omega-3 polyunsaturated fatty acids (n-3 PUFAs) can reduce the risk of ventricular arrhythmias in post-MI patients. Abnormal Ca(2+) handling has been implicated in the genesis of post-MI ventricular arrhythmias. Therefore, we tested the hypothesis that dietary n-3 PUFAs alter the vulnerability of ventricular myocytes to cellular arrhythmia by stabilizing intracellular Ca(2+) cycling. To test this hypothesis, we used a canine model of post-MI ventricular fibrillation (VF) and assigned the animals to either placebo (1 g/day corn oil) or n-3 PUFAs (1-4 g/day) groups. Using Ca(2+) imaging techniques, we examined the intracellular Ca(2+) handling in myocytes isolated from post-MI hearts resistant (VF-) and susceptible (VF+) to VF. Frequency of occurrence of diastolic Ca(2+) waves (DCWs) in VF+ myocytes from placebo group was significantly higher than in placebo-treated VF- myocytes. n-3 PUFA treatment did not decrease frequency of DCWs in VF+ myocytes. In contrast, VF- myocytes from the n-3 PUFA group had a significantly higher frequency of DCWs than myocytes from the placebo group. In addition, n-3 PUFA treatment increased beat-to-beat alterations in the amplitude of Ca(2+) transients (Ca(2+) alternans) in VF- myocytes. These n-3 PUFAs effects in VF- myocytes were associated with an increased Ca(2+) spark frequency and reduced sarcoplasmic reticulum Ca(2+) content, indicative of increased activity of ryanodine receptors. Thus, dietary n-3 PUFAs do not alleviate intracellular Ca(2+) cycling remodeling in myocytes isolated from post-MI VF+ hearts. Furthermore, dietary n-3 PUFAs increase vulnerability of ventricular myocytes to cellular arrhythmia in post-MI VF- hearts by destabilizing intracellular Ca(2+) handling. |
12,472 | Defibrillation testing in everyday medical practice during implantable cardioverter defibrillator implantation in France: analysis from the LEADER registry. | Defibrillation testing (DT) is usually performed during implantable cardioverter defibrillator (ICD) implantation.</AbstractText>We conducted a multicentre prospective study to determine the DT procedures used in everyday practice, to compare the characteristics of patients with or without DT, and to compare severe adverse events in these two populations during implantation and follow-up.</AbstractText>The LEADER registry enrolled 904 patients included for primo-implantation of a single (n=261), dual (n=230) or triple (n=429) defibrillation system in 42 French centres.</AbstractText>Baseline characteristics of patients (62.0 ± 13.5 years; 88% men; primary indication 62%) who underwent ventricular fibrillation (VF) induction (VF induction group, n=810) and those who did not (untested group, n=94, representing 10.4% of the entire study population) revealed that the untested group were older (P<0.01), had a lower left ventricular ejection fraction, a wider QRS complex and a higher New York Heart Association class and were more often implanted for primary prevention (P<0.001 for all). The main reason given for not performing ICD testing was poor haemodynamic condition (59/94). At 1 year, the cumulative survival rate was 95% in tested patients and 85% in untested patients (P<0.001), mainly because of heart failure deaths. There was one sudden cardiac death in the VF induction group and none in the untested group (P=1.000).</AbstractText>In this study, more than 10% of ICD patients were implanted without VF induction. Untested patients appeared to be sicker than tested patients, with a more severe long-term outcome, but without any difference in mortality due to arrhythmic events.</AbstractText>Copyright © 2013 Elsevier Masson SAS. All rights reserved.</CopyrightInformation> |
12,473 | Early coronary revascularization improves 24h survival and neurological function after ischemic cardiac arrest. A randomized animal study. | Survival after out-of-hospital cardiac arrest (OHCA) remains poor. Acute coronary obstruction is a major cause of OHCA. We hypothesize that early coronary reperfusion will improve 24h-survival and neurological outcomes.</AbstractText>Total occlusion of the mid LAD was induced by balloon inflation in 27 pigs. After 5min, VF was induced and left untreated for 8min. If return of spontaneous circulation (ROSC) was achieved within 15min (21/27 animals) of cardiopulmonary resuscitation (CPR), animals were randomized to a total of either 45min (group A) or 4h (group B) of LAD occlusion. Animals without ROSC after 15min of CPR were classified as refractory VF (group C). In those pigs, CPR was continued up to 45min of total LAD occlusion at which point reperfusion was achieved. CPR was continued until ROSC or another 10min of CPR had been performed. Primary endpoints for groups A and B were 24-h survival and cerebral performance category (CPC). Primary endpoint for group C was ROSC before or after reperfusion.</AbstractText>Early compared to late reperfusion improved survival (10/11 versus 4/10, p=0.02), mean CPC (1.4±0.7 versus 2.5±0.6, p=0.017), LVEF (43±13 versus 32±9%, p=0.01), troponin I (37±28 versus 99±12, p=0.005) and CK-MB (11±4 versus 20.1±5, p=0.031) at 24-h after ROSC. ROSC was achieved in 4/6 animals only after reperfusion in group C.</AbstractText>Early reperfusion after ischemic cardiac arrest improved 24h survival rate and neurological function. In animals with refractory VF, reperfusion was necessary to achieve ROSC.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,474 | J waves in accidental hypothermia. | The J wave is an ECG marker of ventricular fibrillation. However, the prevalence and clinical implications of J waves in hypothermic patients remain unclear.</AbstractText>We evaluated the clinical characteristics and ECGs of patients who were admitted for accidental hypothermia (<35.0°C). J waves were defined as notches or slurs in the terminal part of the QRS complex with an amplitude ≥0.1mV. We analyzed the prevalence of J waves and the relationship between body temperature (BT) and J wave amplitude. We also examined the augmentation of J waves following variable R-R intervals in patients with atrial fibrillation. Furthermore, we assessed the incidence of ventricular arrhythmias. A total of 60 hypothermic patients were recruited (mean age, 64±9 years; 97% male). The mean BT was 31.3°C (range, 29.4-33.5°C). J waves, which disappeared after rewarming, were observed in 30 patients (50%), with a higher frequency in patients with lower BT. Higher amplitude of J waves was associated with lower BT (P<0.001). Of the 8 patients with J waves and atrial fibrillation, 4 exhibited an augmentation of J waves following a short R-R interval. Only 1 patient with J waves developed ventricular tachycardia during rewarming.</AbstractText>The prevalence of J waves and their amplitude increased with the severity of hypothermia. The temporal development of J waves might not be associated with fatal arrhythmic events.</AbstractText> |
12,475 | Characteristics of a large sample of candidates for permanent ventricular pacing included in the Biventricular Pacing for Atrio-ventricular Block to Prevent Cardiac Desynchronization Study (BioPace). | The general clinical profile of European pacemaker recipients who require predominant ventricular pacing (VP) is scarcely known. We examined the demographic and clinical characteristics of the 1808 participants (out of 1833 randomized patients) of the ongoing Biventricular Pacing for Atrio-ventricular Block to Prevent Cardiac Desynchronization (BioPace) study.</AbstractText>BioPace recruited patients between May 2003 and September 2007 predominantly in European medical centres. We analysed demographic data and described clinical characteristics and electrophysiological parameters prior to device implantation in 1808 enrolled patients. The mean age ± standard deviation (SD) of the 1808 patients was 73.5 ± 9.2 years, 1235 (68%) were men, 654 (36%) presented without structural heart disease, 547 (30%) had ischemic, 355 (20%) hypertensive, 146 (8%) valvular, and 102 (6%) non-ischemic dilated cardiomyopathy. Mean left ventricular ejection fraction was 55.4 ± 12.3%. The main pacing indications were (a) permanent and intermittent atrioventricular (AV) block in 973 (54%), (b) atrial fibrillation with slow ventricular rate in 313 (17%), and (c) miscellaneous bradyarrhythmias in 522 (29%) patients. Mean QRS duration was 118.5 ± 30.5 ms, left bundle branch block was present in 316 (17%), and atrial tachyarrhythmias in 426 (24%) patients.</AbstractText>To the best of our knowledge, this sample is a representative source of description of the general profile of European pacemaker recipients who require predominant VP. Patients' characteristics included advanced age, predominantly male gender, preserved left ventricular systolic function, high-grade AV block, narrow QRS complex, and atrial tachyarrhythmias, the latter being present in nearly one-fourth of the cohort.</AbstractText> |
12,476 | Classic Osborn waves and incessant ventricular fibrillation in severe hypothermia. | Cardiac arrhythmias in severe hypothermia are common and are managed primarily by re-warming techniques. A 64-year-old male presented with alcohol associated aspiration pneumonia, sepsis and severe hypothermia and was noted to have classic ECG changes of hypothermia, i.e. Osborn waves. The patient had a tumultuous clinical course with prolonged resuscitative measures. Ultimately, an early focus on invasive core temperature re-warming with cardio-pulmonary bypass resulted in a favorable outcome. |
12,477 | Role of small-conductance calcium-activated potassium channels in atrial electrophysiology and fibrillation in the dog. | Recent evidence points to functional Ca²⁺-dependent K⁺ (SK) channels in the heart that may govern atrial fibrillation (AF) risk, but the underlying mechanisms are unclear. This study addressed the role of SK channels in atrial repolarization and AF persistence in a canine AF model.</AbstractText>Electrophysiological variables were assessed in dogs subjected to atrial remodeling by 7-day atrial tachypacing (AT-P), as well as controls. Ionic currents and single-channel properties were measured in isolated canine atrial cardiomyocytes by patch clamp. NS8593, a putative selective SK blocker, suppressed SK current with an IC₅₀ of ≈5 μmol/L, without affecting Na⁺, Ca²⁺, or other K⁺ currents. Whole-cell SK current sensitive to NS8593 was significantly larger in pulmonary vein (PV) versus left atrial (LA) cells, without a difference in SK single-channel open probability (P(o)), whereas AT-P enhanced both whole-cell SK currents and single-channel P(o). SK-current block increased action potential duration in both PV and LA cells after AT-P; but only in PV cells in absence of AT-P. SK2 expression was more abundant at both mRNA and protein levels for PV versus LA in control dogs, in both control and AT-P; AT-P upregulated only SK1 at the protein level. Intravenous administration of NS8593 (5 mg/kg) significantly prolonged atrial refractoriness and reduced AF duration without affecting the Wenckebach cycle length, left ventricular refractoriness, or blood pressure.</AbstractText>SK currents play a role in canine atrial repolarization, are larger in PVs than LA, are enhanced by atrial-tachycardia remodeling, and appear to participate in promoting AF maintenance. These results are relevant to the potential mechanisms underlying the association between SK single-nucleotide polymorphisms and AF and suggest SK blockers as potentially interesting anti-AF drugs.</AbstractText> |
12,478 | Characteristics and outcomes of sudden cardiac arrest during sports in women. | No specific data are available on characteristics and outcome of sudden cardiac death (SCD) during sport activities among women in the general population.</AbstractText>From a prospective 5-year national survey, involving 820 subjects 10 to 75 years old who presented with SCD (resuscitated or not) during competitive or recreational sport activities, 43 (5.2%) such events occurred in women, principally during jogging, cycling, and swimming. The level of activity at the time of SCD was moderate to vigorous in 35 cases (81.4%). The overall incidence of sport-related SCD, among 15- to 75-year-old women, was estimated as 0.59 (95% confidence interval [CI], 0.39-0.79) to 2.17 (95% CI, 1.38-2.96) per year per million female sports participants for the 80th and 20th percentiles of reporting districts, respectively. Compared with men, the incidence of SCDs in women was dramatically lower, particularly in the 45- to 54-year range (relative risk, 0.033; 95% CI, 0.015-0.075). Despite similar circumstances of occurrence, survival at hospital admission (46.5%; 95% CI, 31.0-60.0) was significantly higher than that for men (30.0%; 95% CI, 26.8-33.2; P=0.02), although this did not reach statistical significance for hospital discharge. Favorable neurological outcomes were similar (80%). Cause of death seemed less likely to be associated with structural heart disease in women compared with men (58.3% versus 95.8%; P=0.003).</AbstractText>Sports-related SCDs in women participants seems dramatically less common (up to 30-fold less frequent) compared with men. Our results also suggest a higher likelihood of successful resuscitation as well as less frequency of structural heart disease in women compared with men.</AbstractText> |
12,479 | Antagonistic effects of tetrodotoxin on aconitine-induced cardiac toxicity. | Aconitine, well-known for its high cardiotoxicity, causes severe arrhythmias, such as ventricular tachycardia and ventricular fibrillation, by opening membrane sodium channels. Tetrodotoxin, a membrane sodium-channel blocker, is thought to antagonize aconitine activity. Tetrodotoxin is a potent blocker of the skeletal muscle sodium-channel isoform Na(v)1.4 (IC50 10 nM), but micromolar concentrations of tetrodotoxin are required to inhibit the primary cardiac isoform Na(v)1.5. This suggests that substantial concentrations of tetrodotoxin are required to alleviate the cardiac toxicity caused by aconitine. To elucidate the interaction between aconitine and tetrodotoxin in the cardiovascular and respiratory systems, mixtures of aconitine and tetrodotoxin were simultaneously administered to mice, and the effects on electrocardiograms, breathing rates, and arterial oxygen saturation were examined. Compared with mice treated with aconitine alone, some mice treated with aconitine-tetrodotoxin mixtures showed lower mortality rates and delayed appearance of arrhythmia. The decreased breathing rates and arterial oxygen saturation observed in mice receiving aconitine alone were alleviated in mice that survived after receiving the aconitine-tetrodotoxin mixture; this result suggests that tetrodotoxin is antagonistic to aconitine. When the tetrodotoxin dose is greater than the dose that can block tetrodotoxin-sensitive sodium channels, which are excessively activated by aconitine, tetrodotoxin toxicity becomes prominent, and the mortality rate increases because of the respiratory effects of tetrodotoxin. In terms of cardiotoxicity, mice receiving the aconitine-tetrodotoxin mixture showed minor and shorter periods of change on electrocardiography. This finding can be explained by the recent discovery of tetrodotoxin-sensitive sodium-channel cardiac isoforms (Na(v)1.1, 1.2, 1.3, 1.4 and 1.6). |
12,480 | Directed acyclic graphs helped to identify confounding in the association of disability and electrocardiographic findings: results from the KORA-Age study. | To examine the association between electrocardiographic (ECG) findings and disability status in older adults.</AbstractText>KORA-Age, a population-based cross-sectional study of the MONICA/KORA project, a randomized sample from Southern Germany of people aged 65 years or older.</AbstractText>A total of 534 (51.5%) of 1,037 participants were characterized as disabled. Disabled participants were on average 4.5 years older than those who were not disabled. Crude associations of left-axis deviation, ventricular conduction defects, atrial fibrillation, and QT prolongation with disability status were significant (P < 0.05). In models controlled for age and sex, these effects remained constant except for QT prolongation. In the models adjusted for the minimal sufficient adjustment set (consisting of the variables sex, physical activity, age, obesity, diabetes, education, heart diseases, income, lung diseases, and stroke) identified by a directed acyclic graph (DAG), no significant association could be shown.</AbstractText>Associations between specific ECG findings and disability were found in unadjusted analysis and logistic models adjusted for age and sex. However, when adjusting for other possible confounders identified by the DAG, all these associations were no longer significant. It is important to adequately identify confounding in such settings.</AbstractText>Copyright © 2014 Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,481 | Ventricular arrhythmias: state of the art. | The management of ventricular tachycardia and ventricular fibrillation in the cardiac intensive care unit can be complex. These arrhythmias have many triggers, including ischemia, sympathetic stimulation, and medication toxicities, as well as many different substrates, ranging from ischemic and nonischemic cardiomyopathies to rare genetic conditions such as Brugada syndrome and long QT syndrome. Different settings, such as congenital heart disease, postoperative ventricular arrhythmias, and ventricular assist devices, increase the complexity of management. This article reviews the variety of situations and cardiac conditions that give rise to ventricular arrhythmias, focusing on inpatient management strategies. |
12,482 | The intersection of atrial fibrillation and heart failure in a hospitalised population. | This work set out to comprehensively characterize patients admitted to hospital with both atrial fibrillation (AF) and heart failure (HF) and to compare this cohort of patients to the global hospital population of patients with only one of these diagnoses.</AbstractText>This was a retrospective analysis of all in-patients with HF and AF admitted to a large urban hospital over a 3-month period. Patients with AF were identified by both discharge codes and electrocardiograms. HF patients were identified by means of discharge codes for HF and by screening all patients with AF, a common comorbidity of HF. Evidence for left ventricular (LV) dysfunction was sought. Of patients with AF (n = 453), 43% had symptoms of HF and LV dysfunction. Of patients with a discharge code and confirmed HF (n = 286), 34% had AF, 60% of whom were in chronic AF. Compared to HF patients in sinus rhythm those in AF were older (70 +/- 10 y vs 67 +/- 12 y, P < 0.02), had a higher prevalence of valvular heart disease (25% vs 7%, P < 0.0001) and a lower prevalence of ischaemic heart disease (17% vs 40%, P < 0.0001). HF patients identified by discharge codes in AF were more likely to have QRS > or = 120 msec (18% vs 12% in sinus rhythm; P= ns). Patients with AF and deemed to suffer concomitant HF, as opposed to AF alone, were significantly more likely to have QRS prolongation (QRS > or = 120 msec 27% vs 8%, P < 0.05). 8% of patients with AF and HF had a QRS > 150 msec.</AbstractText>AF and HF are frequent, concomitant pathologies in a hospitalised population. AF complicates HF assessment and treatment. Greater dyssynchrony, as denoted by ECG, in the AF and HF population suggests opportunities for treatment of HF by cardiac resynchronization therapy and ablative therapies.</AbstractText> |
12,483 | Ventricular fibrillation-induced cardiac arrest in the rat as a model of global cerebral ischemia. | Cardiopulmonary arrest remains one of the leading causes of death and disability in Western countries. Although ventricular fibrillation (VF) models in rodents mimic the "square wave" type of insult (rapid loss of pulse and pressure) commonly observed in adult humans at the onset of cardiac arrest (CA), they are not popular because of the complicated animal procedure, poor animal survival and thermal injury. Here we present a modified, simple, reliable, ventricular fibrillation-induced rat model of CA that will be useful in studying mechanisms of CA-induced delayed neuronal death as well as the efficacy of neuroprotective drugs. CA was induced in male Sprague Dawley rats using a modified method of von Planta et al. In brief, VF was induced in anesthetized, paralyzed, mechanically ventilated rats by an alternating current delivered to the entrance of the superior vena cava into the heart. Resuscitation was initiated by administering a bolus injection of epinephrine and sodium bicarbonate followed by mechanical ventilation and manual chest compressions and countershock with a 10-J DC current. Neurologic deficit score was higher in the CA group compared to the sham group during early reperfusion periods, suggesting brain damage. Significant damage in CA1 hippocampus (21% normal neurons compared to control animals) was observed following histopathological assessment at seven days of reperfusion. We propose that this method of VF-induced CA in rat provides a tool to study the mechanism of CA-induced neuronal death without compromising heart functions. |
12,484 | Brugada syndrome 1992-2012: 20 years of scientific excitement, and more. | This article describes recent progress on a novel disease that started as a scientific curiosity and has not yet found its end as a scientific revolution. |
12,485 | Kidney protection by hypothermic total liquid ventilation after cardiac arrest in rabbits. | Total liquid ventilation (TLV) with perfluorocarbons has been shown to induce rapid protective cooling in animal models of myocardial ischemia and cardiac arrest, with improved neurological and cardiovascular outcomes after resuscitation. In this study, the authors hypothesized that hypothermic TLV can also limit kidney injury after cardiac arrest.</AbstractText>Anesthetized rabbits were submitted to 15 min of untreated ventricular fibrillation. After resuscitation, three groups of eight rabbits each were studied such as (1) life support plus hypothermia (32°-33 °C) induced by cold TLV (TLV group), (2) life support without hypothermia (control group), and (3) Sham group (no cardiac arrest). Life support was continued for 6 h before euthanasia and kidney removal.</AbstractText>Time to target esophageal temperature was less than 5 min in the TLV group. Hypothermia was accompanied by preserved renal function in the TLV group as compared with control group regarding numerous markers including creatinine blood levels (12 ± 1 vs. 16 ± 2 mg/l, respectively; mean ± SEM), urinary N-acetyl-β-(D)-glucosaminidase (1.70 ± 0.11 vs. 3.07 ± 0.10 U/mol of creatinine), γ-glutamyltransferase (8.36 ± 0.29 vs. 12.96 ± 0.44 U/mol of creatinine), or β2-microglobulin (0.44 ± 0.01 vs. 1.12 ± 0.04 U/mol of creatinine). Kidney lesions evaluated by electron microscopy and conventional histology were also attenuated in TLV versus control groups. The renal-protective effect of TLV was not related to differences in delayed inflammatory or immune renal responses because transcriptions of, for example, interferon-γ, tumor necrosis factor-α, interleukin-1β, monocyte chemoattractant protein-1, toll-like receptor-2, toll-like receptor-4, and vascular endothelial growth factor were similarly altered in TLV and control versus Sham.</AbstractText>Ultrafast cooling with TLV is renal protective after cardiac arrest and resuscitation, which could increase kidney availability for organ donation.</AbstractText> |
12,486 | Radial artery catheterization causes pacemaker oversensing in rate-adaptive cardiac pacemakers. | Cardiac catheterization from radial artery access is observed to cause increased heart rate via oversensing in ipsilateral rate adaptive pacemaker. The mechanism of this phenomenon is discussed. This interaction was not observed in the setting of an implanted cardiac defibrillator. |
12,487 | The neuroprotective effect of magnesium sulphate during iatrogenically-induced ventricular fibrillation. | We studied the neuroprotective effect of magnesium sulphate (MgSO4) administered before ventricular fibrillation was induced for internal cardioverter defibrillator threshold testing, and continued during reperfusion.</AbstractText>With the intention of increasing serum magnesium (Mg) to >1.2 mmol/L, 15 patients received 16 mmol of MgSO4, IV, followed by 5 mmol over two hours. Fifteen patients received placebo. Serum neuron-specific enolase (NSE) was assessed, as well as pre- and postoperative neurocognitive function.</AbstractText>NSE increased in all patients, reaching a peak at 24 hours. The target Mg level was maintained throughout surgery in only nine of the Mg patients, and mainly in those with low lean body mass (LBM). In these patients, increased Mg levels were related to altered NSE release (P<0.05). NSE increased when serum Mg dropped to <1.2 mmol/L, finally exceeding levels of inadequately or untreated patients. Neurocognitive function after surgery was similar between groups.</AbstractText>Insufficient dosing could account for our results, as NSE release could be inhibited by Mg >1.2 mmol/L. For neuroprotection, the Mg dosage should be adjusted according to LBM and infusion be extended to >2 hours.</AbstractText> |
12,488 | The CURE-AF trial: a prospective, multicenter trial of irrigated radiofrequency ablation for the treatment of persistent atrial fibrillation during concomitant cardiac surgery. | Ablation technology has been introduced to replace the surgical incisions of the Cox-Maze procedure in order to simplify the operation. However, the efficacy of these ablation devices has not been prospectively evaluated.</AbstractText>The purpose of this study was to examine the efficacy and safety of irrigated unipolar and bipolar radiofrequency ablation for the treatment of persistent and long-standing persistent atrial fibrillation (AF) during concomitant cardiac surgical procedures.</AbstractText>Between May 2007 and July 2011, 150 consecutive patients were enrolled at 15 U.S. centers. Patients were followed for 6 to 9 months, at which time a 24-hour Holter recording and echocardiogram were obtained. Recurrent AF was defined as any atrial tachyarrhythmia (ATA) lasting over 30 seconds on the Holter monitor. The safety end-point was the percent of patients who suffered a major adverse event within 30 days of surgery. All patients underwent a biatrial Cox-Maze lesion set.</AbstractText>Operative mortality was 4%, and there were 4 (3%) 30-day major adverse events. Overall freedom from ATAs was 66%, with 53% of patients free from ATAs and also off antiarrhythmic drugs at 6 to 9 months. Increased left atrial diameter, shorter total ablation time, and an increasing number of concomitant procedures were associated with recurrent AF (P <.05).</AbstractText>Irrigated radiofrequency ablation for treatment of AF during cardiac surgery was associated with a low complication rate. No device-related complications occurred. The Cox-Maze lesion set was effective at restoring sinus rhythm and had higher success rates in patients with smaller left atrial diameters and longer ablation times.</AbstractText>© 2013 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.</CopyrightInformation> |
12,489 | Reoperative aortic valve replacement in the octogenarians-minimally invasive technique in the era of transcatheter valve replacement. | Reoperative aortic valve replacement (re-AVR) in octogenarians is considered high risk and therefore might be indicated for transcatheter AVR. The minimally invasive technique for re-AVR limits dissection and might benefit this patient population. We report the outcomes of re-AVR in high-risk octogenarians who might be considered candidates for transcatheter AVR to assess the safety of re-AVR and minimally invasive operative techniques.</AbstractText>We identified 105 patients, aged ≥80 years, who underwent open re-AVR at our institution from July 1997 to December 2011. Patients requiring concomitant coronary bypass surgery and/or other valve surgery were excluded. The outcomes of interest included operative mortality, postoperative complications, and midterm postoperative survival.</AbstractText>Of the 105 patients, 51 underwent minimally re-AVR through upper hemisternotomy (Mre-AVR) and 54 standard full sternotomy (Fre-AVR). The mean patient age was 82.8 ± 3.8 years. No significant differences were found in the patient risk factors. Postoperatively, 6 patients (5.7%) underwent reoperation for bleeding, 4 (3.8%) experienced permanent stroke, 4 (3.8%) developed new renal failure, and 22 (21.0%) had new-onset atrial fibrillation. Overall, the operative mortality was 6.7%, and the 1- and 5-year survival was 87% and 53%, respectively. When Mre-AVR and Fre-AVR were compared, the operative mortality was 9.2% in the Fre-AVR group and 3.9% in the Mre-AVR group (P = .438). Kaplan-Meier analysis showed a survival benefit at both 1 year (79% ± 11.7% vs 92% ± 7.8%) and 5 years (38% ± 17.6% vs 65% ± 15.7%, P = .028) favoring Mre-AVR. Cox regression analysis identified heparin-induced thrombocytopenia, reoperation for bleeding, older age, full sternotomy, and an infectious complication as predictors of mortality.</AbstractText>Octogenarians who undergo re-AVR are thought to be high-risk surgical candidates. The present single-center series revealed acceptable in-hospital outcomes and operative mortality. Mre-AVR was associated with better survival compared with Fre-AVR and might benefit this population.</AbstractText>Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
12,490 | Differential interaction of clinical characteristics with key functional parameters in heart failure with preserved ejection fraction--results of the Aldo-DHF trial. | To investigate the interaction of clinical characteristics with disease characterising parameters in heart failure with preserved ejection fraction (HFpEF). Methods and results In the multicenter, randomized, placebo-controlled, double-blinded, Aldo-DHF trial investigating the effects of spironolactone on exercise capacity (peakVO2) and diastolic function (E/e') n=422 patients with HFpEF (age 67 ± 8 years, 52% females, LVEF 67 ± 8%) were included. After multiple adjustment, higher age was significantly related to reduced peakVO2, and to increased E/e', NT-proBNP, LAVI as well as LVMI (all p<0.05). Female gender (p<0.001), CAD (p=0.002), BMI (p<0.001), sleep apnoea (p=0.02), and chronotropic incompetence (CI, p=0.002) were related to lower peakVO2 values. Higher pulse pressure (p=0.04), lower heart rates (p=0.03), CI (p=0.03) and beta-blocker treatment (p=0.001) were associated with higher E/e'. BMI correlated inversely (p=0.03), whereas atrial fibrillation (p<0.001), lower haemoglobin levels (p<0.001), CI (p=0.02), and beta-blocker treatment (p<0.001) were associated with higher NT-proBNP. After multiple adjustment for demographic and clinical variables peakVO2 was not significantly associated with E/e' (r=+0.01, p=0.87), logNT-proBNP (r=0.09, p=0.08), LAVI (r=+0.03, p=0.55), and LVMI (r=+0.05, p=0.37). The associations of E/e' with logNT-proBNP (r=0.21, p<0.001), LAVI (r=+0.29, p<0.001) and LVMI (r=0.09, p=0.06) were detectable also after multiple adjustment.</AbstractText>Demographic and clinical characteristics differentially interact with exercise capacity, resting left ventricular filling index, neurohumoral activation, and left atrial and ventricular remodelling in HFpEF. Exercise intolerance in HFpEF is multi-factorial and therapeutic approaches addressing exercise capacity should therefore not only aim to improve single pathological mechanisms.</AbstractText>ISRCTN94726526 (http://www.controlled-trials.com), Eudra-CT-number 2006-002605-31.</AbstractText>© 2013. Published by Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,491 | Ventricular fibrillation after bortezomib therapy in a patient with systemic amyloidosis. | A 64-year-old female was diagnosed with systemic amyloidosis associated with multiple myeloma. Bortezomib and dexamethasone-therapy was initiated; however, she developed lethal ventricular fibrillation (VF) and cardiac arrest after 84 hours of therapy. Cardiopulmonary resuscitation using direct current shocks with epinephrine and amiodarone was initiated but failed to receive cardiac function. Although her arterial pulsations recovered immediately after the injection of vasopressin, she died of heart failure 8 hours after the onset of VF. Cardiac amyloidosis was verified by autopsy. Although the direct association of bortezomib with lethal VF remained to be clarified in our patient, the current report emphasizes on bortezomib as a substantial risk factor for cardiomyocyte damage. The potential risk of lethal events associated with cardiac amyloidosis should be carefully considered during bortezomib treatment for patients with AL amyloidosis. |
12,492 | Gene expression and genetic variation in human atria. | The human left and right atria have different susceptibilities to develop atrial fibrillation (AF). However, the molecular events related to structural and functional changes that enhance AF susceptibility are still poorly understood.</AbstractText>The purpose of this study was to characterize gene expression and genetic variation in human atria.</AbstractText>We studied the gene expression profiles and genetic variations in 53 left atrial and 52 right atrial tissue samples collected from the Myocardial Applied Genomics Network (MAGNet) repository. The tissues were collected from heart failure patients undergoing transplantation and from unused organ donor hearts with normal ventricular function. Gene expression was profiled using the Affymetrix GeneChip Human Genome U133A Array. Genetic variation was profiled using the Affymetrix Genome-Wide Human SNP Array 6.0.</AbstractText>We found that 109 genes were differentially expressed between left and right atrial tissues. A total of 187 and 259 significant cis-associations between transcript levels and genetic variants were identified in left and right atrial tissues, respectively. We also found that a single nucleotide polymorphism at a known AF locus, rs3740293, was associated with the expression of MYOZ1 in both left and right atrial tissues.</AbstractText>We found a distinct transcriptional profile between the right and left atrium and extensive cis-associations between atrial transcripts and common genetic variants. Our results implicate MYOZ1 as the causative gene at the chromosome 10q22 locus for AF.</AbstractText>© 2014 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.</CopyrightInformation> |
12,493 | Course of quantitative ventricular fibrillation waveform measure and outcome following out-of-hospital cardiac arrest. | Quantitative measures of the ventricular fibrillation waveform at the outset of resuscitation are associated with survival. However, little is known about the course of these measures during resuscitation and how this course is related to outcome.</AbstractText>The purpose of this study was to determine how waveform measures change over the course of resuscitation and whether these changes might be used to guide resuscitation.</AbstractText>We evaluated 390 persons treated by emergency providers following out-of-hospital ventricular fibrillation arrest. We assessed the ventricular fibrillation waveform using the amplitude spectrum area (AMSA) from the defibrillator's continuous electrocardiogram measured before each of the first three shocks. We used logistic regression to evaluate the relationship of AMSA and the change in AMSA with favorable neurologic survival as determined by the Cerebral Performance Category at hospital discharge 1-2.</AbstractText>Of the 390 patients who received an initial shock, 273 required a second shock and 210 required a third shock. The mean (standard deviation) for AMSA was 9.64 (0.52) for the 873 total shock cycles. AMSA₁ measured before the first shock was strongly associated with favorable neurologic survival (odds ratio [OR] 3.40, 95% confidence interval [CI] [2.48, 4.66] for 1 SD change). We observed a similar relationship for second-shock AMSA₂ (OR 3.53, 95% CI [2.42, 5.14]) and third-shock AMSA₃ (OR 3.10, 95% CI [2.03, 4.73]). The median change in AMSA was 0.24 for ΔAMSA₁₋₂ and 0.21 for ΔAMSA₂₋₃. A positive median change in AMSA between shocks was associated with favorable neurologic survival (OR 1.44, 95% CI [1.16, 1.80] for ΔAMSA₁₋₂ and OR 1.31, 95% CI [1.01, 1.71] for ΔAMSA₂₋₃).</AbstractText>Given their prognostic and dynamic qualities, quantitative waveform measures may provide an effective real-time strategy to guide individual treatment and improve survival.</AbstractText>© 2014 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.</CopyrightInformation> |
12,494 | Mutation of KCNJ8 in a patient with Cantú syndrome with unique vascular abnormalities - support for the role of K(ATP) channels in this condition. | KCNJ8 (NM_004982) encodes the pore forming subunit of one of the ATP-sensitive inwardly rectifying potassium (KATP) channels. KCNJ8 sequence variations are traditionally associated with J-wave syndromes, involving ventricular fibrillation and sudden cardiac death. Recently, the KATP gene ABCC9 (SUR2, NM_020297) has been associated with the multi-organ disorder Cantú syndrome or hypertrichotic osteochondrodysplasia (MIM 239850) (hypertrichosis, macrosomia, osteochondrodysplasia, and cardiomegaly). Here, we report on a patient with a de novo nonsynonymous KCNJ8 SNV (p.V65M) and Cantú syndrome, who tested negative for mutations in ABCC9. The genotype and multi-organ abnormalities of this patient are reviewed. A careful screening of the KATP genes should be performed in all individuals diagnosed with Cantú syndrome and no mutation in ABCC9. |
12,495 | New-onset atrial fibrillation predicts malignant arrhythmias in post-myocardial infarction patients--a Cardiac Arrhythmias and RIsk Stratification after acute Myocardial infarction (CARISMA) substudy. | After myocardial infarction (MI) the risk of sudden cardiac death due to arrhythmias is substantial.</AbstractText>The purpose of this study was to investigate if new-onset atrial fibrillation (AF) is associated with development of potential malignant brady- and tachyarrhythmias after an acute MI.</AbstractText>The study included 277 post-MI patients from the CARISMA study with left ventricular ejection fraction ≤ 40%, New York Heart Association class I, II, or III and no history of AF. All patients were implanted with an implantable cardiac monitor within 4 to 27 days after an acute MI and followed every 3 months for 2 years. Time-dependent association between new-onset AF > 30 s and the development of bradyarrhythmias and/or ventricular tachyarrhythmias were investigated using Cox proportional hazard regressions.</AbstractText>New-onset AF was associated with an increased risk of bradyarrhythmias when adjusting for male gender and baseline age, left ventricular ejection fraction and QRS width (HR = 2.8 [1.3-5.8], P = .006). Similarly, new-onset AF predicted ventricular tachyarrhythmias when adjusting for New York Heart Association class ≥ II and baseline QRS width (HR = 2.3 [1.2-4.4], P = .019). After dividing ventricular tachyarrhythmias into subgroups of non-sustained ventricular tachycardia (VT), sustained VT and ventricular fibrillation (VF), new-onset AF was significantly associated with an increased risk of non-sustained- and sustained VT but not VF (non-sustained VT: HR = 3.5 [1.7-7.2], P < .001, sustained VT: HR = 4.2 [1.1-15.7], P = .035, VF: HR = 1.1 [0.2-5.8], P = .877).</AbstractText>In patients surviving a MI with reduced left ventricular systolic function, new-onset AF is associated with a significantly increased risk of developing ventricular brady- and tachyarrhythmias.</AbstractText>© 2013.</CopyrightInformation> |
12,496 | Predicting early left ventricular dysfunction after mitral valve reconstruction: the effect of atrial fibrillation and pulmonary hypertension. | The preoperative ejection fraction (EF) and left ventricular (LV) end-systolic dimension are known predictors of postoperative LV dysfunction after mitral valve repair. We investigated the effect of a preoperative history of atrial fibrillation and moderate pulmonary hypertension (defined as pulmonary artery systolic pressure >50 mm Hg) on early postoperative LV dysfunction.</AbstractText>From 2003 to 2010, 632 patients who had undergone successful mitral valve repair surgery for degenerative disease were included in the present study. The preoperative and postoperative echocardiographic data and postoperative outcomes were collected retrospectively. We analyzed the demographic, hemodynamic, and echocardiographic parameters to assess the predictors of early postoperative LV dysfunction, defined as an LVEF <50%.</AbstractText>The mean age of the cohort was 57 ± 13 years. All patients had less than mild mitral regurgitation on postoperative echocardiography. After mitral valve repair, a significant decrease in the LVEF (60% ± 8% to 54% ± 9%), LV end-systolic diameter (36 ± 7 mm to 33 ± 7 mm), and LV end-diastolic dimension (56 ± 8 mm to 48 ± 7 mm) was observed at early postoperative echocardiography (P < .001). On multivariate regression analysis, preoperative atrial fibrillation, pulmonary hypertension, and LV end-systolic dimension were independent predictors of the postoperative LVEF (P = .035 and P < .001, respectively). Preoperative atrial fibrillation (odds ratio, 1.97; 95% confidence interval, 1.28-3.02; P = .002) and pulmonary artery systolic pressure >50 mm Hg (odds ratio, 1.82; 95% confidence interval, 1.11-2.97; P = .017) increased the risk of postoperative LV dysfunction by almost twofold.</AbstractText>In addition to the established predictors of postoperative LV dysfunction, the presence of preoperative pulmonary hypertension and a history of atrial fibrillation in patients undergoing mitral valve repair surgery increased the risk of early postoperative LV dysfunction by almost twofold.</AbstractText>Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
12,497 | Low Voltage Electric Injury induced Atrial Fibrillation as a Presenting Feature of Wolff-Parkinson-White Syndrome: A Case Report. | Electric injury can cause a variety of cardiac arrhythmias. Atrial fibrillation as a result of such injury is very rare. We present a case of a young asymptomatic patient who developed acute atrial fibrillation with antegrade conduction over the atrioventricular bypass tract and very high ventricular rate after accidental low voltage electric injury, which was reverted successfully by DC shock. |
12,498 | Catheter Ablation of Polymorphic Ventricular Tachycardia and Ventricular Fibrillation. | Recently, catheter ablation (CA) has become a therapeutic option to target focal triggers of polymorphic ventricular tachycardia and ventricular fibrillation (VF) in the setting of electrical storm (ES). This strategy was first described in subjects without organic heart disease (i.e. idiopathic VF) and subsequently in other conditions, especially in patients with ischaemic heart disease. In the majority of cases, the triggering focus originates in the ventricular Purkinje system. In patients with Brugada syndrome, besides ablation of focal trigger in the right ventricular outflow tract, modification of a substrate in this region has been described to prevent recurrences of VF. In conclusion, CA appears to be a reasonable strategy for intractable cases of ES due to focally triggered polymorphic ventricular tachycardia and VF. Therefore, early transport of the patient into the experience centre for CA should be considered since the procedure could be in some cases life-saving. Therefore, the awareness of this entity and link to the nearest expert centre are important. |
12,499 | What About Tachycardia-induced Cardiomyopathy? | Long-standing tachycardia is a well-recognised cause of heart failure and left ventricular dysfunction, and has led to the nomenclature, tachycardia-induced cardiomyopathy (TIC). TIC is generally a reversible cardiomyopathy if the causative tachycardia can be treated effectively, either with medications, surgery or catheter ablation. The diagnosis is usually made after demonstrating recovery of left ventricular function with normalisation of heart rate in the absence of other identifiable aetiologies. One hundred years after the first reported case of TIC, our understanding of the pathophysiology of TIC in humans remains limited despite extensive work in animal models of TIC. In this review we will discuss the proposed mechanisms of TIC, the causative tachyarrhythmias and their treatment, outcomes for patients diagnosed with TIC, and future directions for research and clinical care. |
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