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7,100 | Junior physician skill and behaviour in resuscitation: a simulation study. | Physicians are expected to manage their role as teamleader during resuscitation. During inter-hospital transfer the physician has the highest medical credentials on a small team. The aim of this study was to describe physician behaviour as teamleaders in a simulated cardiac arrest during inter-hospital transfer. Our goal was to pinpoint deficits in knowledge and skill integration and make recommendations for improvements in education.</AbstractText>An ambulance was the framework for the simulation; the scenario a patient with acute coronary syndrome suffering ventricular fibrillation during transportation. Physicians (graduation age < or =5 years) working in internal medicine departments in Denmark were studied. The ambulance crew was instructed to be passive to clarify the behaviour of the physicians.</AbstractText>72 physicians were studied. Chest compressions were initiated in 71 cases, ventilation and defibrillation in 72. The median times for arrival of the driver in the patient cabin, initiation of ventilation and chest compressions, and first defibrillation were all less than 1min. Medication was administered in 63/72 simulations (88%), after a median time of 210 s. Adrenaline was the preferred initial drug administered (58/63, 92%). Tasks delegated were ventilations, chest compressions, defibrillation, and administration of medication (97%, 92%, 42%, and 10% of cases, respectively).</AbstractText>Junior physicians performed well with respect to the treatment given and the delegation of tasks. However, variations in the time of initiation it took for each treatment indicated lack of leadership skills. It is imperative that the education of physicians includes training in leadership.</AbstractText> |
7,101 | Adaptive neuro-fuzzy inference system for classification of ECG signals using Lyapunov exponents. | This paper describes the application of adaptive neuro-fuzzy inference system (ANFIS) model for classification of electrocardiogram (ECG) signals. Decision making was performed in two stages: feature extraction by computation of Lyapunov exponents and classification by the ANFIS trained with the backpropagation gradient descent method in combination with the least squares method. Four types of ECG beats (normal beat, congestive heart failure beat, ventricular tachyarrhythmia beat, and atrial fibrillation beat) obtained from the PhysioBank database were classified by four ANFIS classifiers. To improve diagnostic accuracy, the fifth ANFIS classifier (combining ANFIS) was trained using the outputs of the four ANFIS classifiers as input data. The proposed ANFIS model combined the neural network adaptive capabilities and the fuzzy logic qualitative approach. Some conclusions concerning the saliency of features on classification of the ECG signals were obtained through analysis of the ANFIS. The performance of the ANFIS model was evaluated in terms of training performance and classification accuracies and the results confirmed that the proposed ANFIS model has potential in classifying the ECG signals. |
7,102 | Prevalence of left atrial appendage pseudothrombus filling defects in patients with atrial fibrillation undergoing coronary computed tomography angiography. | Previous reports have shown that computed tomography (CT) is a useful, noninvasive test for detecting atrial thrombi. However, blood stasis in the left atrial appendage (LAA) of patients with atrial fibrillation (AF) may be a common cause for false-positive results.</AbstractText>We retrospectively evaluated the prevalence of filling defects that may simulate thrombus in the LAA of patients with AF during routine coronary CT angiography (CTA).</AbstractText>The LAA of 7 patients with AF was studied for the presence of filling defects and compared with 250 healthy persons. LAA volume in the patients with AF was measured at 10 different cardiac phases and compared with 30 healthy patients.</AbstractText>Of the 7 patients with AF studied with CTA, 5 were positive for LAA filling defects. Follow-up imaging studies, including transesophageal echocardiogram, contrast-enhanced magnetic resonance angiography, or delayed-CT, were negative for LAA thrombus. Of 250 patients without AF, CTA showed no evidence of LAA filling defects. Patients with AF had significantly larger LAA volumes at all cardiac phases measured compared with patients without AF (15.2 +/- 6.93 mL compared with 6.85 +/- 3.01 mL at atrial contraction [P = 0.0187], 17.4 +/- 7.76 mL compared with 9.46 +/- 3.43 mL at ventricular systole [P = 0.0351], and 14.5 +/- 5.87 mL compared with 8.48 +/- 3.10 mL at mid-diastole [P = 0.0341]). Compared with the healthy persons, the patients with AF showed reduced percentages of change in LAA volume when the atrial contraction phase was compared with other phases: 44.0% +/- 25.6% compared with 16.5% +/- 12.2% compared with ventricular systole (P = 0.0004) and 29.5% +/- 23.7% compared with -1.63% +/- 8.84% at mid-diastole (P < 0.0001).</AbstractText>Pseudothrombus filling defects are common in the LAA of patients with AF undergoing coronary CTA and should not be mistaken for real thrombus.</AbstractText> |
7,103 | Surgical treatment of chronic atrial fibrillation with conventional electrocautery in mitral valve surgery. | To evaluate the results of the surgical treatment of atrial fibrillation for ablation of the posterior left atrial wall using electrocautery in mitral valve surgery.</AbstractText>From May 2004 to December 2006, 23 patients underwent surgical correction of mitral valve disease and treatment of atrial fibrillation using the conventional electrocautery for the accomplishment of lines of endocardial ablation in the left atrium. The mean age of the patients was 59 years, and 60.8% were female. The left atrium mean diameter was 50.3 +/- 5.09 mm and the left ventricular ejection fraction was 53.6 +/- 11.03%.</AbstractText>The mean time of extracorporeal circulation was 52.5 +/- 13.3 min; aortic clamping, 35.6 +/- 12.9 min; atrial ablation, 3.05 +/- 0.16 min. All the patients were free of atrial fibrillation after the procedure; on hospital discharge, 69.5%; at 6 months, 91.3%; at 12 months, 76.4%; at 18 months, and at 24 months, 68.4%. At 12 months, left atrium mean diameter was 42.1 +/- 3.5 mm; left ventricular ejection fraction was 59.2 +/- 3.48%; In addition, left atrial contraction was present in 68.8% of the patients.</AbstractText>The surgical treatment of the atrial fibrillation with electrocautery in mitral valve surgery was capable to determine the reversion of this arrhythmia in a significant number of patients during short- and middle-term clinical follow-up without mortality and fewer complications.</AbstractText> |
7,104 | Progressing from initial non-shockable rhythms to a shockable rhythm is associated with improved outcome after out-of-hospital cardiac arrest. | Cardiac arrest patients with initial non-shockable rhythm progressing to shockable rhythm have been reported to have inferior outcome to those remaining non-shockable. We wanted to confirm this observation in our prospectively collected database, and assess whether differences in cardiopulmonary resuscitation (CPR) quality could help to explain any such difference in outcome.</AbstractText>All out-of-hospital cardiac arrest (OHCA) cases in the Oslo EMS between May 2003 and April 2008 were retrospectively studied, and cases with initial asystole or pulseless electrical activity (PEA) were selected. Pre-hospital and hospital records, Utstein forms, and continuous ECGs were reviewed. Quality of CPR and outcome were compared for patients who progressed to a shockable rhythm and patients who remained in non-shockable rhythms.</AbstractText>Of 753 cases with initial non-shockable rhythms 517 (69%) had asystole and 236 (31%) PEA. Ninety-eight (13%) patients progressed to a shockable rhythm, while 653 (87%) remained non-shockable during the entire resuscitation effort (two unknown). Hands-off ratio was higher in the shockable than the non-shockable group, 0.21+/-0.12 vs. 0.16+/-0.10 (p=0.000) with no significant difference in compression and ventilation rates. Overall survival to hospital discharge was 3%; 7% in the shockable and 2% in the non-shockable group (p=0.014). Based on a multivariate logistic analysis young age, initial PEA, and progressing to a shockable rhythm were associated with better outcome.</AbstractText>Progressing from initial non-shockable rhythms to a shockable rhythm was associated with improved outcome after OHCA. This occurred despite more pauses in chest compressions in the shockable group, probably related to defibrillation attempts.</AbstractText> |
7,105 | A national resuscitation registry of out-of-hospital cardiac arrest in Germany-a pilot study. | Survival rate after out-of-hospital cardiac arrest (OHCA) has not significantly increased over the last decade. However, survival rate has been used as a quality benchmark for many emergency medical services. A uniform resuscitation registry may be advantageous for quality management of cardiopulmonary resuscitation (CPR). This study was conducted to evaluate the establishment of a national CPR registry in Germany.</AbstractText>A prospective cohort study was performed that included 469 patients who experienced OHCA requiring CPR in the metropolitan area of Dortmund, Germany. Cardiac arrest was defined as concomitant appearance of unconsciousness, apnoea or gasping and pulselessness. All data were collected via a secure and confidential paper-based method as the data set 'Preclinical care'.</AbstractText>Quality of data was classified as 'good' in 33.4%, 'moderate' in 48.4%, and 'bad' in 18.2% of the patients, respectively. Sixty-two percent had OHCA in private residences, 24% of the patients had a first monitored rhythm of ventricular fibrillation (VF) or ventricular tachycardia (VT), 35.2% had return of spontaneous circulation (ROSC) on scene, and patients presenting VF/VT as the first monitored rhythm had higher ROSC rates (51.3%) compared to patients with asystole (22.6%).</AbstractText>The data set 'Preclinical care' proved to be congruent with the Utstein style, provided further information for national and international comparisons, and enabled a detailed analysis. Optimisation of data collection and introduction of strict control mechanisms may further improve data quality.</AbstractText> |
7,106 | Half of the patients with chest pain that are urgently referred are transported in unsafe conditions. | Patients with an acute coronary syndrome should be referred to hospital urgently to start reperfusion therapy as soon as possible. Owing to the risks of ventricular fibrillation and pulseless ventricular tachycardia, urgent transport should be organized under safe conditions, that is, with a defibrillator at hand.</AbstractText>To evaluate the type of transport of patients with chest pain referred by their general practitioner (GP).</AbstractText>Observational study.</AbstractText>A sentinel network of general practices in Belgium, covering almost 1.6% of the total population.</AbstractText>One thousand nine hundred and ninety-six patients with chest pain attending their GP in 2003.</AbstractText>Descriptive analyses reporting proportions along with their 95% confidence interval (CI).</AbstractText>Male patients were referred to hospital more often than female patients: 44.9% (95% CI: 41.6-47.8) versus 36.5% (95% CI: 33.4-39.6). For patients who were referred routinely, 92.7% (95% CI: 89.1-95.2) were transported by family and neighbours, 4.8% (95% CI: 2.8-7.9) by ambulance and 2.5% (95% CI: 1.2-5.1) by GPs. For patients who were referred urgently, ambulances transported 56.9% (95% CI: 51.1-62.7), family and neighbours 36.9% (95% CI: 31.4-42.7) and the GP 6.1% (95% CI: 3.7-9.5).</AbstractText>Almost half of the patients with chest pain who require urgent referral are transported in unsafe conditions.</AbstractText> |
7,107 | Catheter ablation for patients with ventricular fibrillation. | Ventricular fibrillation is a challenging arrhythmia for physicians, with only a limited number of treatment options available. Implantable cardioverter defibrillator therapy is the treatment of choice for patients for both primary and secondary prevention with the role of antiarrhythmic therapy aimed at reducing the number of recurrences. Catheter ablation is an accepted treatment for a number of atrial and ventricular arrhythmias, but until recently ventricular fibrillation was thought to be a bridge too far. The recent advances in ventricular fibrillation ablation will be reviewed.</AbstractText>Recent work has demonstrated that the Purkinje network is critical in the triggering and maintenance of ventricular fibrillation. Catheter ablation targeting the ventricular ectopic(s) or Purkinje potentials responsible for triggering ventricular fibrillation or both has been shown to be both possible and efficacious in a number of conditions, ranging from the Brugada syndrome to ischaemic ventricular fibrillation to idiopathic ventricular fibrillation. Although there are relatively few reports of catheter ablation of ventricular fibrillation in the literature, the method appears robust as it is being repeated by a number of different groups around the world.</AbstractText>Catheter ablation targeting ventricular ectopics and Purkinje potentials is a successful treatment for ventricular fibrillation. Although the long-term results of such procedures are awaited, the short-term results are very encouraging.</AbstractText> |
7,108 | Atrial-selective pharmacological therapy for atrial fibrillation: hype or hope? | Rhythm control remains of therapeutic value for many atrial fibrillation patients despite no evidence of survival benefit. This lack of benefit may relate to side effects of conventional antiarrhythmic drugs. The introduction of novel agents was a logical consequence.</AbstractText>Novel antiarrhythmics are currently being evaluated in preclinical or clinical studies. Among recently developed drugs, some affect one or more atrial targets, including I Kur, I KACh, INa or I SAC, allowing them to act selectively on atria over ventricles. Some drugs that exhibit atrial selectivity have not been successful in preliminary studies. Block of a single atrial-specific target may be insufficient for atrial fibrillation termination and prevention, and multichannel-blocking properties may be a useful alternate approach. Drugs such as vernakalant or ranolazine inhibit multiple channels but display effective and atrial-selective actions. Furthermore, dronedarone, a prototypic multichannel blocker with additional effects on ventricular myocardium, has proven well tolerated and effective in the treatment of atrial fibrillation and may even reduce cardiovascular mortality.</AbstractText>Efforts to develop atrial-selective antiarrhythmics are bearing fruit, but such compounds will need to exhibit equal or superior safety and efficacy compared with multichannel blockers such as dronedarone for atrial fibrillation suppression in order to prove their worth. It is still too early to tell whether atrial selectiveness is just hype or truly a hope for antiarrhythmic drug treatment of atrial fibrillation.</AbstractText> |
7,109 | Taser X26 discharges in swine: ventricular rhythm capture is dependent on discharge vector. | Data from our previous studies indicate that Taser X26 stun devices can acutely alter cardiac function in swine. We hypothesized that most transcardiac discharge vectors would capture ventricular rhythm, but that other vectors, not traversing the heart, would fail to capture the ventricular rhythm.</AbstractText>Using an Institutional Animal Care and Use Committee (IACUC) approved protocol, four Yorkshire pigs (25-36 kg) were anesthetized, paralyzed with succinylcholine (2 mg/kg), and then exposed to 10 second discharges from a police-issue Taser X26. For most discharges, the barbed darts were pushed manually into the skin to their full depth (12 mm) and were arranged in either transcardiac (such that a straight line connecting the darts would cross the region of the heart) or non-transcardiac vectors. A total of 11 different vectors and 22 discharge conditions were studied. For each vector, by simply rotating the cartridge 180-degrees in the gun, the primary current-emitting dart was changed and the direction of current flow during the discharge was reversed without physically moving the darts. Echocardiography and electrocardiograms (ECGs) were performed before, during, and after all discharges. p values < 0.05 were considered significant.</AbstractText>ECGs were unreadable during the discharges because of electrical interference, but echocardiography images clearly demonstrated that ventricular rhythm was captured immediately in 52.5% (31 of 59) of the discharges on the ventral surface of the animal. In each of these cases, capture of the ventricular rhythm with rapid ventricular contractions consistent with ventricular tachycardia (VT) or flutter was seen throughout the discharge. A total of 27 discharges were administered with transcardiac vectors and ventricular capture occurred in 23 of these discharges (85.2% capture rate). A total of 32 non-transcardiac discharges were administered ventrally and capture was seen in only eight of these (25% capture rate). Ventricular fibrillation (VF) was seen with two vectors, both of which were transcardiac. In the remaining animals, VT occurred postdischarge until sinus rhythm was regained spontaneously.</AbstractText>For most transcardiac vectors, Taser X26 caused immediate ventricular rhythm capture. This usually reverted spontaneously to sinus rhythm but potentially fatal VF was seen with two vectors. For some non-transcardiac vectors, capture was also seen but with a significantly (p < 0.0001) decreased incidence.</AbstractText> |
7,110 | The efficacy of rewarming with a portable and percutaneous cardiopulmonary bypass system in accidental deep hypothermia patients with hemodynamic instability. | Accidental deep hypothermia (ADH)--a condition in which the core body temperature is less than 28 degrees C--is a medical emergency; the mortality rates for ADH remain high. The efficacy of cardiopulmonary bypass (CPB) rewarming has been proved in ADH patients with cardiopulmonary arrest; however, its efficacy in the ADH patients without cardiopulmonary arrest remains controversial. In our study, we evaluated the efficacy of portable percutaneous cardiopulmonary bypass (PPCPB) for rewarming and providing cardiovascular support in the hemodynamically unstable ADH patients without cardiopulmonary arrest.</AbstractText>Between April 2001 and March 2006, we performed a retrospective study at Tokai University, Kanagawa, Japan. We studied 24 ADH patients without cardiopulmonary arrest (male:female ratio, 15:9; mean age, 68.5 +/- 12.9 years) with hemodynamic instability who had not developed intracranial hemorrhage. We evaluated the efficacy of PPCPB rewarming by estimating the mean time of initiation of PPCPB after admission, rewarming speed, the success rate of rewarming, the rate of weaning from PPCPB, the incidence of ventricular fibrillation (Vf) during rewarming, complications associated with PPCPB, mortality rate, and the Glasgow Outcome Scale (GOS) scores of the patients who survived.</AbstractText>The mean time of initiation of PPCPB after admission was 41.9 +/- 7.9 minutes. The rewarming speed was 4.0 +/- 1.5 degrees C/h. A 100% success rate was achieved after the rewarming procedure, whereas the rate of weaning from PPCPB was 91.7%. Vf during rewarming developed in one case; however, electrical defibrillation was possible. No direct complications of PPCPB were observed. The mortality rate was 12.5% (3/24). The GOS scores of the patients who survived were as follows: 5 points, 17 cases; 4 points, 3 cases; and 3 points, 1 case.</AbstractText>PPCPB rewarming is a clinically efficacious procedure for rewarming and providing cardiovascular support in hemodynamically unstable ADH patients without cardiopulmonary arrest who have not developed intracranial hemorrhage.</AbstractText> |
7,111 | [Spatiotemporal characteristics of activation of the heart of hibernating and non-hibernating mammals during hypothermia]. | The heart of hibernating mammals is known to demonstrate the nature\'s model of resistance to rhythm disturbances, including ventricular arrhythmias, during hypothermia. However, electrophysiological mechanism of this phenomenon is not completely understood. Using optical mapping technique with voltage-sensitive dye di-4-ANEPPS, we investigated the spatiotemporal characteristics of ventricular activation in Langendorff-perfused hearts of winter hibernating ground squirrels Spermophyllus undulatus and rabbits at temperatures from +37 degrees C to +3 degrees C. In rabbit hearts, reduction of temperature from 37 to 17 degrees C resulted in significant decrease of conduction velocity and increase of conduction anisotropy. Excitation failure was observed in the rabbit heart at 12+/-1 degree C. In contrast, ground squirrels exhibited significantly faster conduction velocity compared with rabbits at all temperatures and insensibility of conduction anisotropy to cooling down to 3C which can protect the hibernator heart against arrhythmias during hypothermia. |
7,112 | Long-term electrocardiographic follow-up from childhood of an adult patient with Brugada syndrome associated with sick sinus syndrome. | We had the unique opportunity of following the electrocardiographic (ECG) course of a 13-year-old male with sinus dysfunction and atrial flutter who subsequently developed a Brugada-type ECG pattern associated with sick sinus syndrome at 25 years old. Family history showed that the patient's mother and maternal grandfather suddenly died while sleeping at night. When the patient was 13 years old, he lost consciousness after running a marathon. The patient was diagnosed with sinus dysfunction and atrial flutter, and he underwent pacemaker implantation at 15 years old. ECG examinations performed between 13 and 20 years old showed incomplete right bundle branch block and ST elevation with early depolarization. On ECG examinations performed when the patient was 21 years old and thereafter, the V(2) lead always showed a saddleback-type ST elevation. At 25 years old, the late potential was positive and the electrophysiological study induced ventricular fibrillation. A challenge test with pilsicainide showed remarkable ST elevation by the V(2) lead. The 24-h Holter ECG monitoring showed remarkable ST elevation after eating a snack and during night time when the patient was asleep. The patient was diagnosed with Brugada syndrome and an implantable cardioverter-defibrillator was implanted. Genetic analysis did not reveal mutation of the SCN5A gene. |
7,113 | Dynamic change in ST-segment and spontaneous occurrence of ventricular fibrillation in Brugada syndrome with a novel nonsense mutation in the SCN5A gene during long-term follow-up. | A 67-year-old male underwent genetic testing under the diagnosis of Brugada syndrome because of recurrent ventricular fibrillation with coincident ST-segment elevation in either right precordial, inferior leads or both since the age of 55 years. Screening of gene mutations using denaturing high-performance liquid chromatography (DHPLC) and direct sequencing identified a novel nonsense mutation (R179X) of SCN5A in a heterozygous manner. The functional assay for the identified mutation, using a whole-cell patch clamp in the heterologous expression system, revealed that the nonsense mutation, located in the second transmembrane segment of the first domain (DI-S2) of the alpha-subunit, failed to synthesize the complete structure of the cardiac sodium channel, thus causing the non-functional channel. Coding effects by the gene mutation was altered during the 12-year follow-up, which might affect the clinical features of the patient through the ion channel density in the ventricle, dynamics of repolarization abnormality and conduction disturbance. |
7,114 | Action potential alternans in the right ventricular outflow tract in a patient with asymptomatic Brugada syndrome. | A 71-year-old man with frequent ventricular premature contractions after right hip joint surgery was referred to the Cardiology Division. Twelve-lead ECG showed type II Brugada-type ECG and signal-averaged ECG showed positive ventricular late potentials. The 12-lead ECG changed to type I Brugada-type after administration of the class Ic antiarrhythmic drug, pilsicainide. Ventricular fibrillation (VF) was reproducibly induced with double premature stimuli from the right ventricular outflow tract (RVOT) at a basic cycle length (BCL) of 400 ms. Monophasic action potentials (MAPs) recorded from the RVOT at a BCL of 400 ms showed MAP alternans and VF was only induced when extrastimuli were applied after a shorter MAP of the alternans. |
7,115 | Idiopathic ventricular fibrillation characterized by spatial heterogeneity of action potential duration and its restitution kinetics. | A 44-year-old man who had suffered multiple episodes of syncope presented with ventricular fibrillation (VF). Structural heart disease was ruled out. Programmed stimulation induced VF at the right ventricular apex (RVA) but not at the outflow tract (RVOT). Monophasic action potential duration (MAPD) at a basic cycle length of 400 msec was shorter at the RVA than at the RVOT (208 versus 231 ms). The maximum slope of the MAPD restitution curve at the 400-msec cycle length was much steeper at the RVA than at the RVOT (1.4 versus 1.0). Such spatial heterogeneity of the MAPD and of its restitution may facilitate wavebreak and functional reentry, predisposing to VF. |
7,116 | Identification of the gene causing long QT syndrome in an Israeli family. | Long QT syndrome is an inherited cardiac disease, associated with malignant arrhythmias and sudden cardiac death.</AbstractText>To map and identify the gene responsible for LQTS in an Israeli family.</AbstractText>A large family was screened for LQTS after one of them was successfully resuscitated from ventricular fibrillation. The DNA was examined for suspicious loci by whole genome screening and the coding region of the LQT2 gene was sequenced.</AbstractText>Nine family members, 6 males and 3 females, age (median and interquartile range) 26 years (13, 46), who were characterized by a unique T wave pattern were diagnosed as carrying the mutant gene. The LQTS-causing gene was mapped to chromosome 7 with the A614V mutation. All of the affected members in the family were correctly identified by electrocardiogram. Corrected QT duration was inversely associated with age in the affected family members and decreased with age.</AbstractText>Careful inspection of the ECG can correctly identify LQTS in some families. Genetic analysis is needed to confirm the diagnosis and enable the correct therapy in this disease.</AbstractText> |
7,117 | [Ebstein's anomaly as a cause of paroxysmal atrial fibrillation]. | Ebstein's anomaly is characterized by a displacement of the tricuspid valve toward apex, because of anomalous attachment of the tricuspid leaflets. There are type B of Wolff-Parkinson-White (WPW) syndrome and paroxysmal arrhythmias in more than a half of all patients.</AbstractText>We presented a female, 32-year old, with frequent paroxysms of atrial fibrillation. After conversion of rhythm an ECG showed WPW syndrome. Echocardiographic examination discovered normal size of the left cardiac chambers with paradoxical ventricular septal motion. The right ventricle was very small because of its atrialization. The origin of the tricuspid valve was 20 mm closer to apex of the right ventricle than the origin of the mitral valve. Electrophysiological examination showed a posterolateral right accesorial pathway. Atrial fibrillation was induced very easily in electrophysiological laboratory and a successful ablation of accessorial pathway was made. There were no WPW syndrome and paroxysms of atrial fibrillation after that.</AbstractText>Ebstein's anomaly is one of the reasons of paroxysmal atrial fibrillation, especially in young persons with WPW syndrome.</AbstractText> |
7,118 | Outcomes after heart valve replacement surgery at the Cardiovascular Center of Puerto Rico and the Caribbean. | Heart valve surgery is the second most common type of cardiac surgery. However, there is limited information about the outcomes associated to these types of surgeries.</AbstractText>A retrospective review was performed in 91 Puerto Rican patients who underwent elective heart valve replacement surgery at the Cardiovascular Center of Puerto Rico and the Caribbean (CCPRC) between January 2004 and January 2005. Demographic features, comorbidities, electrocardiographic findings, surgical data, length of hospitalization, and associated in-hospital complications were determined. Data were examined using Fisher's exact test, chi-square test, analysis of variance and student t test to analyze differences between the study groups.</AbstractText>The mean age of the study population was 61.1 +/- 13.2 years; 48 patients (52.7%) were males. Sixty-one patients (67.0%) had aortic valve replacement whereas thirty patients (33.0%) had mitral valve replacement. Patients with aortic valve replacement were older (63.1 +/- 13.5 years vs. 56.0 +/- 11.2 years, p < 0.05) and more likely to present left ventricular hypertrophy (57.4% vs. 16.7%, p < 0.05) than patients with mitral valve replacement. On the other hand, patients with mitral valve replacement presented more frequently atrial fibrillation (43.3% vs. 9.8%, p < 0.05) than those with aortic valve replacement. The estimated in-hospital mortality rate was 1.1%.</AbstractText>A review of heart valve replacement surgery conducted between January 2004 and January 2005 at the CCPRC revealed that the in-hospital mortality rates, complications, surgical times, and length of hospitalization at the CCPRC compares favorably with those reported in the literature.</AbstractText> |
7,119 | [Training in cardiopulmonary resuscitation: impact on the theoretical knowledge of nurses]. | This cross-sectional study aimed at evaluating the knowledge of nurses on cardiopulmonary resuscitation (CPR) as a function of the time elapsed since training was concluded. The study was performed in a general hospital in Porto Alegre, Rio Grande do Sul, during July and August, 2005. Nurses were assigned to groups 1 (33 nurses, in units equipped with a heart monitor and a cardiac defibrillator) and 2 (23 nurses, in units without this equipment). Nurses in group 1 showed better knowledge on the recognition of electrocardiographic recordings, and 91% of them recognized the ventricular fibrillation algorithm. Among nurses in group 2, 85% had knowledge on issues relative to basic care. The results showed that training in CPR generates positive results. Continued and systematic education strategies are essential to ensure better performance of the nursing team. |
7,120 | Delayed cardiac perforation by defibrillator lead placed in the right ventricular outflow tract resulting in massive pericardial effusion. | A 76-year-old man received a dual-chamber implantable cardioverter defibrillator (ICD), with the defibrillator lead positioned within the right ventricular outflow tract. The lead parameters at the time of implantation were satisfactory and the post-procedure chest X-ray showed the leads were in place. The patient was cardioverted from atrial fibrillation during defibrillation threshold testing and commenced on anticoagulation immediately. One month post implantation, he experienced multiple ventricular tachycardia episodes all successfully treated with antitachycardia pacing and shocks by his ICD, but he fell and hit his chest against a hard surface during one of these attacks. He developed a massive pericardial effusion and computed tomography confirmed cardiac perforation by the defibrillator lead. Pericardiocentesis was performed and the defibrillator lead replaced with a different model positioned at the right ventricular apex. The patient made an uneventful recovery. The management and avoidance of delayed cardiac perforation by transvenous leads were discussed. |
7,121 | Does atrial fibrillation beget ventricular fibrillation in patients with acute myocardial infarction? | Atrial fibrillation (AF) is associated with increased mortality and a higher complication rate postmyocardial infarction (MI), but the exact mechanisms are unknown. We investigated whether AF predisposes to ventricular arrhythmia in postmyocardial infarct patients, thereby accounting for increased mortality.</AbstractText>Five hundred consecutive patients admitted to our coronary care unit with acute MI were monitored for in-hospital arrhythmias. Detailed information was also compiled on past history, co-morbidities, electrolyte disturbances, drug therapies, and ejection fraction. Mortality data were collected for an average of 5.5 years.</AbstractText>The results have shown that the incidence of ventricular fibrillation (VF) is much greater in patients presenting with AF (P=0.03) and multivariate analysis has shown that AF is independently associated with the development of VF. This association occurs principally in patients who are admitted with AF (P=0.01) rather than those who develop it during their admission, although these patients are also at mildly increased risk. The increased incidence of VF does account for increased mortality in the AF patients but does not explain all of their excess risk. There was no association between AF and ventricular tachycardia (VT); P=0.50.</AbstractText>In conclusion, AF on admission to the hospital with acute MI is associated with an increased risk of VF and subsequent mortality.</AbstractText> |
7,122 | Ablation of polymorphic ventricular tachycardias in patients with structural heart disease. | Monomorphic ventricular premature beats (VPB) originating from the Purkinje network can induce polymorphic ventricular tachycardia (PMVT) and ventricular fibrillation (VF) storm. We hereby report the results of targeted ablation to treat PMVT/VF storms initiated by monomorphic VPB in seven patients with structural heart disease and left ventricular (LV)-dysfunction (n=4 withcoronary artery disease (CAD), n=2 with chronic and remote myocarditis, n=1 after aortic valve replacement).</AbstractText>Pace-mapping and activation mapping was used to identify optimal ablation targets. Earliest activation during mapping was found midseptal of LV in three patients, midinferoseptal of LV in two patients. One patient with myocarditis showed earliest activation at free wall of right ventricle, the other one basal midseptal of LV. Local ventricular electrograms at the successful ablation sites were preceded by short, high frequency, low amplitude potentials by 22-90 ms (median 35 ms). The same local potentials were seen in sinus rhythm. Cycle lengths of VT ranged between 200 and 360 ms (median 245 ms). A median of nine radiofrequency (RF)-ablations (range 3-19) were necessary to abolish all local Purkinje potentials at the site of earliest activation. Two patients with CAD died due to refractory heart failure. The other five patients had no recurrence of PMVT and VF during follow up (median 10 months, range 1-27 months).</AbstractText>The distal Purkinje network plays an important role in triggering PMVT/VF in patients with structural heart disease. Ablation of the triggering VPB originating from the Purkinje arborization is feasible; prevents recurrence in a long-term follow up; and is potentially life saving in patients with severe LV-dysfunction after myocardial infarction, in patients after aortic valve replacement, or in patients with myocarditis particularly when medical treatment, including antiarrhythmic drugs, failed to suppress electrical storms.</AbstractText> |
7,123 | [The effects of modulation of cardiac metabolism and antioxidant state on myocardial ischemia-reperfusion injury]. | The effects of mexicor (ethylmethylhydroxypyridine succinate) at doses of 50 and 100 mg/kg on myocardial infarct size, serum levels of myocardial markers, and severity of ischemia- and reperfusion-induced arrhythmias were studied in the rat model of myocardial ischemia-reperfusion injury. It was shown that pre-ischemic intravenous infusion of mexicor at a dose of 50 mg/kg resulted in significant reduction of myocardial infarct size and troponin I level. When the dose of mexicor was increased up to 100 mg/kg the infarct-limiting effect was reversed. Both doses of mexicor tested in this study failed to protect the heart from ischemic tachyarrhythmias but decreased the occurrence of persistent reperfusion-induced ventricular fibrillation. |
7,124 | Feasibility and safety of remote-controlled magnetic navigation for ablation of atrial fibrillation. | Radiofrequency ablation for atrial fibrillation (AF) involves complex catheter manipulation resulting in prolonged procedure time and fluoroscopy exposure. Remote magnetic navigation (RMN) represents a novel approach toward improving the ability to perform complex ablation. Forty patients underwent ablation for AF, 20 using RMN (NIOBE II, Stereotaxis, Inc) with a 4-mm-tip magnetic catheter (Celsius, Biosense Webster) and 20 using a conventional 8-mm-tip bidirectional ablation catheter (Blazer, Boston Scientific). All patients underwent a combined wide area circumferential ablation and segmental pulmonary vein (PV) isolation using a circular mapping catheter and cavotricuspid isthmus ablation for right atrial flutter. The procedural end point was PV entrance block. There was no difference in atrial size, left ventricular systolic function, or type of AF between groups. PV entrance block was achieved in all patients. Mean procedure time was 279 +/- 60 minutes in the conventional group versus 209 +/- 56 minutes in the RMN group (p <0.001). Mean fluoroscopy time in the conventional group was 58.6 +/- 21 minutes versus 19.5 +/- 9.8 in the RMN group (p <0.001). At 1 year there were 15 patients in the conventional group and 16 in the RMN group free from clinical AF and off antiarrhythmic drugs (p = NS). There were 2 additional ablations performed for atypical atrial flutter in the conventional group and 3 in the RMN group (p = ns). Ablation catheter char formation was not observed. There were no procedural complications. In conclusion, radiofrequency ablation of AF performed with RMN is safe and feasible. Compared with conventional hand-navigated ablation, RMN ablation results in similar clinical outcomes with decreased fluoroscopy and procedure times. |
7,125 | Thirty-year trends (1975-2005) in the magnitude, patient characteristics, and hospital outcomes of patients with acute myocardial infarction complicated by ventricular fibrillation. | Limited contemporary data are available describing the incidence rates, hospital prognosis, and factors associated with the occurrence of ventricular fibrillation (VF) in patients hospitalized with acute myocardial infarction (AMI). The objectives of our study were to examine 3-decade-long trends (1975 to 2005) in the magnitude, predictors, and hospital case-fatality rates associated with VF in residents of a large New England metropolitan area hospitalized at all area medical centers with an uncomplicated AMI. The study population consisted of 7,472 residents of the Worcester (Massachusetts) metropolitan area hospitalized with an uncomplicated AMI in 15 annual periods from 1975 to 2005. The overall proportion of patients who developed VF was 4.2%. The incidence rates of VF remained stable from 1975 to 1995 but decreased thereafter, reaching their lowest frequency in 2005 (1.9%). Hospital case-fatality rates were significantly higher in patients with (40.9%) compared with those without (2.5%) VF. Decreases in hospital death rates over time were observed in patients with and without VF, with the decreases in death rates being greater for patients with VF. Patients who developed a Q-wave MI or a left or right bundle branch block were at particularly increased risk for developing VF. In conclusion, our results indicate that the incidence and hospital death rates associated with VF have decreased during recent years. |
7,126 | Magnitude and prognosis associated with ventricular arrhythmias in patients hospitalized with acute coronary syndromes (from the GRACE Registry). | The incidence, prognosis, and factors associated with ventricular arrhythmia (VA) in acute coronary syndrome are unknown. We sought to examine the magnitude, predictors, and outcomes of in-hospital VA in patients with acute coronary syndrome. The population comprised 52,380 patients enrolled in the Global Registry of Acute Coronary Events from 1999 to 2005. The proportion who developed VA during hospitalization was 6.9% (1.8% with ventricular tachycardia, 5.1% with ventricular fibrillation or cardiac arrest). The incidence of in-hospital VA decreased over time (8.0% in 1999, 7.0% in 2002, 5.8% in 2005, p <0.001). In-hospital case-fatality rates were higher in patients with versus those without VA (52% vs 1.6%). Several demographic and clinical variables were associated with the occurrence of VA including ST deviation, Killip class, age, initial cardiac markers, serum creatinine and heart rate, and history of selected co-morbidities. Six-month postdischarge mortality was higher in survivors of in-hospital VA versus those who did not develop VA during hospitalization (odds ratio 1.57, 95% confidence interval 1.27 to 1.95). In conclusion, development of VA during hospitalization for acute coronary syndrome was associated with higher in-hospital and 6-month mortalities. |
7,127 | Rationale, design, and baseline characteristics of a Program to Assess and Review Trending INformation and Evaluate CorRelation to Symptoms in Patients with Heart Failure (PARTNERS HF). | Heart failure (HF) is a common medical problem with significant morbidity and mortality. Recently, device-based therapy, cardiac resynchronization therapy (CRT), implantable cardioverter-defibrillators (ICDs), and combined CRT and ICD have become established therapies in patients with HF receiving standard medical therapy. Contemporary implantable devices are able to continuously monitor, store, and display long-term diagnostic information. Daily diagnostic information includes intrathoracic impedance, patient activity, hours spent in atrial tachycardia/fibrillation, ventricular rate during atrial tachycardia/fibrillation, ventricular tachyarrhythmia episodes, ICD shocks, day and night heart rate, and heart rate variability.</AbstractText>PARTNERS HF is a prospective, nonrandomized, multicenter observational study. Patient data are collected at baseline and at 3, 6, 9, and 12 months. Our objectives are to assess the relationship between the (1) diagnostic data and HF-related events, (2) diagnostic data and HF-related health care utilizations, and (3) OptiVol (Medtronic, Inc, Minneapolis, MN) fluid monitoring diagnostic data and clinically relevant pulmonary congestion events in a subset of patients. The study has enrolled 1,024 patients with a commercially available combined CRT and ICD system at 100 sites in the United States. Participants will be followed for 1 year.</AbstractText>Enrollment was completed in January 2007. Key baseline characteristics include the following: mean age of 68.4+/-10.8 years, 32% female, 13% people of color, 64% with ischemic HF, and >80% of patients reported to be on recommended HF medications at enrollment.</AbstractText>The results of PARTNERS HF could help identify device diagnostic information that may provide an early recognition of impending HF-related events.</AbstractText> |
7,128 | A computational study of mother rotor VF in the human ventricles. | Sudden cardiac death is one of the major causes of death in the industrialized world. It is most often caused by a cardiac arrhythmia called ventricular fibrillation (VF). Despite its large social and economical impact, the mechanisms for VF in the human heart yet remain to be identified. Two of the most frequently discussed mechanisms observed in experiments with animal hearts are the multiple wavelet and mother rotor hypotheses. Most recordings of VF in animal hearts are consistent with the multiple wavelet mechanism. However, in animal hearts, mother rotor fibrillation has also been observed. For both multiple wavelet and mother rotor VF, cardiac heterogeneity plays an important role. Clinical data of action potential restitution measured from the surface of human hearts have been recently published. These in vivo data show a substantial degree of spatial heterogeneity. Using these clinical restitution data, we studied the dynamics of VF in the human heart using a heterogeneous computational model of human ventricles. We hypothesized that this observed heterogeneity can serve as a substrate for mother rotor fibrillation. We found that, based on these data, mother rotor VF can occur in the human heart and that ablation of the mother rotor terminates VF. Furthermore, we found that both mother rotor and multiple wavelet VF can occur in the same heart depending on the initial conditions at the onset of VF. We studied the organization of these two types of VF in terms of filament numbers, excitation periods, and frequency domains. We conclude that mother rotor fibrillation is a possible mechanism in the human heart. |
7,129 | Treatment of atrial fibrillation. | Atrial fibrillation (AF) is the most common, sustained rhythm disturbance. The prevalence of AF is increasing as people live longer. Common conditions such as hypertension and ischaemic heart disease play an important role in the development of AF. The presence of AF is associated with increased morbidity and mortality from stroke and heart failure, particularly in patients with structural heart disease.</AbstractText>This article provides evidence-based information on the key aspects of managing AF which is based on major guidelines, landmark clinical trials and meta-analyses.</AbstractText>It is well recognized that both rate control and rhythm control are important strategies for the management of AF, but each approach should be chosen according to individual patient circumstances. A vast majority of elderly, relatively asymptomatic patients will benefit from ventricular rate control. Embolic stroke remains a major complication of AF. Yet, anticoagulation with warfarin remains underprescribed, especially in the elderly due to the presumed risk of bleeding. The technique of catheter ablation continues to improve and is generally successful in younger patients with relatively normal hearts.</AbstractText>There are clinically relevant differences among published schemes designed to stratify stroke risk in patients with AF. The CHADS2 score is currently the most simple system to give some initial estimate of stroke risk in AF patients, but could significantly underestimate this risk, particularly in those who fall in the 'intermediate' risk category.</AbstractText>Novel antiarrhythmic agents, including atrial specific agents with improved efficacy and safety profile, are currently under development. New antithrombotic agents with efficacy similar to warfarin which do not require regular INR testing appear to be promising, but there are lack of data about their long-term safety. There is increasing evidence that inflammation and fibrosis may play a major role in the initiation and maintenance of AF. Statins by means of their pleotropic effects and angiotensin-converting enzyme inhibitors and angiotensin receptor blockers by preventing atrial remodelling may prove useful in preventing the development of AF. However, there is insufficient evidence to expand the use of these agents to a wider patient population at risk of AF. It needs to be seen if strategies towards primary and secondary prevention with treatment of underlying heart disease and modification of risk factors have a larger effect than specific interventions in preventing the burden of AF in the general population.</AbstractText> |
7,130 | Chest compression quality variables influencing the temporal development of ROSC-predictors calculated from the ECG during VF. | Predictive measures that reflect the probability of return of spontaneous circulation (ROSC) if the patient is defibrillated can be calculated from the electrocardiogram during ventricular fibrillation (VF) and ventricular tachycardia (VT). It has not been studied how the quality of chest compressions affect the development of such ROSC predictors.</AbstractText>We have formulated a model for the effect of chest compressions on the ROSC predictor median-slope (MS). For untreated VF/VT MS is assumed to decay with time and increases in MS are attributed to the effect of chest compressions. The model correlates observed trends in MS with compression quality variables derived from measurements of compression depth and force recorded during out-of-hospital cardiac arrest. Among the quality variables tested were compression rate, depth, duty cycle, leaning depth, force, work and a novel quality indicator termed residual heart force. The model was first developed on an exploration dataset and thereafter validated against independent data.</AbstractText>When testing the indicators one by one, residual heart force (p<0.0001), force (p<0.0001) and work (p=0.0210) were significantly correlated to MS development. In multivariate analysis, residual heart force (p<0.0001) was the most significant indicator. Adjusting for residual heart force, there was a tendency that increased depth was associated with smaller effect of compressions (p=0.0330).</AbstractText>Using MS as an indicator of the state of the myocardium, force-based compression quality variables are better indicators of efficient CPR than compression depth. A novel indicator termed residual heart force gives the best correlation with observed trends in MS.</AbstractText> |
7,131 | Short QT syndrome. Update on a recent entity. | The short QT syndrome, a recently discovered ion channel disorder, combines shortened repolarization, a predisposition to atrial and ventricular fibrillatory arrhythmias, and a risk of sudden death. Few cases have been reported, but the prevalence may be underestimated. This syndrome might account for some cases of unexplained ventricular fibrillation in patients with otherwise healthy hearts. Patients have abnormally short QT intervals and refractory periods, and atrial/ventricular fibrillation can be triggered during investigations. Gain-of-function mutations have been detected in three genes encoding potassium channels. Treatment is based on defibrillator implantation, sometimes as a preventive measure. Quinidine may be beneficial in certain cases. |
7,132 | Defibrillation and the quality of layperson cardiopulmonary resuscitation-dispatcher assistance or training? | To examine whether basic life support-defibrillation (BLS-D) training of laypersons enhances the speed of defibrillation and the quality of cardiopulmonary resuscitation (CPR) during a simulated ventricular fibrillation scenario compared with a situation where the care provider has no previous BLS-D training but receives dispatcher assistance with the use of an automated external defibrillator (AED) and the performance of CPR.</AbstractText>Fifty-two military conscripts of the Finnish Defence Forces who without previous medical education had been tested in a simulated cardiac arrest scenario with dispatcher assistance and thereafter received a 4-h BLS-D training. Six months later they were randomly divided to form teams of two and again tested in a similar scenario but without dispatcher assistance. The time interval from collapse to first shock, hands-off time and the quality of CPR were compared between the two tests.</AbstractText>The quality of mouth-to-mouth ventilation was better after training, but there was only a minor improvement in the quality of compressions and the speed of defibrillation.</AbstractText>Training improved the quality of mouth-to-mouth ventilation performed by laypersons but had only a minor effect on defibrillation and the quality of compressions.</AbstractText> |
7,133 | Brugada syndrome unmasked by sodium channel blockade. | We report the case of a 29-year-old male suffering from recurrent syncope and palpitations. He had a structurally normal heart and his baseline electrocardiogram was normal. His electrophysiologic study revealed an inducible, nonsustained polymorphic ventricular tachycardia on programmed electrical stimulation. With the administration of intravenous Flecainide, there was typical ST-segment elevation in leads V2 and V3, indicative of the Brugada syndrome. He underwent an implantable cardioverter defibrillator implantation. The cardioverter defibrillator delivered an appropriate shock when the patient suffered ventricular fibrillation during follow-up one year later. This report illustrates the role of pharmacologic challenge in the diagnosis of the Brugada syndrome. |
7,134 | Ventricular fibrillation triggered by marijuana use in a patient with ischemic cardiomyopathy: a case report. | A 60-year-old man presented to the emergency department with a left eye orbital rupture sustained during a fall due to syncope shortly after smoking more than his usual amount of marijuana.</AbstractText>The patient reported experiencing a shock from his implantable cardioverter-defibrillator (ICD) device prior to the loss of consciousness. There was no biochemical, electrocardiographic, or clinical evidence of ischemia. ICD interrogation revealed one episode of ventricular fibrillation which was appropriately sensed and treated with a single shock of 35 Joules.</AbstractText>Although the cardiovascular effects of marijuana are usually well tolerated in young healthy users, its use may trigger life-threatening arrhythmias in patients with structural heart disease. To the best of our knowledge, this is the first report on a case of ventricular fibrillation triggered by marijuana use in a patient with an ICD.</AbstractText> |
7,135 | Anomalous coronary artery from the wrong sinus in a 15-year-old boy. | Congenital coronary artery anomalies are a well-recognized risk factor for sudden cardiac death in children as well as young adults, mostly during or immediately after intense exertion on the athletic field. Because these malformations are amenable to surgical treatment, timely identification is crucial. Unfortunately, antemortem diagnosis is notoriously difficult, partly due to the absence of abnormal test results in routine investigations. We present a 15-year-old boy who collapsed during exercise due to ventricular fibrillation. Coronary abnormalities were initially not identified, but they were clearly visualized by means of an echocardiogram and confirmed by multislice computed tomography. We would like to emphasize that echocardiography is capable of accurately identifying congenital coronary anomalies when attention is paid to the correct diagnostic hallmarks. |
7,136 | A case study in therapeutic hypothermia treatment post-cardiac arrest in a 56-year-old male. | Cellular damage related to reperfusion injury after successful resuscitation may lead to increased morbidity and mortality in survivors of cardiac arrest. Therapeutic hypothermia to decrease the effects of reperfusion injury has demonstrated improved neurologic outcomes for patients who have experienced out-of-hospital cardiac arrest due to ventricular fibrillation.</AbstractText>A 56-year-old male remained unresponsive after successful resuscitation following an out-of-hospital cardiac arrest. A repeat cardiac arrest with pulseless electrical activity occurred in the cardiac catheterization lab and required six additional minutes of resuscitation prior to restoration of cardiac rhythm and perfusion. The patient remained unresponsive after resuscitative events. Therapeutic hypothermia was initiated and maintained for 24 hours. The patient was then rewarmed, weaned off sedation and paralytics and good neurologic function demonstrated. The patient was extubated on Day 3, transferred to the telemetry unit, and was discharged home four days after admission, neurologically intact.</AbstractText>Twenty-four hours of therapeutic hypothermia for patients who remain unresponsive following successful resuscitation after experiencing out-of-hospital ventricular fibrillation is a viable option for preservation of neurological function. The National Registry of Cardiopulmonary Resuscitation (NRCPR), sponsored by the American Heart Association (AHA), was developed with a goal to enhance patient safety and reduce patient disability and death through "providing an evidence-based, quality improvement program of patient safety, medical emergency team response, effective resuscitation and post-emergency care" to patients that have experienced cardiopulmonary events. NRCPR reports from 2007 include data from 127 participating organizations with information submitted on 19,555 in-patients who experienced 22,919 cardiopulmonary arrest (CPA) events. Of all of the arrests that occurred, 78.3 percent of patients involved did not survive the event. For those who did survive the event, an additional 35.2 percent died afterward, either via removal of life-support or natural death in the presence of do-not-resuscitate (DNR) directives. The remaining survivors (21.3 percent) were discharged to a variety of environments with home being the most common (48.5 percent), followed by skilled nursing facilities (19.2 percent), rehabilitation centers (12.4 percent), other acute care hospitals (11.8 percent) and hospice care (4.7 percent). From this information, it is apparent that continued research and improvements are essential to provide patients successful resuscitation and to decrease the complications that occur afterward. We present the case of a patient who remained comatose after return of spontaneous circulation (ROSC) following out-of-hospital ventricular fibrillation (VF) cardiac arrest in whom therapeutic hypothermia treatment was utilized with a positive neurological outcome.</AbstractText> |
7,137 | [The progress of therapeutic hypothermia for patients with comatose survivors of out-of-hospital cardiac arrest this century]. | Two randomized clinical trials were reported using mild therapeutic hypothermia following cardiac arrest in the 2002. One is the multicenter randomized clinical trial projected by The Hypothermia after Cardiac Arrest Study Group. The other one was performed by four centers in Australia. Two trials significantly showed better outcome in the hypothermia group compared with the normothermia group. There were some differences between Europe study and Australia study, although their outcome was doing very well. We will discuss cooling techniques (blanket or ice pack or cold saline intravenously), selection of patients (ventricular fibrillation or pulseless electrical activity or asystole), timing of cooling (as possible as earlier or within 3 hours or 6 hours) and monitoring in the hypothermia group in future. In addition, clinicians including cardiologists, intensivists, emergency physicians and neurologists, should work together to practice protocols for mild hypothermia treatment. |
7,138 | The potential mechanisms of reduced incidence of ventricular fibrillation as the presenting rhythm in sudden cardiac arrest. | In the last two decades, the incidence of ventricular fibrillation has significantly decreased as the presenting rhythm in sudden cardiac arrest. We hypothesized that beta-adrenergic receptor blocker (beta-blocker) and angiotensin converting enzyme inhibitor, which were commonly used in the primary and secondary prevention strategies recommended by the American Heart Association during the same decades, decrease the duration of ventricular fibrillation after onset of cardiac arrest.</AbstractText>Randomized prospective animal study.</AbstractText>University affiliated research laboratory.</AbstractText>Male Sprague-Dawley rats.</AbstractText>Male Sprague-Dawley rats, weighing 450-550 g were administered either beta-blocker, propranolol, angiotensin converting enzyme inhibitor, captopril, or placebo for 2 wks. In the phase 1 study, ventricular fibrillation was induced by ligation of the proximal left coronary artery. In the phase 2 study, the experiments were repeated with the measurements of duration of monophasic action potential and threshold of ventricular fibrillation. Both propranolol and captopril significantly decreased the duration of ventricular fibrillation in comparison with controls (p < 0.05). In the phase 2 study, both propranolol and captopril significantly increased the threshold of ventricular fibrillation (p < 0.05) and monophasic action potential (p < 0.05).</AbstractText>Ventricular fibrillation remains as the leading causal rhythm of sudden cardiac arrest. However, the drugs widely used in primary and secondary coronary artery disease prevention strategies shortened the duration of ventricular fibrillation. This may result in the reduced incidence of ventricular fibrillation as the presenting rhythm in sudden cardiac arrest. Increased threshold of ventricular fibrillation and monophasic action potential after administration of those agents may be the potential mechanisms of reduced duration of ventricular fibrillation.</AbstractText> |
7,139 | Alternative technique for implanting an implantable cardioverter defibrillator in infants. | We applied a new implanting technique for an implantable cardioverter defibrillator (ICD) in a 4-month-old girl with repeated ventricular fibrillation (Vf) due to long QT syndrome. This technique consisted of placement of an oval patch lead on the outer surface of the pericardium in the left pleural cavity. This was useful in preventing the complications of the conventional epicardial patch leads (ie, crinkling of the lead and constrictive pericarditis). This patch should be contemplated as an alternative option for implanting ICD in infants. |
7,140 | Video-assisted thoracoscopic cardiac denervation: a potential novel therapeutic option for children with intractable ventricular arrhythmias. | Left cardiac sympathetic denervation is one of the therapeutic modalities used in the management of patients with medically refractory long QT syndrome. Traditionally, a thoracotomy or cervical incision has been used as the standard surgical approach for performing left cardiac sympathetic denervation. Video-assisted thoracoscopic surgery allows a minimally invasive technique. There is only one published series on the use of video-assisted thoracoscopic surgery for left cardiac sympathetic denervation in patients with long QT syndrome.</AbstractText>We performed a retrospective clinical review of pertinent medical records and report a series including 9 pediatric patients (4 long QT syndrome, 4 catecholaminergic polymorphic ventricular tachycardia, and 1 idiopathic ventricular tachycardia) who underwent a left cardiac sympathetic denervation by means of video-assisted thoracoscopic surgery.</AbstractText>There were no severe complications, and 6 of 7 symptomatic patients with available follow-up experienced marked improvement in the first month after sympathectomy.</AbstractText>This minimally invasive procedure provides a safe novel therapeutic option for children with drug-refractory catecholaminergic polymorphic ventricular tachycardia and other catecholamine-triggered arrhythmias.</AbstractText> |
7,141 | Intermediate to long-term results of radiofrequency modified Maze procedure as an adjunct to open-heart surgery. | Of patients scheduled for elective open heart surgery, a substantial number of patients have preoperative atrial fibrillation (AF). The cut-and-sew Maze procedure and variant Maze procedures abolish AF in 45% to 95% during short- to intermediate-term follow-up. Limited data are available about maintenance of sinus rhythm during intermediate- to long-term follow-up. The objective of the present study was to assess the association between postoperative rhythm and mortality and stroke.</AbstractText>From November 1995 to November 2003, 258 patients with structural heart disease and permanent AF with a duration of longer than 12 months were scheduled for elective cardiac surgery and included in a registry. They underwent a radiofrequency modified Maze procedure as an adjunct to the open heart operation. Patients were followed in the outpatient clinic, and follow-up data were obtained from medical correspondence of attending physicians. For this paper, follow-up ended November 2006; however, patients are being followed in an ongoing registry.</AbstractText>Two hundred fifty-eight patients (mean age, 68.1 +/- 9.5 years) with permanent AF underwent cardiac surgical procedures and concomitant radiofrequency Maze surgery; 213 patients (82.5%) underwent more than one procedure. Mean duration of permanent AF was 66.6 +/- 69.8 months (range, 16 to 96). Preoperatively, 82.9% of patients were in New York Heart Association class III. In-hospital mortality was 3.9% (10 patients), and during a mean follow-up of 43.7 +/- 25.9 months (range, 27 to 114), 73 patients (28.3%) died. Left ventricular ejection fraction was normal in 44.6%, moderately decreased in 42.5%, and poor in 12.9% of patients. Sustained sinus rhythm, including atrial rhythm or an atrial-based paced rhythm was present in 69% of patients at 1 year, in 56% at 3 years, in 52% at 5 years, and in 57% of patients at the latest follow-up. Antiarrhythmic drugs were used by 64% of survivors who were free of atrial fibrillation. Oral anticoagulation therapy was taken by 99% of patients. Stroke was reported in 4 patients (1.6%).</AbstractText>The RF modified Maze procedure abolishes AF in the majority of patients with structural heart disease and longstanding permanent AF. Postoperative rhythm was not predictive of all-cause mortality, cardiac mortality, and stroke, neither in the whole group nor in the subgroups defined by preoperative left ventricular ejection fraction and New York Heart Association class. The stroke rate was very low in this group with longstanding AF.</AbstractText> |
7,142 | [The use of a morphohistochemical method for the diagnosis of heart contusion]. | This morphohistochemical study was carried out using myocardial tissue samples obtained from subjects with heart contusion. The aim of the study was to elucidate the cause of ventricular fibrillation associated with alternative myocardial insufficiency. It is concluded that changes of Ca2+ ion content in the myocardial tissue may be one of the factors contributing to the development of ventricular fibrillation. |
7,143 | The effect of rapid blood pressure control on P-wave dispersion in hypertensive urgency. | A sharp increase in blood pressure, increase in atrial pressure and atrial strain, left ventricular diastolic dysfunction, and left ventricular hypertrophy (LVH) lead to heterogeneity and instability in atrial conduction. The resulting physiopathological situation may elevate maximum Pwave duration (P(max)) and P-wave dispersion (PWD) in electrocardiography. The objective of our study was to explore the effect of the sudden change in atrial hemodynamics on P(max) and PWD, which may indicate the risk of atrial fibrillation (AF) development in hypertensive urgency.</AbstractText>The study included patients diagnosed as hypertensive urgency (systolic blood pressure > or =180 mmHg, diastolic blood pressure > or =110 mmHg). Nitroprusside was started at a dose of 0.2 microg/kg/min, and the ensuing dose was arranged according to blood pressure. Echocardiography and electrocardiography were used to noninvasively measure changes in diastolic function and PWD and P(max), respectively.</AbstractText>The study enrolled 102 patients (mean age 57.9+/-11.6 years; 32 [31.4%] males, and 70 [68.6%] females). P(max) decreased from 99.9+/-11.1 msec (95% confidence intervals [CI] 97.7, 102) to 88.5+/-9.3 msec (95% CI 86.6, 90.3) (P<0.001), while PWD decreased from 60.1+/-7.4 msec (95% CI 58.7, 61.6) to 43.9+/-6.7 msec (95% CI 42.5, 45.2) (P<0.001). In addition, most patients had LVH and diastolic dysfunction. After nitroprusside treatment improvements in indicators of diastolic functions such as E/A ratio, deceleration time, and isovolumetric relaxation time were observed.</AbstractText>The change observed in P(max) and PWD in hypertensive urgency may be associated with the rapid change in blood pressure and atrial strain, sympathetic nervous system activation, relative myocardial ischemia, and left ventricular diastolic dysfunction. Rapid regulation of blood pressure with nitroprusside brought about a marked decrease in P(max) and PWD in our patients. This improvement was interpreted as atrial conduction acquiring a stable and homogeneous character, which may reduce the risk of AF development in hypertensive urgency.</AbstractText> |
7,144 | Recent advances in metabolic syndrome and cardiovascular disease. | Metabolic syndrome is defined as an association of central obesity and several other cardiometabolic risk factors. Dysfunctional visceral adipose tissue and inflammatory status appear to be involved in its genesis. New definitions have decreased the threshold for glycaemia and one has lowered the threshold for waist circumference, leading to an increase in the prevalence of metabolic syndrome. However, the impact on mortality with these new definitions is lower than with the National Cholesterol Education Program-Adult Treatment Panel III 2001 definition. An increase in waist circumference, along with increased glycaemia, triglycerides and/or blood pressure is more highly associated with an increased risk of mortality than are other associations, while a decrease in high density lipoprotein cholesterol increases risk of coronary heart disease. The risk of sudden death and stroke is particularly notable with metabolic syndrome. Metabolic syndrome is associated with an increase in heart rate, pulse pressure, arterial stiffness and left ventricular hypertrophy, impairment of diastolic function, enlargement of the left atrium and atrial fibrillation. In the 2007 European recommendations for the management of high blood pressure, metabolic syndrome is now taken into consideration for both risk stratification and in selecting the optimal therapeutic strategy for arterial hypertension. |
7,145 | Echocardiographic speckle tracking radial strain imaging to assess ventricular dyssynchrony in a pacing model of resynchronization therapy. | Speckle tracking imaging is a promising new echocardiographic method to assess left ventricular (LV) mechanical dyssynchrony. Our aim was to assess a new speckle tracking regional strain algorithm by comparison with angle-corrected tissue Doppler (TD) in an animal model of left bundle branch block and cardiac resynchronization therapy.</AbstractText>Ten open-chest dogs had routine gray-scale and TD images of the mid-LV short-axis plane. Electrical activation was altered by pacing from right ventricular, LV free wall, and biventricular sites to create various degrees of mechanical dyssynchrony and alter regional function. Segmental time to peak strain, peak strain, and frame-by-frame strain were measured by angle-corrected TD, TD M-mode, and speckle tracking on the same digital cineloop. Of 240 possible paired TD and speckle tracking segments, data were available for 222 segments (93%); images with catheter artifacts were prospectively excluded. Comparative overall time to peak strain by each method correlated well: r = 0.96, bias = -6 +/- 20 ms. Of 80 possible paired M-mode TD and speckle tracking segments, strain data were available for 76 segments (95%). Comparative overall time to peak strain, peak strain, and frame-by-frame strain analysis in 1012 frames by each method correlated well: r = 0.98, bias of 1 +/- 14 ms; r = 0.82, bias of 3% +/- 7%; and r = 0.91, bias of 0% +/- 6%, respectively.</AbstractText>Regional strain analysis using echocardiographic speckle tracking radial strain strongly correlated with strain by angle-corrected TD imaging in an animal model of dyssynchrony. Speckle tracking radial strain has potential for clinical applications.</AbstractText> |
7,146 | Prevalence and potential mechanisms of sustained ventricular arrhythmias during dobutamine stress echocardiography: a literature review. | Sustained ventricular tachycardia during dobutamine stress echocardiography is a rare complication of dobutamine stress echocardiography. It may be related to reduced left ventricular function and prior myocardial infarction but cannot be used as a sensitive or specific sign for myocardial ischemia. The clinical significance of dobutamine stress echocardiography-induced sustained ventricular tachycardia is uncertain, and this condition probably does not represent an adverse prognostic sign. |
7,147 | Ventricular arrhythmogenesis: insights from murine models. | Ventricular arrhythmias are the key underlying cause of sudden cardiac death, a common cause of mortality and a significant public health burden. Insights into the electrophysiological basis of such phenomena have been obtained using a wide range of recording techniques and a diversity of experimental models. As in other fields of biology, the murine system presents both a wealth of opportunities and important challenges when employed to model the human case. This article begins by reviewing the extent to which the murine heart is representative of that of the human. It then presents a novel physiological classification of mechanisms of arrhythmogenesis, critically assessing the extent to which the study of murine hearts has offered worthwhile insights. |
7,148 | [The incidence and predictors of atrial fibrillation in hypertrophic cardiomyopathy]. | To observe the incidence and predictors of atrial fibrillation in hypertrophic cardiomyopathy (HCM).</AbstractText>612 HCM patients were analyzed prospectively from July 1990 to November 2007. The age, sex, height, weight, medical history, main symptoms and incidence of atrial fibrillation were recorded.</AbstractText>The patients' mean age was (47.8 +/- 14.9). 414 patients (67.6%) were male. 377 patients (61.6%) had left ventricular outflow truct obstruction. 94 patients (15.4%) and atrial fibrillation. 43 patients (6.0%) had sustained and 51 patients (9.4%) had paroxysmal. The patients with atrial fibrillation were older in age and were predominantly female. Their medical history were longer, left atrial diameter (LAD) longer and plasma B-type natriuretic peptide (BNP) higher. logistic regression analysis indicated that the medical history (P = 0.012), LAD (P = 0.0001) and BNP (P = 0.017) were the independent predictors of atrial fibrillation in HCM. Atrial fibrillation was accompanied by a decrease in functional status and an increase in risk of stroke.</AbstractText>The incidence of atrial fibrillation in HCM was high. The medical history, LAD and BNP were the independent predictors of its occurrence.</AbstractText> |
7,149 | The A That Did Not Fib:Two Roads Both Traveled By. | <b>Case:</b> A 64-year-old woman presented with palpitations. Her 24-hour Holter monitor revealed runs of presumed atrial fibrillation (AF). The patient was referred for EP study and AF ablation. <b>EPS:</b> At EPS, an anterograde A-H jump was noted. Spontaneous bursts of tachycardia were seen, consisting of sinus atrial beats with dual ventricular responses, each preceded by a His deflection. There was no atrial fibrillation during the study. Radiofrequency ablation of the slow AV node pathway was performed. There were no inducible tachycardias and no A-H jump following the ablation. The patient had no recurrence post-procedure. <b>Discussion:</b> This case presents a rare example of simultaneous dual anterograde AV-nodal conduction. The conditions leading to this phenomenon include dual AVN pathways, markedly slowed conduction in the slow pathway, and lack of retrograde conduction up either pathway such that reentry was impossible. An irregular, narrow-complex tachycardia resulted, initially interpreted as AF. Slow-pathway ablation was curative. |
7,150 | Pharmacotherapy for atrial fibrillation in elderly hospitalized patients with comorbid congestive heart failure in australia: A retrospective study. | Despite the proven effectiveness of antiplatelet and anticoagulation treatment for atrial fibrillation (AF), their use has been suboptimal in practice, particularly in rural areas of Australia.</AbstractText>The aim of this study was to describe medication use in the management of AF in elderly hospitalized patients with comorbid congestive heart failure (CHF).</AbstractText>The hospital records of patients with a diagnosis of AF and CHF were reviewed in a rural Australian medical center. All the patients were hospitalized because of significant systolic ventricular dysfunction. The collected data included age, sex, weight, presenting symptoms of AF, and principle diagnosis on admission; medical history; and history of smoking and alcohol consumption. Electrocardiogram before hospital discharge was also retrieved from patient's medical records and was analyzed by the investigators. Cardiovascular and noncardiovascular drugs administered during the hospital stay and at discharge were also documented. Comparison of antiarrhythmic and anticoagulant drugs was made between patients who had AF while hospitalized and those who had a history of AF but were in sinus rhythm while hospitalized. When patients had ≥2 moderate risk factors (eg, age ≥75 years, hypertension, CHF, left ventricular ejection fraction ≤35%, diabetes mellitus) or ≥1 high risk factor (eg, previous stroke, transient ischemic attack or embolism, mitral valve stenosis, or prosthetic heart valve), they were defined as being eligible for anticoagulation treatment.</AbstractText>One hundred forty patients (74 men, 66 women; mean [SD] age, 77.1 [6.9] years; all were white) had a diagnosis of AF and were selected for the study. Of these, 92 patients (65.7%) (47 women, 45 men; mean [SD] age, 77.4 [9-2] years) had continuous AF and 48 patients (34.3%) (29 men, 19 women; mean [SD] age, 76.3 [12.4] years) had a history of AF but were in sinus rhythm at admission and discharge. The most commonly used antiarrhythmic drug was digoxin, which was prescribed significantly more frequently in the AF group than in the history of AF group (50 (54.3%] vs 14 [29.2%]; P < 0.01). Amiodarone was prescribed significantly less frequently in the continuous AF group than in the group with a history of AF (7 [7.6%] vs 19 [39-6%]; P < 0.01). There was no significant between-group difference in the use of β-blockers (26 [28.3%] vs 19 [39-6%]), verapamil/diltiazem (9 [9-8%] vs 3 [6.3%]), or Sotalol (2 [2.2%] vs 4 [8.3%]). The mean (SD) resting heart rate for the 140 study patients was 91 (27) bpm. The mean resting heart rate for the patients with AF was significantly higher at admission than at discharge (97 [28] vs 79 [19] bpm; P < 0.01). Of the 110 patients who were eligible for anticoagulation treatment, 64 (58.2%) were prescribed warfarin at discharge. Eligible patients not receiving oral warfarin were significantly older than those who did receive warfarin (79-7 [9-0] vs 75.8 [9.0] years; P = 0.02).</AbstractText>In these elderly hospitalized Australian patients with AF and CHF, digoxin, β-blockers, and amiodarone were the most commonly used antiarrhythmic drugs. Anticoagulation treatment was prescribed in ~60% of these patients.</AbstractText> |
7,151 | Innovation focus: the patient with arrhythmia. | Great strides have been made over the last two decades in the management of patients with rhythm disorders. Despite this, however, the remaining critical problems of stroke related to atrial fibrillation or as a result of radiofrequency ablation require innovative solutions to fully realize the potential of these recent advances. Similarly, implanted cardiac devices have revolutionized the care of patients with bradyrhythmias and tachyarrhythmias. Dyssynchronus ventricular pacing associated with present devices; however, results in heart failure, tricuspid regurgitation, and inappropriate device therapy once again create a demand for creative solutions. While not technically an arrhythmia, epilepsy management today is riddled with many of the problems that plagued cardiac arrhythmia management previously, and thus an appreciation of the similarities in requirement for investigative solutions may yield groundbreaking solutions. In this paper, we describe some novel methods to reduce complications associated with rhythm disorders and their treatment and apply the lessons learned from cardiovascular arrhythmia management to the brain. These include: a method to reduce coagulum formation and thus subsequent thromboembolism with indwelling catheters specifically during radiofrequency ablation procedures; a technique to ligate the left atrial appendage through percutaneous subxiphoid pericardial access; development and testing of a novel intramyocardial pace-sense lead, particularly used in a unique anatomic location (the atrioventricular septum) to allow pacing the ventricles in a relatively synchronous manner without crossing the tricuspid valve or entering the coronary sinus; finally, novel modifications of the cardiovascular mapping and ablation techniques used for the management of the central nervous system disorders primarily via the venous drainage of the brain. Innovative and potential solutions to treat the patient with arrhythmia are presented. |
7,152 | Twisting until it breaks: a rare cause of ICD lead failure. | We describe a rare case of Twiddler's syndrome that resulted in a complex ICD lead fracture involving both the insulation and the conductor. The conductor fracture resulted in noise artefact that was interpreted by the device as ventricular fibrillation, but the patient had not received any shocks because the "episodes" were non-sustained. The patient did not have traditional risk factors for Twiddler's syndrome. |
7,153 | Natriuretic peptides in patients with atrial fibrillation. | The aim of the study was to evaluate plasma natriuretic peptides (NPs): atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations in patients with paroxysmal, persistent and permanent atrial fibrillation (AF).</AbstractText>The study groups consisted of 23 patients with paroxysmal AF, 42 patients with permanent AF and 77 patients with persistent AF with normal left ventricular function. The mean ANP level was increased in AF patients in the paroxysmal, persistent and permanent groups: 249 +/- 88.3 pg/mL; 258 +/- 89.7 pg/mL; 208 +/- 76.7 pg/mL, respectively, vs. 67 +/- 21.2 pg/mL in the control subjects (p < 0.001). The mean BNP level was increased in AF patients in the paroxysmal, persistent and permanent groups: 99.6 +/- 29.8 pg/mL; 82.3 +/- 33 pg/mL; 95.6 +/- 46.4 pg/mL, respectively, vs. 37.5 +/- 13 pg/mL in the control group. Multivariate logistic regression analysis revealed a positive correlation between ANP levels, maximal left atrial volume, heart rate and New York Heart Association (NYHA) classification, in the persistent AF patients. A positive correlation between plasma BNP levels and heart failure stage according to NYHA classification in this group was found. Baseline ANP concentrations were positively correlated with baseline BNP concentrations in AF patients.</AbstractText>Plasma NPs levels are increased in patients with paroxysmal, persistent and permanent AF and normal left ventricle function, and positively correlated with left atrial volume, heart rate and heart failure stage according to NYHA classification. Neurohormonal assessment does not distinguish the type of arrhythmia.</AbstractText> |
7,154 | Increased augmentation index of the radial pressure waveform in patients with paroxysmal atrial fibrillation. | The augmentation index, a marker of wave reflection, has been reported to reflect vascular properties and to determine left ventricular (LV) characteristics. We investigated the relationship between the augmentation index and paroxysmal atrial fibrillation (AF).</AbstractText>A total of 244 outpatients (122 patients with paroxysmal AF and 122 age-, and gender-matched controls without paroxysmal AF) were examined during sinus rhythm. The augmentation index was calculated from the radial arterial waveform using applanation tonometry methods.</AbstractText>After adjusting for age, gender, heart rate, and medications, the augmentation index was significantly higher in patients with paroxysmal AF than in subjects without paroxysmal AF (means +/- SE: 88.9 +/- 1.0 and 81.8 +/- 1.0%, respectively; p < 0.001). In all subjects, an increase in the augmentation index was significantly correlated with LV hypertrophy and left atrial enlargement. Multiple logistic analysis revealed that an increase in the augmentation index was significantly related with paroxysmal AF, and the adjusted odds ratio of paroxysmal AF was approximately 1.8 for each 10% augmentation index increase (p < 0.01).</AbstractText>An increase in the augmentation index was independently associated with paroxysmal AF. This result suggests that enhanced wave reflection may be related to the development of AF.</AbstractText>Copyright 2008 S. Karger AG, Basel.</CopyrightInformation> |
7,155 | Model systems for the discovery and development of antiarrhythmic drugs. | Cardiovascular diseases are the leading cause of mortality worldwide and about 25% of cardiovascular deaths are due to disturbances in cardiac rhythm or "arrhythmias". Arrhythmias were traditionally treated with antiarrhythmic drugs, but increasing awareness of the risks of presently available antiarrhythmic agents has greatly limited their usefulness. Most common treatment algorithms still involve small molecule drugs, and antiarrhythmic agents with improved efficacy and safety are sorely needed. This paper reviews the model systems that are available for discovery and development of new antiarrhythmic drugs. We begin with a presentation of screening methods used to identify specific channel-interacting agents, with a particular emphasis on high-throughput screens. Traditional manual electrophysiological methods, automated electrophysiology, fluorescent dye methods, flux assays and radioligand binding assays are reviewed. We then discuss a variety of relevant arrhythmia models. Two models are widely used in testing for arrhythmogenic actions related to excess action potential prolongation, an important potential adverse effect of chemical entities affecting cardiac rhythm: the methoxamine-sensitized rabbit and the dog with chronic atrioventricular block. We then go on to review models used to assess potential antiarrhythmic actions. For ventricular arrhythmias, chemical induction methods, cardiac or neural electrical stimulation, ischaemic heart models and models of cardiac channelopathies can be used to identify effective antiarrhythmic agents. For atrial arrhythmias, potentially useful models include vagally-maintained atrial fibrillation, acute asphyxia with atrial burst-pacing, sterile pericarditis, Y-shaped atria surgical incisions, chronic atrial dilation models, atrial electrical remodelling due to sustained atrial tachycardia, heart failure-related atrial remodelling, and acute atrial ischaemia. It is hoped that the new technologies now available and the recently-developed models for arrhythmia-response assessment will permit the introduction of newer and more effective antiarrhythmic therapies in the near future. |
7,156 | Usefulness of rate regulation through continuous ventricular pacing in patients with drug-controlled slower atrial fibrillation and normal or depressed left ventricular systolic function. | We studied 33 clinically stable patients with permanent atrial fibrillation (AF), implanted with a ventricular demand rate-responsive (VVIR) pacemaker or an automatic defibrillator, in order to evaluate whether continuous right ventricular apex pacing (VP) conferring rate regulation may be advantageous when compared with slower drug-controlled AF. Devices were chronically programmed at ventricular backup pacing. Patients were divided in two groups according to their normal (n = 17) or depressed (n = 16) left ventricular systolic function (LVSF). Ventricular function was studied by using tissue Doppler and color M-mode and echocardiography, as well as B-type natriuretic peptide (BNP) measurements. Baseline data during AF were compared to corresponding measurements following a 1-month pacing period after the devices were programmed at a base rate of 70 beats/min. In both groups, VP worsened some indexes of left and right ventricular function (P < 0.05) without significantly affecting cardiac output, left ventricular filling pressures and BNP (P = not significant). We conclude that VP should not be considered advantageous compared to slower AF. |
7,157 | Ventricular arrhythmias originating from the epicardial ventricular outflow tract complicated with peripartum cardiomyopathy. | We report two cases undergoing electrophysiological studies for ventricular arrhythmias (VAs) associated with peripartum cardiomyopathy. Those two cases demonstrated that subsequent pregnancies might result in deterioration of VAs even though they exhibit no symptoms of heart failure. Those findings may clinically impact the decision making when women with a history of peripartum cardiomyopathy desire to become pregnant again. The VA foci in both cases were determined or suggested to be in the epicardium of the ventricular outflow tract from the results of the catheter ablation and electrophysiological study. Therefore, catheter ablation of those VAs may be feasible but challenging. |
7,158 | Effect of cardiac resynchronization therapy on conversion of persistent atrial fibrillation to sinus rhythm. | Spontaneous conversion of persistent atrial fibrillation to sinus rhythm (SR) has anecdotally been reported following cardiac resynchronisation therapy.</AbstractText>This monocenter observational study was designed to estimate the incidence of spontaneous conversion of persistent atrial fibrillation to SR in consecutive patients implanted with a cardiac resynchronisation device.</AbstractText>A total of 46 patients with persistent atrial fibrillation (> or =4 weeks pre-implant), left bundle branch block (QRS > 130 ms), left ventricular ejection fraction <0.35 and NYHA III or IV heart failure were implanted with a cardiac resynchronisation pacemaker or defibrillator and followed for at least 6 months between 6/2000 to 12/2006. During 22 +/- 9 (7-34) months of follow-up, eight out of 46 patients (17%) converted to SR. Spontaneous conversion was encountered in seven cases, whereas one patient converted due to an ICD shock delivered for ventricular tachycardia; in the latter patient, previous ICD shocks had not converted atrial fibrillation. The time interval from device implantation to conversion was 12 +/- 11 (3-31) months. In patients converting to SR, the duration of atrial fibrillation before device implantation was significantly shorter than in patients remaining in atrial fibrillation (15 +/- 13 vs. 53 +/- 58 months, P = 0.001). Echocardiographic parameters such as left ventricular ejection fraction, left ventricular end-diastolic diameter, left atrial diameter did not differ significantly between converting and non-converting patients. However, patients converting to SR showed a significant reduction in systolic pulmonary artery pressure on CRT vs. before CRT (45 +/- 13 vs. 29 +/- 5 mmHg, P = 0.008).</AbstractText>This pilot study suggests that CRT favors spontaneous conversion of persistent AF to SR in a minority of patients. If confirmed by larger clinical studies, atrial lead implantation would be encouraged in these patients, in order to provide AV synchronous pacing in case of spontaneous conversion or successful cardioversion to SR on cardiac resynchronisation therapy.</AbstractText> |
7,159 | Ivabradine induces an increase in ventricular fibrillation threshold during acute myocardial ischemia: an experimental study. | Tachycardia often facilitates ischemic ventricular fibrillation (VF).</AbstractText>This study assessed the impact of ivabradine (IVA), a selective inhibitor of the cardiac pacemaker If current, on ventricular fibrillation threshold (VFT) during acute myocardial ischemia.</AbstractText>The experiments were conducted on a total of 54 domestic pigs. Myocardial ischemia was induced in anesthetized pigs by total 1-minute coronary occlusion at baseline and then on 2 occasions after intravenous administration of saline or 0.5 mg/kg of IVA. VF was triggered by electrical stimuli of increasing intensity at a fixed rate. Heart rate (HR), VFT, monophasic action potential duration, and peak of the time derivative of left ventricular pressure (LV dP/dt max) were monitored on each occasion. The activity of mitochondrial succinodehydrogenase was measured on heart sections.</AbstractText>Compared with controls, IVA induced a 31% reduction in HR, a 2.9-fold increase in VFT, and prevented ischemia-induced monophasic action potential duration shortening (+1 +/- 12 vs. -14 +/- 11 milliseconds) without affecting peak LV dP/dt. This beneficial effect on VFT was mainly due to HR reduction and was accompanied by a significant reduction in the hypoxic area (26% +/- 1% vs. 38% +/- 1%, P < 0.0001).</AbstractText>HR reduction and the decrease in myocardial damage induced by IVA protected against primary ischemic VF without altering myocardial contractility.</AbstractText> |
7,160 | Echocardiographic profile of peripartum cardiomyopathy in a tertiary care hospital in sokoto, Nigeria. | The diagnosis of peripartum cardiomyopathy in Nigeria has mostly been based on clinical criteria. Echocardiographic data are rare, even though echocardiography is useful in distinguishing this condition from others which mimic it. This is an effort to fulfill the need for such data.</AbstractText>A cross-sectional analysis of the echocardiographic data of 65 patients with peripartum cardiomyopathy was carried out. The patients were recruited prospectively for the study. The incidence rate was 1 per 102 deliveries, and the patients were predominantly (84.6%) of the Hausa and Fulani ethnic groups. There were 20 (30.8%) primiparous and 45 (69.2%) multiparous women aged 28.2 +/- 8.1 years (range: 15-45 years). Transient hypertension occurred in 18 (27.7%) patients. Customary puerperal practice was observed in 53 (81.5%). The complications included pericardial effusion (13.5%), intracardiac thrombosis (12.3%) and atrial fibrillation (3.1%). The occurrence rate was 1.5% each for stroke, pulmonary embolism and acute lower extremity arterial occlusion. The mean cardiothoracic index, left ventricular end diastolic dimension and ejection fraction were 61.4 +/- 12.0%, 6.3 +/- 1 cm and 27.4 +/- 8.2%, respectively. Twenty-seven (41.5%) patients had severe left ventricular dysfunction characterized by a left ventricular end diastolic dimension greater than 6 cm and fractional shortening less than 20%. The cardiothoracic index correlated with the left ventricular ejection fraction (r = 0.4;p = 0.03) and fractional shortening )r = 0.3; p = 0.01). The duration of salt consumption correlated with the left ventricular end diastolic dimension (r = 0.3, p = 0.01) and cardiothoracic index (r = 0.2; p = 0.04). Parity also correlated with the left ventricular end diastolic dimension (r = 0.3, p = 0.04). The mortality rate was 12.3%. Compared to the survivors, the deceased had a significantly lower ejection fraction (25.7 +/- 7.4% vs 31.4 +/- 7.7%, p = 0.03), lower diastolic pressure (67.5 +/- 10.4 vs 83.4 +/- 19.4; p = 0.04) and higher cardiothoracic index (70.2 +/- 14.4% vs 60.9 +/- 5.5%; p = 0.07) at baseline.</AbstractText>In addition to its diagnostic and prognostic usefulness, echocardiography may serve as an effective indicator in the study of the role of customary puerperal practice in the pathogenesis of peripartum cardiomyopathy in certain populations.</AbstractText> |
7,161 | Cigarette smoking and risk of atrial fibrillation: the Rotterdam Study. | Cigarette smoking is an important risk factor for cardiovascular disease, but it is unknown whether it also contributes to the risk of atrial fibrillation.</AbstractText>The study is part of the Rotterdam Study, a population-based cohort study among subjects aged > or =55 years. The association between cigarette smoking and the risk of atrial fibrillation was examined in 5,668 subjects without atrial fibrillation at baseline. During a median follow-up of 7.2 years, 371 cases of atrial fibrillation were identified. Relative risks (RR) were calculated with 95% CIs using the Cox proportional hazards model, adjusted for age, gender, body mass index, hypertension, systolic blood pressure, serum cholesterol level, diabetes mellitus, left ventricular hypertrophy on the electrocardiogram, prevalent and incident myocardial infarction, prevalent heart failure, and the use of pulmonary medication. After multivariate adjustment, current smokers and former smokers had increased risks of atrial fibrillation as compared to never smokers (RR 1.51, 95% CI 1.07-2.12; and RR 1.49, 95% CI 1.14-1.97, respectively). No differences were found between men and women.</AbstractText>The results of this prospective, population-based study show that current and former smoking of cigarettes are associated with increased risk of atrial fibrillation.</AbstractText> |
7,162 | Predominance of heart failure in the Heart of Soweto Study cohort: emerging challenges for urban African communities. | There is a paucity of data to describe the clinical characteristics of heart failure (HF) in urban African communities in epidemiological transition.</AbstractText>Chris Hani Baragwanath Hospital services the 1.1 million black African community of Soweto, South Africa. Of 1,960 cases of HF and related cardiomyopathies in 2006, we prospectively collected detailed demographic and clinical data from all 844 de novo presentations (43%). Mean age was 55 +/- 16 years, and women (479 [57%]) and black Africans (739 [88%]) predominated. Most (761 [90%]) had > or =1 cardiovascular risk. Mean left ventricular ejection fraction was 45 +/- 18%. Overall, 180 patients (23%) had isolated diastolic dysfunction, 234 (28%) tricuspid regurgitation, 121 (14%) isolated right HF, and 100 (12%) mitral regurgitation. The most common diagnoses were hypertensive HF (281 [33%]), idiopathic dilated cardiomyopathy (237 [28%]), and, surprisingly, right HF (225 [27%]). Black Africans had less ischemic cardiomyopathy (adjusted odds ratio, 0.12; 95% CI, 0.07 to 0.20) but more idiopathic and other causes of cardiomyopathy (adjusted odds ratio, 4.80; 95% CI, 2.57 to 8.93). Concurrent renal dysfunction, anemia, and atrial fibrillation were found in 172 (25%), 72 (10%), and 53 (6.3%) cases, respectively.</AbstractText>These contemporary data highlight the multiple challenges of preventing and managing an increasing and complex burden of HF in urban Africa. In addition to tackling antecedent hypertension, a predominance of young women and a large component of right HF predicate the development of tailored therapeutic strategies.</AbstractText> |
7,163 | Coronary vasospastic crisis leading to cardiogenic shock and recurrent ventricular fibrillation in a patient with long-standing asthma. | Acute myocardial infarction in patients with normal coronary arteries is a therapeutic dilemma. Coronary artery vasospasm and thrombosis are the most commonly encountered clinic problems and appear in localized coronary segments. The incidence of cardiovascular disease is increased in asthmatic patients. ß(2)-Adrenergic agonists use is associated with increased cardiovascular events. Although myocardial ischemia during asthma has been described in literature, acute myocardial infarction and ventricular fibrillation with normal coronary arteries in patients with asthma bronchiale is a rare entity. Our patient with long-standing asthma bronchiale presented with cardiogenic shock whose coronary angiography revealed multivessel disease and undergone primary percutaneous coronary intervention. Due to ongoing chest pain and hemodynamic instability; an early bypass surgery was planned. A control angiogram was performed before surgery. After intracoronary nitrate administration all narrowings in coronary vasculature disappeared. Symptom relief and clinical improvement was achieved with nitrate and calcium channel blockers later. After 2 months she was readmitted with cardiac arrest due to recurrent ventricular fibrillation and intracardiac defibrillator implantation was performed. |
7,164 | Stroke prevention in atrial fibrillation and other major cardiac sources of embolism. | The frequency of cardioembolic stroke is expected to rise as the general population ages. Much of the increase may be attributed to atrial fibrillation, the most common cause of cardioembolic stroke and one that plays a substantial role in aging adults. Other sources of cardioembolic stroke may include ventricular thrombus from myocardial infarction, heart failure, structural heart defects such as patent foramen ovale (PFO), atrial septal aneurysm, proximal aortic atheroma, valvular heart disease, and endocarditis. Diagnostic studies, such as neuroimaging, ECG, and echocardiography, are helpful in uncovering cardioembolic sources of stroke. Medical therapy is predicated on the underlying mechanism. For example, warfarin may be indicated in certain patients who have atrial fibrillation, atrial, or ventricular thrombi, and PFO with atrial septal aneurysm and cryptogenic stroke in select young patients to prevent stroke. Newer diagnostic technologies, including multidetector CT and cardiac MRI, may be useful to diagnose cardiac causes of stroke when transesophageal echocardiography is indeterminate or cryptogenic stroke is present. |
7,165 | Risks and challenges of implantable cardioverter-defibrillators in young adults. | The clinical use of the implantable cardioverter-defibrillator (ICD) is well established to prevent sudden death in patients with left ventricular dysfunction due to coronary artery disease and dilated cardiomyopathy, and its use has saved thousands of lives. More recently, its use has been extended to other patients at risk for sudden cardiac arrest due to ventricular fibrillation: patients with structural heart diseases such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular dysplasia and patients with normal cardiac anatomy and function except for electrophysiologic abnormalities that predispose to cardiac arrest: Brugada syndrome and long QT syndrome. A distinguishing feature of these patients may be the young age when they present for either primary or secondary prevention. This contrasts with the "first wave" of adult ICD implantations that were usually performed in elderly or middle aged patients. An important consideration in favor of ICD implantation in young patients with sudden death risk is the long and cumulative period of their risk. Similarly, after implantation, these patients will experience the long-term risks of ICD implantation. This review focuses on the unique challenges presented by device implantation in young patients 16 to 45 years of age who may have 4 to 7 decades of life with their devices. Although devices may prolong life, they come with problems that will pose unique challenges for both patients and their physicians. Moreover, because of the long durations, these problems may accelerate as patients age. |
7,166 | Recurrent ventricular arrhythmia storms in the age of implantable cardioverter defibrillator therapy: a comprehensive review. | Rapidly recurrent ventricular arrhythmia is not an infrequent clinical entity in the era of implantable cardioverter defibrillator therapy. Clinical presentation can vary dramatically, from multiple defibrillator shocks with hemodynamic instability, to asymptomatic delivery of anti-tachycardia pacing. Although some investigators have reported disparate prognostic implications with electrical storm, in larger trials of both primary and secondary defibrillator populations, electrical storm appears to be a harbinger of cardiac death with a notably high mortality early post event. While acute cessation of electrical storm is generally achievable with medical therapy, it is critical to recognize that the causes for subsequent mortality are often not arrhythmic in nature. Thus, the challenge for cardiovascular practitioners is to maximize substrate based therapy and modification to not only prevent further episodes of electrical storm and possibly curtail the considerable risk of subsequent cardiac mortality. |
7,167 | Ventricular fibrillation following autologous intramyocardial cell therapy for inherited cardiomyopathy. | A 41-year-old male with cardiomyopathy from an inherited beta myosin heavy-chain mutation underwent treatment for heart failure with intramyocardial cell transplantation. He received direct injections into his heart of autologous precursor cells isolated from his blood. He immediately suffered ventricular fibrillation. Although he was resuscitated, he experienced a prolonged downward course that prohibited his undergoing transplantation. His autopsy revealed marked fibrosis throughout the myocardium with areas of mononuclear cell infiltrate. This case highlights the potential adverse effects associated with intramyocardial therapy in the cardiomyopathic heart. |
7,168 | Dynamic changes of left ventricular performance and left atrial volume induced by the mueller maneuver in healthy young adults and implications for obstructive sleep apnea, atrial fibrillation, and heart failure. | Using the Mueller maneuver (MM) to simulate obstructive sleep apnea (OSA), our aim was to investigate acute changes in left-sided cardiac morphologic characteristics and function which might develop with apneas occurring during sleep. Strong evidence supports a relation between OSA and both atrial fibrillation and heart failure. However, acute effects of airway obstruction on cardiac structure and function have not been well defined. In addition, it is unclear how OSA might contribute to the development of atrial fibrillation and heart failure. Echocardiography was used in healthy young adults to measure various parameters of cardiac structure and function. Subjects were studied at baseline, during, and immediately after performance of the MM and after a 10-minute recovery. Continuous heart rate, blood pressure, and pulse oximetry measurements were made. During the MM, left atrial (LA) volume index markedly decreased. Left ventricular (LV) end-systolic dimension increased in association with a decrease in LV ejection fraction. On release of the maneuver, there was a compensatory increase in blood flow to the left side of the heart, with stroke volume, ejection fraction, and cardiac output exceeding baseline. After 10 minutes of recovery, all parameters returned to baseline. In conclusion, sudden imposition of severe negative intrathoracic pressure led to an abrupt decrease in LA volume and a decrease in LV systolic performance. These changes reflected an increase in LV afterload. Repeated swings in afterload burden and chamber volumes may have implications for the future development of atrial fibrillation and heart failure. |
7,169 | Safety of contrast administration for endocardial enhancement during stress echocardiography compared with noncontrast stress. | The aim was to evaluate the safety of stress echocardiography using contrast (CE) for endocardial enhancement compared with a noncontrast (NCE) cohort in a large nonselect population. The recent Food and Drug Administration warning cited lack of data for safety regarding the use of contrast in conjunction with stress echocardiography. A detailed record review was performed for 5,069 consecutive patients who underwent stress echocardiography (58% pharmacologic, 42% exercise) during an 8-year period. Contrast use, hemodynamics, and adverse clinical and electrocardiographic events were evaluated until time of discharge from the laboratory. Contrast was administered to 2,914 patients (58%) and was higher in in-patients (66%) and during dobutamine stress (67%). Compared with the NCE group, the CE group was older (median age 61 vs 58 years) and had more depressed left ventricular ejection fraction <50% (14% vs 11%; all p <0.001). The CE group experienced more chest pain (11% vs 8%; p = 0.001), back pain (0.6% vs 0.05%; p <0.001), and premature ventricular contractions (odds ratio 1.42, 95% confidence interval 1.19 to 1.69, p <0.001). There was no sustained ventricular tachycardia, ventricular fibrillation, cardiac arrest, or death in either group. One uncomplicated acute myocardial infarction and 1 anaphylactoid reaction occurred in the CE group, and none occurred in the NCE group (p = 0.51). Rates of clinically significant arrhythmias were similar in both groups (CE 2.1% vs NCE 1.9%; p = 0.8). In conclusion, although CE of echocardiographic images was used more often in patients with a higher cardiac risk profile, the risk of major adverse events was very small in both the CE and NCE stress echocardiography cohorts. |
7,170 | Relation of mortality to failure to prescribe beta blockers acutely in patients with sustained ventricular tachycardia and ventricular fibrillation following acute myocardial infarction (from the VALsartan In Acute myocardial iNfarcTion trial [VALIANT] Registry). | Sustained ventricular arrhythmias and heart failure are well-recognized complications after acute myocardial infarction (AMI) and have been associated with worse outcomes and increased mortality. The use of and outcomes associated with acute beta-blocker therapy in patients with AMI complicated by sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and heart failure were investigated. Of 5,391 patients in the VALIANT Registry, sustained VT/VF occurred in 306 (5.7%), with an in-hospital mortality rate of 20.3%. Multivariable logistic regression identified sustained VT/VF as a major predictor of in-hospital death (relative risk 4.18, 95% confidence interval 2.91 to 5.93). Of those with sustained VT/VF, 55.2% were treated with intravenous or oral beta blockade in the first 24 hours. After adjusting for baseline characteristics, propensity for acute beta-blocker use, and the interaction between Killip classification and beta-blocker therapy, beta-blocker therapy within 24 hours was associated with decreased in-hospital mortality in patients with sustained VT/VF (relative risk 0.28, 95% confidence interval 0.10 to 0.75, p = 0.013) without evidence of worsening heart failure. Patients with sustained VT/VF were less likely to receive beta blockers within 24 hours (p = 0.001). In conclusion, sustained VT/VF was common after AMI. In patients with sustained VT/VF, beta-blocker therapy in the first 24 hours after AMI was associated with decreased early mortality without worsening heart failure. Unfortunately, beta blockers were underused acutely in patients with sustained VT/VF. |
7,171 | Treatment of patients with heart failure and preserved ejection fraction. | Of the more than 5 million Americans who have heart failure (HF), 30% to 50% have HF with preserved ejection fraction (HF-PEF). HF-PEF commonly occurs in elderly patients, especially women, with comorbidities of hypertension, left ventricular hypertrophy, diabetes, myocardial ischemia, and obesity. HF-PEF is associated with high morbidity and mortality. Although two large multicenter randomized, placebo-controlled trials evaluating an angiotensin-converting enzyme inhibitor (ACEI) and an angiotensin receptor blocker (ARB) in patients with HF-PEF did not demonstrate any statistically significant benefit in their primary end points, they did suggest that these agents may have a modest role in reducing HF hospitalizations. Although calcium channel blockers and beta-blockers may be of benefit in patients with HF-PEF, large clinical trial data are not available to support their routine use in all patients with HF-PEF. Subgroup analysis does not support the use of digoxin in patients with HF-PEF in sinus rhythm. Current therapeutic recommendations for HF-PEF are aimed at 1) management of HF symptoms with sodium and fluid restriction along with diuretics for volume overload and 2) treatment of concomitant comorbidities, especially hypertension, rate and possibly rhythm control of atrial fibrillation, and evaluation and treatment of myocardial ischemia and anemia. ACEIs, ARBs, calcium channel blockers, and beta-blockers are recommended for HF-PEF patients who have other established indications for their use. Results are awaited from ongoing clinical trials with another ARB, irbesartan, and an aldosterone blocker, spironolactone. |
7,172 | Pharmacokinetics of ibutilide in patients with heart failure due to left ventricular systolic dysfunction. | To assess whether the increased risk of ibutilide-induced torsade de pointes in patients with heart failure may be due to increased ibutilide exposure, we sought to determine if the pharmacokinetics of ibutilide are altered in patients with heart failure due to left ventricular systolic dysfunction.</AbstractText>Multicenter, prospective pharmacokinetic study.</AbstractText>Four academic medical centers in the United States.</AbstractText>Sixteen adult patients with atrial fibrillation or atrial flutter requiring conversion to normal sinus rhythm: six patients who had New York Heart Association (NYHA) class II or III heart failure due to left ventricular dysfunction (mean +/- SD left ventricular ejection fraction [LVEF] 30 +/- 9%); 10 patients who did not have left ventricular dysfunction (mean +/- SD LVEF 54 +/- 5% in six of these 10 patients) served as controls.</AbstractText>All patients received a single dose of ibutilide 1.0 mg administered intravenously over 10 minutes. Blood samples were obtained through an indwelling catheter in the contralateral arm before ibutilide administration, at the end of the infusion, and at 5, 15, 30, 45 minutes and 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24, and 48 hours after the infusion.</AbstractText>Serum ibutilide concentrations were determined by using high-performance liquid chromatography and mass spectrometry. No significant differences were noted between the heart failure and normal left ventricular function groups in the following parameters: maximum serum ibutilide concentration (median [interquartile range] 3.8 [2.3-5.7] vs 5.8 [3.1-14.4] microg/L, p=0.31), area under the serum concentration-time curve from time zero extrapolated to infinity (mean +/- SD 11.0 +/- 9.4 vs 13.2 +/- 10.6 microg*hr/L, p=0.88), steady-state volume of distribution (1380 +/- 334 vs 1390 +/- 964 L, p=0.99), systemic clearance (129 +/- 60 vs 125 +/- 81 L/hr, p=0.92), or half-life (12.5 +/- 10.7 vs 12.4 +/- 8.6 hrs, p=0.99).</AbstractText>The pharmacokinetics of ibutilide do not appear to be altered in patients with NYHA class II or III heart failure due to left ventricular systolic dysfunction. Therefore, the increased risk of ibutilide-induced torsade de pointes in patients with heart failure does not appear to be due to increased ibutilide exposure.</AbstractText> |
7,173 | [Effects of sympathetic nerve stimulation on connexin43 and ventricular arrhythmias during acute myocardial ischemia: experiment with rats]. | To investigate the effects of sympathetic nerve stimulation (SNS) on connexin43 (Cx43) and ventricular arrhythmias during acute myocardial ischemia (MI).</AbstractText>Ninety five Wistar rats were randomly divided into four groups: MI group (n=25), undergoing: ligation of the anterior descending coronary; MII-SNS group (n=25); undergoing electric stimulation of sympathetic nerve since the beginning of ligation of the anterior descending coronary and lasting till 30 min after the ligation, sympathetic nerve stimulation preconditioning + myocardial ischemia (pSNS-MI) group (n=25), undergoing electric stimulation of sympathetic nerve since the beginning of ligation of the anterior descending coronary that ended just after the ligation; and sham operation (SO) group (n=20), without coronary ligation. Ventricular arrhythmias were monitored by electrocardiography. Western blotting and RT-PCR were used to detect the protein and mRNA expression of Cx43 respectively. Immunofluorescence analysis was used to observe the changes of Cx43 protein distribution.</AbstractText>One and 3 rate died due to ventricular fibrillation in the MI group and MI-SS group respectively. The incidence of ventricular tachycardia (VT)/VF within 30-minute after ligation in the MI-SNS group was 80.0%, significant higher than that of the MI group (52.0%, P < 0.05). The incidence of VT/VF within 30-minute after ligation of the pSNS-MI group was 20.0%, significantly lower than that of the MI-SNS group (P < 0.05). 30 minutes after the ligation, the percentage of phosphorylated Cx43 of the pSNS-MI and MI-SNS groups were 71.2% +/- 7.0% and 73.4% +/- 6.7% respectively, both significantly higher than that of the MI group (46.7% +/- 6.3%) (both P < 0.05). The total contents of Cx43 of the MI and pSNS-MI groups were 1.29 +/- 0.14 and 1.25 +/- 0.13 respectively, both similar to that of the SO group [(1.30 +/- 0.10), both P > 0.05], while the total Cr43 content of the MI-SNS group was 0.73 +/- 0. 12, significantly lower than that of the SO group [(1.30 +/- 0.10), P < 0.05]. The Cx43 mRNA levels of the 3 experimental groups were all significantly lower than that of the SO group (all P < 0.05). Immunofluorescence analysis confirmed that ischemia and sympathetic nerve stimulation induced the changes of connexin43 distribution and sympathetic nerve stimulation preconditioning inhibited the changes of connexin43 distribution induced by ischemia.</AbstractText>SNS promotes ventricular arrhythmias by promoting Cx43 degradation, and sympathetic nerve stimulation preconditioning inhibits ventricular arrhythmias by preventing Cx43 dephosphorylation.</AbstractText> |
7,174 | A new completely flexible ring for mitral valve annuloplasty: the "Rama-Valvuloplasty-Ring". Five-year Pitié Salpétrière experience. | The aim of this study was to analyze the effects about the use of a new completely flexible ring for mitral valve anuloplasty, the "Rama-Valvuloplasty-ring", in 182 patients operated on in the Pitié-Salpétrière Hospital, Paris, France for mitral valve regurgitation (MVR). From January 1998 to December 2003, 182 patients with mitral regurgitation (MR) underwent mitral reconstructive surgery at our institution with the "Rama-Valvuloplasty-Ring". This group was made up of 117 men (64.3%) and 65 women (35.7%). The age ranged from 19 to 87 years (mean 62.51 +/- 8.2 years). The patients surviving the operation were the subject of a prospective follow-up. In the preoperative stage sinus rhythm was found in 71.97% (131) of patients and atrial fibrillation in the remaining 28.03% (51) of patients. The mean NYHA FC was 2.9 +/- 1.7 and subdivided as follows: 65 patients in FC I-II (35.72%), 104 patients in FC III (57.14%) and 13 patients in FC IV (7.14%). Most of the patients have shown, in the preoperative echocardiogram, grade II M.R. (46.15% N. 84) and grade III M.R. (29.12%, N.53); 24.72% of the patients (N. 45) had grade IV M.R. The mean E.F. was 42.8 +/- 9.7%. Left ventricular end diastolic diameter (LVEDD) was 57.7 +/- 9.7 mm. The causes of mitral valve insufficiency were degenerative disease in 141 patients (77.47%), post-ischemic disease in 21 patients (11.53%), rheumatic valvular disease in 11 patients (6.05%) and infectious endocarditis in 9 patients (4.95%). All the patients were operated using the Rama-Valvuloplasty-Ring. Ring sizes most commonly used were 30 mm and 32 mm, respectively in 92 patients (50.55%) and 41 patients (22.54%), followed by 28 mm (43 patients, 23.62%), 34 mm (5 patients, 2.74%), 36 mm (1 patient, 0.55%). The surgical tecnique was valve quadrangular resection in 103 patients (56.60%), triangular resection in 57 patients (31.32%) and no valve resection in 22 patients (12.08%). Among the above, 89 patients (48.90%) underwent an associated intervention as follows: 44 patients (24.18%) underwent coronary revascularization: 18 patients (9.89%) with single by-pass surgery, 21 patients (11.54%) with double by-pass, 5 patients with triple by-pass (2.75%); 42 patients (23.07) underwent aortic valve replacement (AVR); 3 patients (1.65%) underwent aortic repair. Early postoperative mortality was 2.19% (4 of 182 patients). Early postoperative echocardiographic control showed MR grade 0 in 142 patients (79.78%) and grade I in 36 (20.22%) with mean grade 0.4 +/- 0.12; no patients with grade III or IV. Therefore, there was no mitral annuloplasty failure requiring valve replacement (MVR). During the follow-up there were 12 late deaths (12 of 178 patients, 6.74%). Only one death was valve-related (thrombosis) whereas the other 11 ones were non cardiac-related deaths (subdural frontal haematoma, septic shock). Postoperative transthoracic echocardiogram data were available in 166 patients at 5 years: the presence of postoperative MR was evaluated and severity was graded as mild in 33 patients (19.88%), moderate in 18 patients (10.84%), severe in 3 (1.81%) patients. There was no MR in the other 112 patients (67.47%); LVEDD was 49.4 +/- 6.5 mm; EF was 51.8 +/- 4.3%. The mean NYHA FC was 0.8 +/- 0.4. Only one patient was reoperated on during the follow-up because of mitral annuloplasty failure with MVR. In conclusion, mid-term 5-years follow up is good for patients operated on with the new completely flexible Rama-Valvuloplasty-Ring for mitral annuloplasty. This study has also verified the advantage about the Rama-Valvuloplasty-Ring use in the preservation of native valve apparatus. |
7,175 | Transplantation of bone marrow mononuclear cells does not affect postinfarction electrical remodeling of the heart. | We studied the effect of allotransplantation of bone marrow mononuclear cells on postinfarction remodeling of the heart in rats. The cells were transplanted into the periinfarction zone of the heart. The transplantation was performed on day 9 after coronary occlusion. It was found that on day 45 after coronary occlusion myocardial hypertrophy developed, ventricular fibrillation threshold decreased, but myocardial contractility remained within the normal. Allotransplantation of bone marrow mononuclear cells had no effect on myocardial hypertrophy and did not prevent the development of electrical instability of the heart. |
7,176 | Maternal cardiac arrest in early pregnancy. | A primigravid woman suffered a prolonged cardiac arrest at 18 weeks of gestation. Dilated ischemic cardiomyopathy was diagnosed. After recovery, the patient received an implantable cardioverter-defibrillator. At 38 weeks of gestation she had an elective caesarean delivery. Both mother and child had a favourable outcome. The effect of pregnancy on underlying cardiac disease and the management of maternal cardiac arrest with a pre-viable fetus are discussed. The importance of a multidisciplinary approach is emphasized. Continued neurodevelopmental assessment of the newborn is necessary to detect the long-term effects of fetal hypoxia in early pregnancy. |
7,177 | Precordial steering wheel: a fortunate accident. | Myocardial ischemia has been associated with motor vehicle collisions (MVCs). However, we were unable to find reported cases of ST-segment elevation myocardial infarction (STEMI) leading to ventricular tachyarrhythmia and subsequent MVC. In such patients, decisions regarding antiplatelet and antithrombotic therapy need to balance the risk of ongoing myocardial ischemia and hemorrhage.</AbstractText>To describe a case of STEMI and ventricular fibrillation (VF) associated with a head-on MVC, and to describe the management decisions involved in the care of such a patient.</AbstractText>A 47-year-old man presented to the Emergency Department after a single-car head-on collision with a wall at high speed. He had a facial degloving injury as well as right-sided flail chest. An electrocardiogram demonstrated ST-segment elevation in the inferior and anterior leads. Due to the patient's significant traumatic injuries, he underwent a rapid trauma evaluation and was transferred for emergent cardiac catheterization, which demonstrated evidence of plaque rupture in the right coronary artery (RCA). Flow distal to the lesion was preserved, so stent implantation was initially deferred out of concern for hemorrhage secondary to the aggressive antiplatelet and antithrombotic regimen requisite with stent implantation. The patient then went into VF in the cardiac catheterization laboratory, and repeat angiography demonstrated an occluded RCA, and the patient underwent successful stent implantation.</AbstractText>The management of STEMI in the setting of trauma is complex. Pharmacologic agents used in STEMI increase the risk of bleeding, and management must balance the risk of prolonged ischemia with the risk of hemorrhage.</AbstractText>Copyright © 2011 Elsevier Inc. All rights reserved.</CopyrightInformation> |
7,178 | Action potential dynamics explain arrhythmic vulnerability in human heart failure: a clinical and modeling study implicating abnormal calcium handling. | The purpose of this study was to determine whether abnormalities of calcium cycling explain ventricular action potential (AP) oscillations and cause electrocardiogram T-wave alternans (TWA).</AbstractText>Mechanisms explaining why heart failure patients are at risk for malignant ventricular arrhythmias (ventricular tachycardia [VT]/ventricular fibrillation [VF]) are unclear. We studied whether oscillations in human ventricular AP explain TWA and predict VT/VF, and used computer modeling to suggest potential cellular mechanisms.</AbstractText>We studied 53 patients with left ventricular ejection fraction 28 +/- 8% and 18 control subjects. Monophasic APs were recorded in the right ventricle (n = 62) and/or left ventricle (n = 9) at 109 beats/min.</AbstractText>Alternans of AP amplitude, computed spectrally, had higher magnitude in study patients than in controls (p = 0.03), particularly in AP phase II (p = 0.02) rather than phase III (p = 0.10). The AP duration and activation restitution (n = 11 patients) were flat at 109 beats/min and did not explain TWA. In computer simulations, only reduced sarcoplasmic reticulum calcium uptake explained our results, causing calcium oscillations, AP amplitude alternans, and TWA that were all abolished by calcium clamping. On prospective follow-up for 949 +/- 553 days, 17 patients had VT/VF. The AP amplitude alternans predicted VT/VF (p = 0.04), and was 78% concordant with simultaneous TWA (p = 0.003).</AbstractText>Patients with systolic dysfunction show ventricular AP amplitude alternans that prospectively predicted VT/VF. Alternans in AP amplitude, but not variations in AP duration or conduction, explained TWA at < or =109 beats/min. In computer models, these findings were best explained by reduced sarcoplasmic reticulum calcium uptake. Thus, in heart failure patients, in vivo AP alternans may reflect cellular calcium abnormalities and provide a mechanistic link with VT/VF.</AbstractText> |
7,179 | [Treatment of atrial fibrillation in every days practice]. | Atrial fibrillation is the most common arrhythmia in the adult. During recent years the therapeutic strategy has markedly changed. Some of these changes can be summarized as follows: Basis therapy includes betablockers and - in patients with structural heart disease - ACE-inhibitors and AT(1)-Blockers respectively. Class 1C-antiarrhythmic agents (flecainide or propafenon) should be restricted to patients with no or minimal left ventricular impairment. Amiodaron is the drug of choice in patients refractory to class 1C-agents and in those with already reduced left ventricular function. The "pill-in-the-pocket" regime can be used successfully in patients without structural heart disease and rare episodes of atrial fibrillation.Catheter ablation for paroxysmal and short lasting chronic atrial fibrillation was introduced into the clinical practice in 2006. The European and US-American guidelines recommend this technique for patients with no or minimal structural heart disease who are highly symptomatic and refractory or intolerant to antiarrhythmic agents. Decisions for curative catheter ablation in patients with long standing atrial fibrillation, heart failure or valvular heart disease should be individualized but are to date not generally recommended. |
7,180 | Ventricular rate control using a novel vagus nerve stimulating system in a dog with chronic atrial fibrillation. | A 4-year-old, intact male Dogue de Bordeaux dog with congenital valvular pulmonic stenosis, tricuspid valve dysplasia, and chronic atrial fibrillation underwent ultrasound-guided balloon valvuloplasty in addition to pharmacological treatment. Owner compliance to prescribed pharmacotherapy proved very poor, and concerns developed regarding the ability to successfully control heart rate and symptoms using drug therapy alone. These concerns were addressed by the implantation of a novel vagal stimulation system that was programmed to prevent a ventricular rate of >145 bpm. Consequently, post-operative ventricular response rate decreased from up to 250 to 140 bpm. Successful ventricular rate control was maintained for 291 days post-operatively, following which euthanasia was elected by the owner due to persistent right-sided congestive heart failure. To the authors' knowledge, this is the first report of successful continuous rate control using a vagal stimulating system in a closed-chest, client-owned dog with chronic atrial fibrillation secondary to spontaneously occurring organic heart disease. |
7,181 | Antiarrhythmic effect of reverse ventricular remodeling induced by cardiac resynchronization therapy: the InSync ICD (Implantable Cardioverter-Defibrillator) Italian Registry. | We investigated whether the reverse remodeling after cardiac resynchronization therapy (CRT) might reduce the occurrence of ventricular arrhythmias (VAs).</AbstractText>It is currently debated whether CRT has an effect on the burden of VAs.</AbstractText>The study included 398 patients treated with a CRT defibrillator and with a follow-up of at least 12 months. Spontaneous VAs detected by the device were reviewed and validated.</AbstractText>A significant reduction in VA episodes and shock therapies was evident during the follow-up with greater decrease after 1 month. After 6 months of CRT, 227 patients (57%) showed a reduction in end-systolic volume of >or=10% and were defined as "responders." The baseline characteristics were similar between the responders and the nonresponders. Nonetheless, the proportion of patients with recurrence of VA after 1 month of CRT was significantly lower in responders (32% vs. 43%, p = 0.024). Among baseline variables no parameters emerged as predictors of tachyarrhythmia recurrence. However, receiver-operating curve analysis recognized a reduction of left ventricular end-systolic volume at 6 months of 13% as the best cutoff to identify the reduction of VAs (with a sensitivity of 58% and a specificity of 54%).</AbstractText>In patients treated with CRT defibrillators, a reduction in ventricular arrhythmic events occurs during the initial 12 months after implant and is correlated with the degree of ventricular remodeling induced by the therapy. Patients demonstrating reverse remodeling at midterm follow-up show a reduction in arrhythmias soon after the implant, pronounced improvements at long-term, and a better survival.</AbstractText> |
7,182 | Atrial Arrhythmias in long-QT syndrome under daily life conditions: a nested case control study. | The long-QT syndromes (LQTS) are inherited electrical cardiomyopathies characterized by prolonged ventricular repolarization and ventricular arrhythmias. Several genetic reports have associated defects in LQTS-causing genes with atrial fibrillation (AF). We therefore studied whether atrial arrhythmias occur in patients with LQTS under daily-life conditions.</AbstractText>We systematically assessed atrial arrhythmias in LQTS patients and matched controls using implanted defibrillators or pacemakers as monitors of atrial rhythm in a nested case-control study. Twenty-one LQTS patients (3 male; 39 +/- 18 years old; 18 on beta blocker, ICD therapy duration 6.3 +/- 2.7 years; 4 LQT1, 6 LQT2, 2 LQT3) were matched to 21 control subjects (13 male; 50 +/- 19 years old; 3 on beta blocker; pacemaker therapy duration 8.5 +/- 5.5 years; 19 higher-degree AV block, 2 others). LQTS patients were identified by a systematic search of the LQTS patient databases in Münster and Munich.</AbstractText>One-third (7 of 21) of the LQTS patients developed self-terminating atrial arrhythmias (atrial cycle lengths <250 ms). Only one control patient developed a single episode of postoperative AF (P < 0.05 vs LQTS).</AbstractText>LQTS patients at high risk for ventricular arrhythmias may develop short-lasting atrial arrhythmias under daily-life conditions, suggesting that prolonged atrial repolarization may contribute to the initiation of AF.</AbstractText> |
7,183 | [Underestimation of renal risk in cardiology clinics. RICAR study]. | The aim of this study was to assess the rate of patients attended in cardiology outpatient clinics in whom microalbumine or glomerular filtration rate had been determined, at least once, in the previous 12 months.</AbstractText>It was an observational, transversal, multicentric study. 1224 patients were included from 124 centers in Spain. Epidemiological, anthropometric, analytic and electrocardiographic data were recruited. Glomerular filtration rate was calculated thereafter by means of the simplified equation of the MDRD. Results. Microalbumine was determined in 34% of the patients, of those 49% had positive microalbumine. Microalbumine rates were higher in patients with diabetes, heart failure, atrial fibrillation, peripheral artery disease or serum creatinine levels > 1.3 mg/dl. However, only young patients, diabetics and those with left ventricular hypertrophy had this exam performed more often. The glomerular filtration rate was determined in 11% of the patients. 30% of the population had moderate or severe renal dysfunction (filtration rate < 60 ml/min) and only 21% of the population hat normal renal function (filtration rate > 90 ml/min). Glomerular filtration rate was assessed more frequently in patients with serum creatinine > 1.3 mg/dl and those with history of heart failure.</AbstractText>The prevalence of renal dysfunction in hypertensive patients attended in Cardiology clinics is high. However, the methods recommended for early detection of renal dysfunction are scarcely used by cardiologists. These figures do not improve significantly in high risk patients.</AbstractText> |
7,184 | [Basic and advanced resuscitation of children]. | The ERC Guidelines 2005 regarding the resuscitation of children and neonates recommend changes in treatment algorithms. Cardiac arrest in children is most often caused or worsened by hypoxic conditions. On confirmation of cardiac arrest in a child, treatment is initiated with 5 ventilations and continued with alternating cycles of 15 chest compressions and 2 ventilations. Defibrillation of ventricular fibrillation or pulseless ventricular tachycardia is given as single 4 J per kg(-1) shock in every cycle. Rhythm or pulse is not assessed immediately after defibrillation, but first after two minutes of basic life support, i.e. before a new attempt of defibrillation. |
7,185 | Acute left atrial thrombosis during anticoagulant therapy in a patient with antithrombin deficiency. | A 47-year-old woman presented to our clinic 1 day after an intervention for a tibial shaft fracture because of sudden onset of chest pain and palpitations. Hospital drug therapy included enoxaparin. The ECG showed atrial fibrillation with a rapid ventricular rate. Transthoracic echocardiography showed a mass in the LA. Transoesophageal echocardiography (TEE) was performed which showed a multilobulated liquid-filled mass (3.6 x 3.7 cm), adherent to the septal, anterior and posterolateral LA most consistent with thrombosis. Tests for hypercoagulable disorders revealed antithrombin deficiency (antithrombin-heparin co-factor level = 30% [normal pooled plasma activity 70%-140%]), suggesting that it played an outstanding role in the LA thrombosis. After initial stabilization, the patient was discharged with warfarin (target INR = 2.5-3.5) together with beta-blockers, statins and metformin. After 1 month of follow-up the patient underwent TEE which showed a dramatic reduction of the left atrial thrombosis. Our patient is doing well and is continuing life-long anticoagulant therapy. |
7,186 | Idiopathic spontaneous coronary artery dissection: a case report. | Spontaneous coronary artery dissection frequently causes death, and most cases are diagnosed at autopsy. In most cases the affected persons are young pregnant females or women in the early postpartum period. We report a case of a female aged 36. She complained of acute chest pain and had ventricular fibrillation. She recovered after successful defibrillation. The coronary angiogram revealed dissection in the proximal left anterior descending artery. ST segment elevation was demonstrated on the electrocardiogram and the patient continued to have chest pains and underwent a coronary bypass operation. The etiology of spontaneous coronary artery dissection is still obscure and is mostly seen in young females. Early surgical intervention and stenting may save lives. |
7,187 | Congestive heart failure with and without atrial fibrillation - different patient populations? | Heart failure (HF) and atrial fibrillation (AF) are common comorbid conditions in hospitalised patients. AF may occur when left ventricular (LV) systolic function deteriorates. The aim was to compare HF patients with AF to patients in sinus rhythm (SR).</AbstractText>Echocardiography and a cardiopulmonary exercise test were performed in 67 patients with HF. Peak VO(2) was determined, as were LV-mass, enddiastolic, endsystolic volume indices (EDVI, ESVI), and ejection fraction (EF).</AbstractText>EF tended to be higher in AF compared to SR patients (39+/-10 vs. 31+/-10%), LV volume indices were smaller (ESVI:35+/-19 vs. 59+/-25 ml/m(2), p<0.0001, EDVI:56+/-24 vs. 83+/-29 ml/m(2), p<0.001). LV hypertrophy was prevalent (59% vs. 63%) and concentric hypertrophy tended to be more common with AF (50% vs. 21%). Peak VO(2) was similarly reduced in AF and SR (11.4+/-3.2 vs. 12.1+/-4.3 ml/kg*min).</AbstractText>HF patients with AF compared to SR tend to have smaller LV volumes, less compromised systolic function and more frequent LV concentric hypertrophy. Our study supports the concept that AF in HF indicates a different patient population rather than an effect of progressive LV systolic dysfunction.</AbstractText> |
7,188 | Arrhythmias in patients with chronic obstructive pulmonary disease (COPD): occurrence frequency and the effect of treatment with the inhaled long-acting beta2-agonists arformoterol and salmeterol. | Beta-adrenergic stimulation may increase heart rate and the potential for cardiac arrhythmias. The effect of inhaled long-acting beta2-agonists (LABAs) on these outcomes was evaluated in patients with chronic obstructive pulmonary disease (COPD) in 2 double-blind randomized clinical trials. The pretreatment arrhythmia occurrence frequency in these patients was also described. In this analysis, 24-hour Holter monitoring data were pooled from 2 identically designed Phase III trials. Patients were randomized to LABA treatment or placebo for 12 weeks: a) nebulized arformoterol 15 microg BID, b) 25 microg BID, or c) 50 microg QD; d) salmeterol metered dose inhaler 42 microg BID; or e) placebo. The 24-hour Holter monitoring was performed pretreatment and at Weeks 0 (first day of dosing), 6, and 12. We assessed the proportion of patients with each of 4 arrhythmias: atrial tachycardia, atrial fibrillation/flutter, and "nonsustained"; (4-10 beats) and "sustained"; (>10 beats) ventricular tachycardia. There were 5226 Holter recordings in 1429 treated patients. At baseline, there was a low frequency of occurrence of atrial fibrillation/flutter (0.1%), nonsustained ventricular tachycardia (3.1%), and >10 beat ventricular tachycardia (0.3%). Atrial tachycardia occurred frequently (41.8%). The proportion of patients with treatment-emergent atrial tachycardia ranged from 27% to 32% and was non-significantly higher, by approximately 2%-5% (p = 0.70), in the LABA groups compared with the placebo group. The rates of the other more serious arrhythmias did not increase with LABA treatment and were similar to placebo. All treatment groups (LABA and placebo) had consistent small decreases from baseline in mean 24-hour and maximum hourly heart rate. In conclusion, in this large cohort of COPD patients with no or stable cardiac comorbidities, a high proportion ( approximately 40%) of patients were observed to have atrial tachycardia before treatment, which increased by 2%-5% with LABA treatment. More serious arrhythmias were infrequent and did not increase with inhaled LABA therapy. LABA administration did not increase mean heart rate. |
7,189 | Pre-ablative predictors of atrial fibrillation recurrence following pulmonary vein isolation: the potential role of inflammation. | An increasing body of evidence has demonstrated the essential role of inflammation in the genesis and maintenance of atrial fibrillation (AF). The aim of the present study was to investigate whether success or failure of electrical pulmonary vein isolation (PVI) in patients with AF is related with the presence of a pre-ablative inflammatory state as determined by known clinical parameters and conventional markers of inflammation including high-sensitivity C-reactive protein, white blood cell (WBC) count, and fibrinogen.</AbstractText>Seventy-two patients with paroxysmal (64%) or persistent AF (36%) underwent successful electrical PVI. The mean duration of arrhythmia was 5.5 +/- 2.9 years. After a mean follow-up period of 12.5 +/- 5.7 months, 44 patients (61%) were in sinus rhythm. In univariate Cox proportional hazard regression analysis, hypertension, body mass index (BMI), left ventricular ejection fraction, left ventricular end-diastolic diameter, left atrial diameter (LAD), WBC count, and high-sensitivity C-reactive protein were significantly associated with AF recurrence (P < 0.05). In multivariate Cox proportional hazard regression analysis, hypertension [hazard ratio (HR) 3.127; 95% confidence interval (CI) 1.269-7.706, P = 0.013], LAD (HR 1.077; 95% CI 1.014-1.144, P = 0.015), and WBC count (HR 1.423; 95% CI 1.067-1.897, P = 0.016) were independent pre-ablative predictors of AF recurrence following PVI.</AbstractText>Conventional markers of the inflammatory cascade such as WBC count and high-sensitivity C-reactive protein as well as elements of the metabolic syndrome such as hypertension and increased BMI were significantly associated with AF recurrence. The impact of a pre-ablative inflammatory state in the overall success rate of PVI needs further elucidation.</AbstractText> |
7,190 | d,l-Sotalol at therapeutic concentrations facilitates the occurrence of long-lasting non-stationary reentry during ventricular fibrillation in isolated rabbit hearts. | The effects of d,l-sotalol at therapeutic concentrations (<or=10 mg/L) on wavefront dynamics during ventricular fibrillation (VF) and electrophysiological heterogeneity remain unclear.</AbstractText>By using an optical mapping system, epicardial activation patterns of VF were studied in 6 Langendorff-perfused rabbit hearts at baseline, during 10 mg/L d,l-sotalol infusion, and after washout. In an additional 4 hearts, action potential duration (APD), conduction velocity, and wavelength (WL) restitutions were determined. During d,l-sotalol infusion, VF was terminated in 3 of the 6 hearts. Only 1 heart developed transient ventricular tachycardia (VT). d,l-Sotalol reduced the number of phase singularities (ie, wavebreak) during VF (P<0.05), and it also increased the occurrence frequency (P<0.05) and lifespan (P<0.05) of epicardial reentry during VF. These reentries were non-stationary in nature and did not anchor on anatomical structures. Restitution data showed that d,l-sotalol flattened APD restitution. Furthermore, APD dispersion and spatial heterogeneity of restitutions were not enhanced by d,l-sotalol.</AbstractText>d,l-Sotalol at therapeutic concentrations decreased wavebreak and facilitated the occurrence of long-lasting, non-stationary reentry during VF. However, VT rarely occurred. The related mechanisms include: (1) flattening of APD restitution without enhancement of spatial heterogeneity of electrophysiological properties, causing wavefront organization, and (2) WL prolongation, preventing steady anchoring of reentry.</AbstractText> |
7,191 | Gender differences in clinical manifestations of Brugada syndrome. | We sought to assess differences in phenotype and prognosis between men and women in a large population of patients with Brugada syndrome.</AbstractText>A male predominance has been reported in the Brugada syndrome. No specific data are available, however, concerning gender differences in the clinical manifestations and their role in prognosis.</AbstractText>Patients with Brugada syndrome were prospectively included in the study. Data on baseline characteristics, electrocardiogram parameters before and after pharmacological test, and events in follow-up were recorded for all patients.</AbstractText>Among 384 patients, 272 (70.8%) were men and 112 (29.2%) women. At inclusion, men had experienced syncope more frequently (18%) or aborted sudden cardiac death (6%) than women (14% and 1%, respectively, p = 0.04). Men also had greater rates of spontaneous type-1 electrocardiogram, greater ST-segment elevation, and greater inducibility of ventricular fibrillation (p < 0.001 for all). Conversely, conduction parameters and corrected QT intervals significantly increased more in women in response to sodium blockers (p = 0.03 and p = 0.001, respectively). During a mean follow-up of 58 +/- 48 months, sudden cardiac death or documented ventricular fibrillation occurred in 31 men (11.6%) and 3 women (2.8%; p = 0.003). The presence of previous symptoms was the most important predictor for cardiac events in men, whereas a longer PR interval was identified among those women with a greater risk in this series.</AbstractText>Men with Brugada syndrome present with a greater risk clinical profile than women and have a worse prognosis. Although classical risk factors identify male patients with worse outcome, conduction disturbances could be a marker of risk in the female population.</AbstractText> |
7,192 | [Ventricular fibrillation in acute myocardial infarction - do genes play a role?]. | We present two patients with ventricular fibrillation (VF) during acute myocardial infarction (AMI). First patient had torsade de pointes ventricular tachycardia episodes degenerating into VF 10 days after AMI treated with primary angioplasty. Second patient had multiple episodes of VF during the first day of AMI. He showed ST-segment elevation resembling Brugada pattern. We hypothesise that shape of ST-segment elevation during AMI might be important in assessing risk for VF. We propose that such 'arrhythmogenic' ST elevation might result more from systolic rather than diastolic current of injury during AMI. We discuss genetic predispositions (latent channellopathies) for VF during AMI. |
7,193 | High-normal thyroid function and risk of atrial fibrillation: the Rotterdam study. | Overt and subclinical hyperthyroidism are both well-known independent risk factors for atrial fibrillation. We aimed to investigate the association of high-normal thyroid function with the development of atrial fibrillation in a prospective population-based study in the elderly.</AbstractText>The association between thyroid-stimulating hormone (TSH) levels and atrial fibrillation was examined in 1426 subjects with TSH levels in the normal range (0.4-4.0 mU/L) and without atrial fibrillation at baseline. In 1177 of the 1426 persons in this group, we also examined the association between free thyroxine levels within the normal range (0.86-1.94 ng/dL [to convert to picomoles per liter, multiply by 12.871]) and atrial fibrillation. During a median follow-up of 8 years, 105 new cases of atrial fibrillation were identified. Hazard ratios (HRs) were calculated with 95% confidence intervals (CIs) using Cox proportional hazards models after adjustment for age, sex, current smoking, former smoking, body mass index, systolic blood pressure, hypertension, history of myocardial infarction, presence of heart failure, left ventricular hypertrophy on the electrocardiogram, diabetes mellitus, total cholesterol level, and time of the drawing of blood samples.</AbstractText>The risk of atrial fibrillation was associated with the TSH level. The multivariate adjusted HR was 1.94 (95% CI, 1.13-3.34, lowest vs highest quartile; P for trend, .02). The multivariate adjusted level of free thyroxine showed a graded association with risk of atrial fibrillation (HR, 1.62; 95% CI, 0.84-3.14, highest vs lowest quartile; P for trend, .06).</AbstractText>Within the normal range of thyroid parameters, persons with high-normal thyroid function are at an increased risk of atrial fibrillation.</AbstractText> |
7,194 | Serum intact parathyroid hormone levels predict hospitalisation for heart failure. | To assess whether circulating levels of intact parathyroid hormone (intact PTH) in outpatients predict hospitalisation for heart failure (HF).</AbstractText>Eighty-eight consecutive outpatients with HF were enrolled in the study. The independent association between intact PTH and hospitalisation for HF was assessed using Cox regression analysis.</AbstractText>Mean (SD) serum intact PTH levels significantly increased as New York Heart Association classes increased (I: 40 (21), II: 55 (24), III: 76 (46), IV: 131 (45) pg/ml). The receiver operating characteristic (ROC) curves showed intact PTH levels >or=47 pg/ml to be the optimal cut-off points for hospitalisation for HF, with sensitivity 87%, specificity 71% and area under the ROC curve 0.82 (95% CI 0.72 to 0.91). After adjustment for variables accepted to be predictors for hospitalisation due to HF (age, gender, hypertension, diabetes mellitus, atrial fibrillation, ischaemic heart disease, left ventricular ejection fraction, B-type natriuretic peptide, estimated glomerular filtration rate and cardiac drugs), intact PTH levels >or=47 pg/ml were associated with a hazard ratio of 7.13 for hospitalisation for HF (95% CI 1.79 to 28.4).</AbstractText>Serum intact PTH levels obtained in outpatients with HF were shown to be an independent predictor of hospitalisation for HF.</AbstractText> |
7,195 | Atrial and ventricular electrical and contractile remodeling and reverse remodeling owing to short-term pacing-induced atrial fibrillation in horses. | In humans, atrial fibrillation (AF) induces electrical, contractile, and structural remodeling leading to AF stabilization. Little is known about AF-induced atrial remodeling in horses.</AbstractText>Induced AF produces rapid atrial electrical and contractile remodeling in horses.</AbstractText>Six horses, 5 animals completed the study.</AbstractText>Each horse was instrumented with a pulse generator and pacemaker to maintain AF by burst pacing and to study atrial and ventricular electrophysiology (AF cycle length [AFCL], AF duration, and atrial/ventricular effective refractory period [AERP/VERP] at different pacing cycle lengths [PCL]). Left atrial and ventricular contractile remodeling were assessed echocardiographically by calculation of fractional changes in atrial and ventricular dimensions, respectively, during the cardiac cycle. Measurements were performed at baseline, a 7-day AF period and a 2-day recovery period.</AbstractText>Atrial electrical and contractile remodeling could be demonstrated after 4 and 12 hours of AF, respectively. A progressive shortening of the AERP (261 +/- 39-171 +/- 18 ms at a PCL of 1,000 ms, P < .0001), an attenuation of the AERP rate adaptation, a decrease in AFCL (239 +/- 39-194 +/- 7 ms, P < .0001), and a decrease in atrial FS (12 +/- 3% to 0 +/- 2%, P < .05) occurred. AF duration increased progressively and became persistent in 2 animals. VERP did not change significantly. Upon restoration of sinus rhythm, values returned to baseline within 48 hours.</AbstractText>Atrial electrical and contractile remodeling appears rapidly. After 7 days of AF, reverse remodeling occurred within 2 days. These observations suggest that early conversion of AF might be beneficial for success rate and early return to training.</AbstractText> |
7,196 | Control of scroll-wave turbulence using resonant perturbations. | Turbulence of scroll waves is a sort of spatiotemporal chaos that exists in three-dimensional excitable media. Cardiac tissue and the Belousov-Zhabotinsky reaction are examples of such media. In cardiac tissue, chaotic behavior is believed to underlie fibrillation which, without intervention, precedes cardiac death. In this study we investigate suppression of the turbulence using stimulation of two different types, "modulation of excitability" and "extra transmembrane current." With cardiac defibrillation in mind, we used a single pulse as well as repetitive extra current with both constant and feedback controlled frequency. We show that turbulence can be terminated using either a resonant modulation of excitability or a resonant extra current. The turbulence is terminated with much higher probability using a resonant frequency perturbation than a nonresonant one. Suppression of the turbulence using a resonant frequency is up to fifty times faster than using a nonresonant frequency, in both the modulation of excitability and the extra current modes. We also demonstrate that resonant perturbation requires strength one order of magnitude lower than that of a single pulse, which is currently used in clinical practice to terminate cardiac fibrillation. Our results provide a robust method of controlling complex chaotic spatiotemporal processes. Resonant drift of spiral waves has been studied extensively in two dimensions, however, these results show for the first time that it also works in three dimensions, despite the complex nature of the scroll wave turbulence. |
7,197 | Alternative presentation of tako-tsubo syndrome with spontaneous echo-contrast and "onion" shaped apical ballooning. | We report the case of a 79-year-old woman with transient left ventricular systolic dysfunction with apical ballooning (tako-tsubo like syndrome, TTS) showing an alternative newly reported "onion" shape. The patient was also characterized by atrial fibrillation and marked spontaneous echo-contrast: possible precipitating role for these conditions in TTS are discussed. |
7,198 | Apparent seizure and atrial fibrillation associated with paliperidone. | A case of apparent seizure and atrial fibrillation associated with paliperidone is reported.</AbstractText>A 46-year-old man arrived at the emergency room (ER) via ambulance. Earlier that morning, his wife observed him awakening in a panic, drifting back to sleep, and then subsequently awakening in a panic with an apparent seizure lasting one to two minutes. The episode included tongue biting and urinary incontinence. His medical history included bipolar disorder, diabetes mellitus, hyperlipidemia, and hypertension. The patient's medications included metformin, insulin glargine, insulin lispro, simvastatin, enalapril, escitalopram, lamotrigine, and clonazepam and had not changed for many months except for the recent addition of paliperidone four days before his arrival at the ER. Electrocardiography revealed atrial fibrillation, a ventricular rate of 151 beats/min, a Q-Tc interval of 461 msec, and no significant changes in the ST segment or T wave. He had no chest pain, and all other laboratory test results and vital signs were normal. The patient was admitted for evaluation and given a single oral dose of potassium chloride. Diltiazem i.v. was administered with resultant conversion to normal sinus rhythm, after which the patient's heart rate and Q-Tc interval normalized. The patient was discharged after one day.</AbstractText>A man taking paliperidone and multiple other drugs experienced atrial fibrillation and a possible seizure. Although these are known adverse effects of atypical antipsychotics, it is unusual to have both events occur concurrently and with low-to-average dosages, and these events have not been associated with paliperidone in published case reports.</AbstractText> |
7,199 | Digoxin and clinical outcomes in systolic heart failure patients on contemporary background heart failure therapy. | Previous trials have shown that digoxin was beneficial in patients with heart failure (HF). However, these studies were conducted before the incorporation of beta blockers as standard therapy for patients with HF. The purpose of this study was to determine the effect of digoxin in patients with HF on a contemporary regimen of renin-angiotensin inhibition and beta blockade. In 347 almost exclusively men, data pertaining to the index hospitalization and occurrence of all-cause mortality or readmission for HF were collected. Cox proportional hazard modeling was used. Patients on digoxin therapy had a lower left ventricular (LV) ejection fraction (EF), higher prevalence of previous hospitalizations for HF and atrial fibrillation, and lower prevalence of hypertension. After adjustment for age, LVEF, history of HF hospitalizations, New York Heart Association class, presence of chronic renal insufficiency, presence of atrial fibrillation, and prescriptions for beta blockers and angiotensin converting enzyme inhibitors or angiotensin receptor blockers, HF hospitalizations (hazard ratio 1.08, 95% confidence interval [CI] 0.77 to 1.50, p = 0.66), total mortality (hazard ratio 1.03, 95% CI 0.78 to 1.35, p = 0.85), or the combined end point of HF hospitalization and total mortality (hazard ratio 1.11, 95% CI 0.81 to 1.53, p = 0.52) were not different in patients using digoxin compared with those not using digoxin. Clinical outcomes were not different in subgroups of patients with EF < or =25%, New York Heart Association class III or IV, atrial fibrillation, heart rate < or =60 beats/min, or patients on beta-blocker therapy. In conclusion, digoxin use was not associated with a decrease in HF hospitalizations or overall mortality rates in a cohort of hospitalized patients with HF with LV systolic dysfunction on contemporary background HF treatment including angiotensin-converting enzyme inhibitors and beta blockers. |
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