Adelqui Peralta

Regular physical activity and risk of atrial fibrillation: a systematic review and meta-analysis.

Background— Although previous studies have suggested that competitive athletes have a higher risk of atrial fibrillation than the general population, limited and inconsistent data are available on the association between regular physical activity and the risk of atrial fibrillation. Methods and Results— A systematic, comprehensive literature search was performed using MEDLINE, EMBASE, and COCHRANE until 2011. Extracted data from the eligible studies were meta-analyzed using fixed effects model. Four studies, which included 95 526 subjects, were eligible for meta-analysis. For all of the studies included, the extreme groups (ie, maximum versus minimal amount of physical activity) were used for the current analyses. The total number of participants belonging to the extreme groups was 43 672. The pooled odds ratio (95% confidence interval) for atrial fibrillation among regular exercisers was 1.08 (0.97–1.21). Conclusions— Our data do not support a statistically significant association between regular physical activity and increased incidence of atrial fibrillation.Background—Although previous studies have suggested that competitive athletes have a higher risk of atrial fibrillation than the general population, limited and inconsistent data are available on the association between regular physical activity and the risk of atrial fibrillation. Methods and Results—A systematic, comprehensive literature search was performed using MEDLINE, EMBASE, and COCHRANE until 2011. Extracted data from the eligible studies were meta-analyzed using fixed effects model. Four studies, which included 95 526 subjects, were eligible for meta-analysis. For all of the studies included, the extreme groups (ie, maximum versus minimal amount of physical activity) were used for the current analyses. The total number of participants belonging to the extreme groups was 43 672. The pooled odds ratio (95% confidence interval) for atrial fibrillation among regular exercisers was 1.08 (0.97–1.21). Conclusions—Our data do not support a statistically significant association between regular physical activity and increased incidence of atrial fibrillation.

The class III antiarrhythmic effect of sotalol exerts a reverse use-dependent positive inotropic effect in the intact canine heart.

OBJECTIVES We sought to study the rate related effects of sotalol on myocardial contractility and to test the hypothesis that the class III antiarrhythmic effect of sotalol has a reverse use-dependent positive inotropic effect in the intact heart. BACKGROUND Antiarrhythmic drugs exert significant negative inotropic effects. Sotalol, a beta-adrenergic blocking agent with class III antiarrhythmic properties, may augment contractility by virtue of its ability to prolong the action potential duration (APD). METHODS In 10 anesthetized dogs, measurements of left ventricle (LV) peak (+)dP/dt and simultaneous endocardial action potentials were made during baseline conditions and after sequential administration of esmolol and sotalol. In addition, electrical and mechanical restitution curves were constructed at a basic pacing cycle length of 600 ms by introducing a test pulse of altered cycle length ranging from 200 ms to 2,000 ms. RESULTS In the steady state pacing experiments, sotalol prolonged the APD in a reverse use-dependent manner; such an effect was not seen with esmolol. At cycle lengths exceeding 400 ms, LV (+)dP/dt was significantly higher with sotalol than it was with esmolol. There was a direct relation between APD and LV (+)dP/dt with sotalol (r = 0.46, p < 0.001), but there was no significant relation between APD and LV (+)dP/dt with esmolol (r = 0.27, p = NS). Results in the single beat (restitution) studies were qualitatively similar to the steady state results; APD (at cycle length >400 ms) and LV (+)dP/dt (at cycle length >600 ms) were significantly higher with sotalol than they were with esmolol. CONCLUSIONS The reverse use-dependent prolongation of APD by sotalol is associated with a positive inotropic effect.

Pacing system malfunction is a rare cause of hospital admission for syncope in patients with a permanent pacemaker.

Few studies have examined the prevalence of permanent pacemaker (PPM) malfunction among patients with a previously implanted pacemaker admitted to the hospital with syncope.

Undersensing of Ventricular Fibrillation in a Noncommitted Nonthoracotomy Cardioverter Defibrillator System

Objective: Evaluation of the impact of undersensing on VF detection time and the relationship of undersensing to the programmed shock energy. Background: Failure to reconfirm an ongoing arrhythmia due to undersensing by a noncommitted ICD might prolong the time to therapy. Methods: We measured initial detection times and redetection times at predischarge and at 2 and 6 months in 29 patients (22 men, mean age 60 years) with a noncommitted nonthoracotomy ICD. Telemetry data and output markers were used to analyze each induction. Results: Undersensing hading to failure to reconfirm was present in 44 (11.1%) of 398 episodes of sustained VF and prolonged significantly the median initial detection time from 2.3 seconds (25th and 75th percentiles: 2 and 2.6 s, respectively) to 5.45 seconds (4.3 and 7.35 s. P < 0.0001). One episode required external defibrillation after reconfirmation failure occurred during charging; the total detection time prior to shock was 46 seconds. In a subset of 87 episodes with failed first shocks, the initial detection time was 2.3 seconds (2.1 and 2.8 s) and the redetection time 3 seconds (2.5 and 4.77 s. P < 0.0001). The presence of undersensing prolonged the redetection from 2.6 seconds (2.35 and 3.1 s) to 5.4 seconds (4.53 and 7.35 s, P < 0.0001). Undersensing was more prevalent during the redetection period (P = 0.004) and in episodes of sustained VF in which the first shock energy was higher than 15 f (19.7% vs 5.8%, P < 0.0001). Conclusions: In this automatic defibriliator system, undersensing occurs in 11% of the sustained VF inductions and prolongs detection time significantly. Redetection is longer than initial detection mostly due to the presence of undersensing, the frequency of which is proportional to the programmed energy. The clinical significance of this finding is unknown.

Possible Proarrhythmia with Dronedarone

Possible Proarrhythmia with Dronedarone JONATHAN ROSMAN, M.D.,∗ PETER HOFFMEISTER, M.D.,† MATTHEW REYNOLDS, M.D.,‡ and ADELQUI PERALTA, M.D., F.H.R.S., C.C.D.S.‡ From the ∗Cardiac Arrhythmia Service, Boca Raton, Florida; †Department of Cardiac Electrophysiology, West Roxbury VA Hospital, Boston University, Boston, Massachusetts; and ‡Department of Cardiac Electrophysiology, West Roxbury VA Hospital, Harvard University, Boston, Massachusetts, USA

Unusual QRS Morphology on ECG: A Rare Condition and an Interesting Response to Pacing

We present the interesting case of a young man with borderline wide QRS complexes noted on electrocardiogram (ECG). The diagnosis of an unusual form of preexcitation was reached using observations from intracardiac tracings at electrophysiology study. Atrial pacing consistently resulted in further widening of the first conducted QRS complex, and the physiology underlying this unusual finding is explored.

Posttraumatic stress disorder and mortality in VA patients with implantable cardioverter‐defibrillators

The association between posttraumatic stress disorder (PTSD) and mortality in patients undergoing implantable cardioverter‐defibrillator (ICD) placement has not been evaluated in US veterans.

Regular Physical Activity and Risk of Atrial FibrillationClinical Perspective

Background— Although previous studies have suggested that competitive athletes have a higher risk of atrial fibrillation than the general population, limited and inconsistent data are available on the association between regular physical activity and the risk of atrial fibrillation. Methods and Results— A systematic, comprehensive literature search was performed using MEDLINE, EMBASE, and COCHRANE until 2011. Extracted data from the eligible studies were meta-analyzed using fixed effects model. Four studies, which included 95 526 subjects, were eligible for meta-analysis. For all of the studies included, the extreme groups (ie, maximum versus minimal amount of physical activity) were used for the current analyses. The total number of participants belonging to the extreme groups was 43 672. The pooled odds ratio (95% confidence interval) for atrial fibrillation among regular exercisers was 1.08 (0.97–1.21). Conclusions— Our data do not support a statistically significant association between regular physical activity and increased incidence of atrial fibrillation.Background—Although previous studies have suggested that competitive athletes have a higher risk of atrial fibrillation than the general population, limited and inconsistent data are available on the association between regular physical activity and the risk of atrial fibrillation. Methods and Results—A systematic, comprehensive literature search was performed using MEDLINE, EMBASE, and COCHRANE until 2011. Extracted data from the eligible studies were meta-analyzed using fixed effects model. Four studies, which included 95 526 subjects, were eligible for meta-analysis. For all of the studies included, the extreme groups (ie, maximum versus minimal amount of physical activity) were used for the current analyses. The total number of participants belonging to the extreme groups was 43 672. The pooled odds ratio (95% confidence interval) for atrial fibrillation among regular exercisers was 1.08 (0.97–1.21). Conclusions—Our data do not support a statistically significant association between regular physical activity and increased incidence of atrial fibrillation.

Regular Physical Activity and Risk of Atrial FibrillationClinical Perspective: A Systematic Review and Meta-analysis

Background— Although previous studies have suggested that competitive athletes have a higher risk of atrial fibrillation than the general population, limited and inconsistent data are available on the association between regular physical activity and the risk of atrial fibrillation. Methods and Results— A systematic, comprehensive literature search was performed using MEDLINE, EMBASE, and COCHRANE until 2011. Extracted data from the eligible studies were meta-analyzed using fixed effects model. Four studies, which included 95 526 subjects, were eligible for meta-analysis. For all of the studies included, the extreme groups (ie, maximum versus minimal amount of physical activity) were used for the current analyses. The total number of participants belonging to the extreme groups was 43 672. The pooled odds ratio (95% confidence interval) for atrial fibrillation among regular exercisers was 1.08 (0.97–1.21). Conclusions— Our data do not support a statistically significant association between regular physical activity and increased incidence of atrial fibrillation.Background—Although previous studies have suggested that competitive athletes have a higher risk of atrial fibrillation than the general population, limited and inconsistent data are available on the association between regular physical activity and the risk of atrial fibrillation. Methods and Results—A systematic, comprehensive literature search was performed using MEDLINE, EMBASE, and COCHRANE until 2011. Extracted data from the eligible studies were meta-analyzed using fixed effects model. Four studies, which included 95 526 subjects, were eligible for meta-analysis. For all of the studies included, the extreme groups (ie, maximum versus minimal amount of physical activity) were used for the current analyses. The total number of participants belonging to the extreme groups was 43 672. The pooled odds ratio (95% confidence interval) for atrial fibrillation among regular exercisers was 1.08 (0.97–1.21). Conclusions—Our data do not support a statistically significant association between regular physical activity and increased incidence of atrial fibrillation.