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[Figure: see text]. [ABSTRACT FROM AUTHOR]

Background: Whether adding cardiac resynchronization therapy (CRT-D) to an implanted cardioverter-defibrillator alters the risk of atrial fibrillation or other atrial tachyarrhythmias (AF/AT), or if postimplantation AF/AT modulate the benefits of CRT-D, remain unknown.Methods and Results: We studied 972 Resynchronization/Defibrillation in Ambulatory Heart Failure Trial (RAFT) participants without permanent AF, who were randomized to CRT-D (n=495) versus nonresynchronization defibrillator (implanted cardioverter-defibrillator; n=477) within the predefined stratum eligible for an atrial lead. Occurrence of postrandomization AF/AT was prospectively assessed, and Cox models were used to test the independent association between the postrandomization AF/AT and the RAFT primary composite outcome of all-cause mortality or hospitalization for heart failure. Over 41 (±19) months, postrandomization AF/AT occurred in 216 (45.3%) patients randomized to implanted cardioverter-defibrillator and 249 (50.3%) randomized to CRT-D. After adjusting for competing risk of death, randomization to CRT-D increased risk of postrandomization AF/AT (hazard ratio, 1.20; 95% confidence interval, 1.00-1.42; P=0.045). Postrandomization AF/AT, which remained paroxysmal in 69.5%, did not reduce biventricular pacing percentage. In adjusted models, postrandomization AF/AT was not associated with the primary outcome (hazard ratio, 1.04; 95% confidence interval, 0.84-1.30). However, AF/AT was associated with a borderline decreased risk of mortality (hazard ratio, 0.75; 95% confidence interval, 0.58-1.00) but increased risk of heart failure hospitalization (hazard ratio, 1.43; 95% confidence interval, 1.08-1.90).Conclusions: In RAFT, nearly half of the patients developed postrandomization AF/AT, and those randomized to CRT-D had borderline significant higher risk. Postrandomization AF/AT was associated with risk of heart failure hospitalization, but not with the primary composite outcome.Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00251251. [ABSTRACT FROM AUTHOR]

Background: This study aimed to determine 5-year efficacy of catheter ablation for persistent atrial fibrillation (AF) using AF termination as a procedural end point.Methods and Results: One hundred fifty patients (57±10 years) underwent persistent AF ablation using a stepwise ablation approach (pulmonary vein isolation, electrogram-guided, and linear ablation) with the desired procedural end point being AF termination. Repeat ablation was performed for recurrent AF or atrial tachycardia. AF was terminated by ablation in 120 patients (80%). Arrhythmia-free survival rates after a single procedure were 35.3%±3.9%, 28.0%±3.7%, and 16.8%±3.2% at 1, 2, and 5 years, respectively. Arrhythmia-free survival rates after the last procedure (mean 2.1±1.0 procedures) were 89.7%±2.5%, 79.8%±3.4%, and 62.9%±4.5%, at 1, 2, and 5 years, respectively. During a median follow-up of 58 (interquartile range, 43-73) months after the last ablation procedure, 97 of 150 (64.7%) patients remained in sinus rhythm without antiarrhythmic drugs. Another 14 (9.3%) patients maintained sinus rhythm after reinitiation of antiarrhythmic drugs, and an additional 15 (10.0%) patients regressed to paroxysmal recurrences only. Failure to terminate AF during the index procedure (hazard ratio 3.831; 95% confidence interval, 2.070-7.143; P<0.001), left atrial diameter≥50 mm (hazard ratio 2.083; 95% confidence interval, 1.078-4.016; P=0.03), continuous AF duration≥18 months (hazard ratio 1.984; 95% confidence interval, 1.024-3.846; P<0.04), and structural heart disease (hazard ratio 1.874; 95% confidence interval, 1.037-3.388; P=0.04) predicted arrhythmia recurrence.Conclusions: In patients with persistent AF, an ablation strategy aiming at AF termination is associated with freedom from arrhythmia recurrence in the majority of patients over a 5-year follow-up period. Procedural AF nontermination and specific baseline factors predict long-term outcome after ablation. [ABSTRACT FROM AUTHOR]

The article seeks to understand clinically encountered pitfalls in the assessment of transmitral conduction block using differential coronary sinus and appendage pacing techniques in patients with left mitral isthmus linear ablation. It concludes that every fifth assessment of bidirectional block across mitral isthmus linear lesion encountered a pitfall. The article suggests that recognition of pitfall during the procedure is feasible and necessitates distinction of far-field left atrium.

The article explores the impact of complex fractionated atrial electrograms (CFAE) activation direction and rate on electrogram (EGM) fractionation using left atrial high-density mapping. EGM fractionation was found in a minority of continuous CFAE sites in sinus rhythm (SR) and coronary sinus pacing (CSp) rhythm. Using activation maps in SR and CSp, the authors found that 71% of EGM fractionation was caused by wave collision and 24% was caused by regional slow conduction.