Background-Data on the comparative value of the circumferential pulmonary vein and the segmental pulmonary vein ablation for interventional treatment of atrial fibrillation are limited. We hypothesized that the circumferential pulmonary vein ablation approach was superior to the segmental pulmonary vein ablation approach. Methods and Results-One hundred patients with highly symptomatic atrial fibrillation were randomly assigned to undergo either circumferential (nϭ50) or segmental pulmonary vein ablation (nϭ50). Freedom from atrial tachyarrhythmias in a 7-day Holter monitoring at 6 months was the primary end point. Secondary end points were freedom of arrhythmia-related symptoms and a composite of pericardial tamponade, thromboembolic complications, and pulmonary vein stenosis (safety end point). On the basis of the results of the 7-day Holter monitoring at 6 months, 21 patients (42%) after circumferential pulmonary vein ablation and 33 patients (66%) after segmental pulmonary vein ablation (Pϭ0.02) were free of atrial tachyarrhythmia episodes. During the 6-month follow-up period, 27 patients (54%) after circumferential pulmonary vein ablation and 41 patients (82%) after segmental pulmonary vein ablation remained free of arrhythmia-related symptoms (PϽ0.01). No significant difference was found in the safety end point (6 versus 7 events; Pϭ0.77) in the circumferential versus segmental pulmonary vein ablation group, respectively. Conclusions-This study demonstrates no superiority of the circumferential pulmonary vein ablation over segmental pulmonary vein ablation for treatment of atrial fibrillation in terms of efficacy and safety.

Background. Enhanced sympathetic activity at the ventricular myocardium can destabilize repolarization, increasing the risk of death. Sympathetic activity is known to cluster in low-frequency bursts; therefore, we hypothesized that sympathetic activity induces periodic low-frequency changes of repolarization. We developed a technique to assess the sympathetic effect on repolarization and identified periodic components in the low-frequency spectral range (≤0.1 Hz), which we termed periodic repolarization dynamics (PRD). Methods.We investigated the physiological properties of PRD in multiple experimental studies, including a swine model of steady-state ventilation (n = 7) and human studies involving fixed atrial pacing (n = 10), passive head-up tilt testing (n = 11), low-intensity exercise testing (n = 11), and beta blockade (n = 10). We tested the prognostic power of PRD in 908 survivors of acute myocardial infarction (MI). Finally, we tested the predictive values of PRD and T-wave alternans (TWA) in 2,965 patients undergoing clinically indicated exercise testing.Results. PRD was not related to underlying respiratory activity (P < 0.001) or heart-rate variability (P = 0.002). Furthermore, PRD was enhanced by activation of the sympathetic nervous system, and pharmacological blockade of sympathetic nervous system activity suppressed PRD (P ≤ 0.005 for both). Increased PRD was the strongest single risk predictor of 5-year total mortality (hazard ratio 4.75, 95% CI 2.94-7.66; P < 0.001) after acute MI. In patients undergoing exercise testing, the predictive value of PRD was strong and complementary to that of TWA. Conclusion.We have described and identified low-frequency rhythmic modulations of repolarization that are associated with sympathetic activity. Increased PRD can be used as a predictor of mortality in survivors of acute MI and patients undergoing exercise testing.Trial registration. ClinicalTrials.gov NCT00196274.Funding. This study was funded by Angewandte Klinische Forschung, University of Tübingen (252-1-0).

Our findings suggest that RDN is feasible even in cardiac unstable patients. Randomized controlled trials are urgently needed to study the effects of RD in patients with electrical storm and CHF.

We conclude that the implanted DDD-ICD and conventional VVI-ICD are equally safe and effective for therapy of life-threatening ventricular tachyarrhythmias. Although DDD-ICDs allow better rhythm classification, the applied detection algorithms do not offer benefits in avoiding inappropriate therapies during supraventricular tachyarrhythmias.