Background —Atrial fibrillation (AF) can be initiated by ectopic beats originating from the atrial or great venous tissues. This study investigated the anatomic characteristics and electrophysiological properties of pulmonary veins (PVs), as well as the possible mechanisms and response to drugs of ectopic foci, and assessed the effects of radiofrequency (RF) ablation on AF initiated by ectopic beats originating from PVs. Methods and Results —Seventy-nine patients with frequent episodes of paroxysmal AF and 10 control patients were included. Distal PVs showed the shortest effective refractory periods (ERPs), and right superior PVs showed a higher incidence of intra-PV conduction block than left superior PVs. Superior and left PVs had longer myocardial sleeves than inferior and right PVs, respectively. These electrophysiological characteristics were similar between AF and control patients. Propranolol, verapamil, and procainamide suppressed ectopic beats that originated from the PVs. Of 116 ectopic foci that initiated AF, 103 (88.8%) originated from PVs. A mean of 7±3 RF applications completely eliminated 110 ectopic foci (94.8%). During the 6±2-month follow-up period, 68 patients (86.1%) were free of AF without any antiarrhythmic drugs. Follow-up transesophageal echocardiogram showed 42.4% of ablated PVs had focal stenosis. One patient had mild exertional dyspnea after ablation, but it resolved 3 months later; 1 patient had onset of mild exertional dyspnea 5 months after ablation. Conclusions —Electrophysiological characteristics of PVs are different from those in the atria. Ectopic beats from PVs can initiate AF, and β-adrenergic receptor blocker, calcium channel blockers, and sodium channel blockers can suppress these ectopic beats. Careful mapping and elimination of these ectopic foci can cure paroxysmal AF.

Background: Stroke prevention with oral anticoagulants (OACs) is the cornerstone for the management of atrial fibrillation (AF). However, data about the use of OACs among patients ≥90 years of age are limited. We aimed to investigate the risk of ischemic stroke and intracranial hemorrhage (ICH) and the net clinical benefit of OAC treatment for very elderly patients with AF (≥90 years of age). Methods: This study used the National Health Insurance Research Database in Taiwan. Risks of ischemic stroke and ICH were compared between 11 064 and 14 658 patients with and without AF ≥90 years of age without antithrombotic therapy from 1996 to 2011. Patients with AF (n=15 756) were divided into 3 groups (no treatment, antiplatelet agents, and warfarin), and the risks of stroke and ICH were analyzed. The risks of ischemic stroke and ICH were further compared between patients treated with warfarin and nonvitamin K antagonist OACs (NOACs) from 2012 to 2015 when NOACs were available in Taiwan. Results: Compared with patients without AF, patients with AF had an increased risk of ischemic stroke (event number/patient number, incidence = 742/11 064, 5.75%/y versus 1399/14 658, 3.00%/y; hazard ratio, 1.93; 95% confidence interval, 1.74–2.14) and similar risk of ICH (131/11 064, 0.97%/y versus 206/14 658, 0.54%/y; hazard ratio, 0.85; 95% confidence interval, 0.66–1.09) in competing risk analysis for mortality. Among patients with AF, warfarin use was associated with a lower stroke risk (39/617, 3.83%/y versus 742/11 064, 5.75%/y; hazard ratio, 0.69; 95% confidence interval, 0.49–0.96 in a competing risk model), with no difference in ICH risk compared with nontreatment. When compared with no antithrombotic therapy or antiplatelet drugs, warfarin was associated with a positive net clinical benefit. These findings persisted in propensity-matched analyses. Compared with warfarin, NOACs were associated with a lower risk of ICH (4/978, 0.42%/y versus 19/768, 1.63%/y; hazard ratio, 0.32; 95% confidence interval, 0.10–0.97 in a competing risk model), with no difference in risk of ischemic stroke. Conclusions: Among patients with AF ≥90 years of age, warfarin was associated with a lower risk of ischemic stroke and positive net clinical benefit. Compared with warfarin, NOACs were associated with a lower risk of ICH. Thus, OACs may still be considered as thromboprophylaxis for elderly patients, with NOACs being the more favorable choice.

Background: Catheter ablation as first-line therapy for ventricular tachycardia (VT) at the time of implantable cardioverter defibrillator (ICD) implantation has not been adopted into clinical guidelines. Also, there is an unmet clinical need to prospectively examine the role of VT ablation in patients with nonischemic cardiomyopathy, an increasingly prevalent population that is referred for advanced therapies globally. Methods: We conducted an international, multicenter, randomized controlled trial enrolling 180 patients with cardiomyopathy and monomorphic VT with an indication for ICD implantation to assess the role of early, first-line ablation therapy. A total of 121 patients were randomly assigned (1:1) to ablation plus an ICD versus conventional medical therapy plus an ICD. Patients who refused ICD (n=47) were followed in a prospective registry after stand-alone ablation treatment. The primary outcome was a composite end point of VT recurrence, cardiovascular hospitalization, or death. Results: Randomly assigned patients had a mean age of 55 years (interquartile range, 46–64) and left ventricular ejection fraction of 40% (interquartile range, 30%–49%); 81% were male. The underlying heart disease was ischemic cardiomyopathy in 35%, nonischemic cardiomyopathy in 30%, and arrhythmogenic cardiomyopathy in 35%. Ablation was performed a median of 2 days before ICD implantation (interquartile range, 5 days before to 14 days after). At 31 months, the primary outcome occurred in 49.3% of the ablation group and 65.5% in the control group (hazard ratio, 0.58 [95% CI, 0.35–0.96]; P =0.04). The observed difference was driven by a reduction in VT recurrence in the ablation arm (hazard ratio, 0.51 [95%CI, 0.29–0.90]; P =0.02). A statistically significant reduction in both ICD shocks (10.0% versus 24.6%; P =0.03) and antitachycardia pacing (16.2% versus 32.8%; P =0.04) was observed in patients who underwent ablation compared with control. No differences in cardiovascular hospitalization (32.0% versus. 33.7%; hazard ratio, 0.82 [95% CI, 0.43–1.56]; P =0.55) or mortality (8.9% versus 8.8%; hazard ratio, 1.40 [95% CI, 0.38–5.22]; P =0.62]) were observed. Ablation-related complications occurred in 8.3% of patients. Conclusions: Among patients with cardiomyopathy of varied causes, early catheter ablation performed at the time of ICD implantation significantly reduced the composite primary outcome of VT recurrence, cardiovascular hospitalization, or death. These findings were driven by a reduction in ICD therapies. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02848781.