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Background: Pulsed field ablation (PFA) is a novel form of ablation using electrical fields to ablate cardiac tissue. There are only limited data assessing the feasibility and safety of this type of ablation in humans., Methods: PULSED AF (Pulsed Field Ablation to Irreversibly Electroporate Tissue and Treat AF; https://www.clinicaltrials.gov; unique identifier: NCT04198701) is a nonrandomized, prospective, multicenter, global, premarket clinical study. The first-in-human pilot phase evaluated the feasibility and efficacy of pulmonary vein isolation using a novel PFA system delivering bipolar, biphasic electrical fields through a circular multielectrode array catheter (PulseSelect; Medtronic, Inc). Thirty-eight patients with paroxysmal or persistent atrial fibrillation were treated in 6 centers in Australia, Canada, the United States, and the Netherlands. The primary outcomes were ability to achieve acute pulmonary vein isolation intraprocedurally and safety at 30 days., Results: Acute electrical isolation was achieved in 100% of pulmonary veins (n=152) in the 38 patients. Skin-to-skin procedure time was 160±91 minutes, left atrial dwell time was 82±35 minutes, and fluoroscopy time was 28±9 minutes. No serious adverse events related to the PFA system occurred in the 30-day follow-up including phrenic nerve injury, esophageal injury, stroke, or death., Conclusions: In this first-in-human clinical study, 100% pulmonary vein isolation was achieved using only PFA with no PFA system-related serious adverse events. Graphic Abstract: A graphic abstract is available for this article.

Background: Early recurrence of atrial tachyarrhythmia (ERAT) is common after pulmonary vein isolation (PVI) and has been associated with an increased risk of late atrial fibrillation (AF) recurrence., Objective: The purpose of this study was to determine the incidence and outcomes of patients experiencing ERAT after PVI using advanced-generation ablation technologies., Methods: This is a prespecified substudy of the CIRCA-DOSE (Cryoballoon vs Irrigated Radiofrequency Catheter Ablation: Double-Short vs Standard Exposure Duration) trial, a prospective, randomized, multicenter study comparing PVI with contact force-guided radiofrequency ablation to secondary-generation cryoballoon ablation for paroxysmal AF. All study patients received an implantable cardiac monitor to allow continuous rhythm monitoring. ERAT was defined as any recurrent atrial tachyarrhythmia within the first 90 days after AF ablation., Results: ERAT occurred in 61% of the 346 patients at a median of 12 days (range 1-90 days) after ablation. ERAF was a significant predictor of late recurrence (60.1% with ER vs 25.9% without ER; P <.001) and symptomatic atrial tachyarrhythmia (31.6% with ERAF vs 6.7% without ERAF; P <.001). Receiver operating curve analyses revealed a strong correlation between ERAT timing and burden and late recurrence. Multivariate analysis identified ER timing (hazard ratio [HR] 2.90; 95% confidence interval [CI] 1.41-5.95; P = .004) and burden (HR 1.05 per 1% ER burden; 95% CI 1.04-1.07; P <.001) as strong independent predictors of late recurrence. Incidence rate, timing, burden, and prognostic significance of ER did not differ between the study groups., Conclusion: ERAT remains common after PVI despite use of advanced-generation ablation technologies. Early AF recurrence beyond 3 weeks after ablation is associated with increased risk of late recurrence., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: This study compared generalized complex fractionated atrial electrograms (CFAE) ablation versus a selective CFAE ablation strategy targeting areas of continuous electric activity., Methods and Results: Subjects with symptomatic, persistent/high-burden paroxysmal atrial fibrillation (AF) were enrolled at 6 centers (n=86) and randomized to 1 of 2 arms. For group I, all CFAE regions with an interval confidence level >7 were ablated followed by pulmonary vein isolation (PVI). For group II, only CFAE sites with continuous electric activity were ablated followed by PVI. For PVI, all 4 PV antra were isolated with confirmed entrance block. Subjects were followed for 1 year with a visit, ECG, and 48-hour Holter every 3 months. Symptoms were confirmed by loop recording. The primary end point was freedom from arrhythmia >30 seconds at 1 year. For both group I and II, CFAE ablation prolonged AF cycle length (25±33 versus 23±33 ms; P=0.78) and resulted in similar rates of AF termination (37% versus 28%; P=0.42). Radiofrequency duration during CFAE ablation was significantly less in group II (23±20 versus 38±20 minutes; P=0.002). At 1-year follow-up, freedom from AF/atrial flutter/atrial tachycardia recurrence was significantly higher in group I versus group II after 1 procedure (50% versus 28%; P=0.03). There were also significantly fewer repeat procedures in group I (13% versus 36%; P=0.021)., Conclusions: Continuous electric activity ablation+PVI result in a similar incidence of acute AF termination with significantly less radiofrequency time. However, incidence of repeat procedures and long-term recurrence of AF/atrial flutter/atrial tachycardia are significantly lower using generalized CFAE ablation+PVI. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00926783.

Background: Systemic thromboembolism and bleeding remain the two most common and serious complications of catheter ablation of atrial fibrillation. A variety of periprocedure anticoagulation strategies have been proposed to mitigate these risks. Although operators are now routinely administering dabigatran for anticoagulation in this setting, its relative safety and effectiveness compared to warfarin are unknown., Methods and Results: A total of 202 patients received dabigatran as part of their periprocedural anticoagulation regimen at the time of initial or redo catheter ablation for symptomatic atrial fibrillation. A comparison group of 202 patients treated with warfarin was randomly selected from patients undergoing atrial fibrillation (AF) ablation during the same time period. AF types were paroxysmal in 223 patients, persistent in 158 patients, and longstanding persistent in 13 patients. Mean age was 60.0 ± 10.5 years, 55 % had a history of hypertension, and mean CHADS-VASc score was 1.7 ± 1.3. "Continuous" warfarin or dabigatran was administered in 80 and 32 % of patients, respectively. Time to first dose of dabigatran post-procedure was 12.2 ± 10.3 h. Two dabigatran and no warfarin-treated patients had systemic thromboembolism (p = NS); five dabigatran and three warfarin-treated patients had bleeding complications (p = NS, combined endpoint p = 0.116). One dabigatran patient had severe pericardial bleeding (3 L blood loss)., Conclusions: In a retrospective pilot trial comparing the risks of systemic thromboembolism or bleeding complications in patients treated with warfarin or dabigatran anticoagulation, the outcomes were similar. A prospective trial is warranted.

Background: Prior reports on patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) focused on individuals with advanced forms of the disease. Data on the diagnostic performance of various testing modalities in newly identified individuals suspected of having ARVC/D are limited., Objective: The purpose of the Multidisciplinary Study of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia was to study the clinical characteristics and diagnostic evaluation of a large group of patients newly identified with ARVC/D., Methods: A total of 108 newly diagnosed patients with suspected ARVC/D were prospectively enrolled in the United States and Canada. The patients underwent noninvasive and invasive tests using standardized protocols that initially were interpreted by the enrolling center and adjudicated by blind analysis in six core laboratories. Patients were followed for a mean of 27 +/- 16 months (range 0.2-63 months)., Results: The clinical profile of these newly diagnosed patients differs from the profile of reported patients with more advanced disease. There was considerable difference in the initial and final classification of the presence of ARVC/D after the diagnostic tests were evaluated by the core laboratories. Final clinical diagnosis was 73 affected, 28 borderline, and 7 unaffected. Individual tests agreed with the final diagnosis in 50% to 70% of the 73 patients with a final classification of affected., Conclusion: The clinical profile of 108 newly diagnosed probands with suspected ARVC/D indicates that a combination of diagnostic tests is needed to evaluate the presence of right ventricular structural, functional, and electrical abnormalities. Echocardiography, right ventricular angiography, signal-averaged ECG, and Holter monitoring provide optimal clinical evaluation of patients suspected of ARVC/D.