A high degree of success was observed in this cohort of primarily longstanding persistent AF patients treated for recurrent AF with FIRM-guided rotor ablation. Prospective randomized controlled trials are needed.

Introduction Ablation index (AI)‐guided ablation according to the CLOSE protocol is very effective in terms of chronic pulmonary vein isolation (PVI). However, the optimal radiofrequency (RF) power remains controversial. Here, we thought to investigate the efficiency and safety of an AI‐guided fixed circumferential 50 W high‐power short‐duration (HPSD) PVI using the CLOSE protocol. Methods and Results In a single‐center trial, 40 patients underwent randomized PVI using AI‐guided ablation without esophageal temperature monitoring. In 20 patients a CLOSE protocol guided fixed 50 W HPSD was followed irrespective of the anatomical localization. Twenty subjects were treated according to the CLOSE protocol with standard power settings (20 W posterior and 40 W roof and anterior wall). In addition, 80 consecutive patients were treated according to the HPSD protocol to gather additional safety data. All patients underwent postprocedural esophagogastroduodenoscopy to reveal esophageal lesions (EDELs). The mean total procedural time was 80.3 ± 22.5 in HPSD compared to control 109.1 ± 27.4 min (p < .001). The total RF‐time was significantly lower in HPSD with 1379 ± 505 s versus control 2374 ± 619 s (p < .001). There were no differences in periprocedural complications. EDEL occurred in 13% in the HPSD and 10% in the control group. EDEL occurring in the 50 W HSDP patients were smaller, more superficial, and had a faster healing tendency. Conclusion A fixed 50 W HPSD circumferential PVI relying on the AI and CLOSE protocol reduce the total procedure time and the total RF time, without increasing the complication rates. The incidence of EDELs was similar using 50 W at the posterior atrial wall.

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Introduction Ablation of atrial fibrillation (AF) with high‐power‐short‐duration (HPSD) radiofrequency (RF) technology is emerging as a new standard of care in many electrophysiology laboratories. While procedural short‐term efficacy and efficiency is very promising, little is known about mid‐ to long‐term effects of HPSD ablation for pulmonary vein isolation (PVI) and left atrial substrate modification. Methods In a single‐center registry, 412 AF procedures were performed in 400 individual patients using a standardized CLOSE protocol‐guided fixed 50 W HPSD ablation, aiming for an ablation index (AI) of 400 on the posterior and 550 on the anterior wall. Additional substrate‐tailored lines were performed when required. Results After a mean clinical follow‐up of 337 ± 134 days, 15 patients suffered from AF recurrence beyond the blinding period. Twelve gave consent to the indicated reablation. Here, 11 of 12 patients had chronic isolation of all four pulmonary veins (PV). In three of six patients, a reconnection of additional left atrial ablation lines was revealed. Ten out of 12 patients showed progressive fibrous atrial cardiomyopathy and required additional left atrial substrate modification or reisolation of left‐atrial lines. During the follow‐up no clinical case of atrioesophageal fistula was registered. No PV stenosis after initial HPSD PVI was documented. Conclusions Patients requiring reablation of AF or other atrial tachycardia after a fixed 50 W HPSD circumferential PVI and substrate modification predominantly suffer from progressive fibrous atrial cardiomyopathy, while PV reconnection appears to be a rare cause of AF recurrence.