Left atrial substrate modification for persistent atrial fibrillation and left atrial macro or microreentrant tachycardia using a single-shot pulsed field ablation system - a single centre case series

Abstract Background Pulsed field ablation (PFA) is a novel ablation technique for pulmonary vein isolation (PVI) in patients with paroxysmal and persistent atrial fibrillation. However, data for efficacy and safety of PFA for left atrial substrate modification in patients with long-standing persistent atrial fibrillation (AF) and macro- as well as microreentrant atrial tachycardia (AT) is scarce. Aim Here we provide a retrospective, single-centre case series regarding efficacy and safety of left atrial substrate modification, using a single-shot PFA system. Methods and Results Over a period of 6 months, 8 patients with long-standing persistent AF and AT underwent Re-PVI with left atrial substrate modification using a single-shot PFA system. Median age was 63 years (IQR 58 - 75), and 4/8 of patients were female. Time from first diagnosis of AF was 7 years (IQR 4 –10). All but 1 patient underwent previous PVI (IQR 1-3) with (5/7) or without (2/7) prior substrate modification using radiofrequency ablation. On transthoracic echocardiography, all patients showed severe left- and right-atrial enlargement, with LA volume of 58 ml/m2 (IQR 49.7–72) and RA diameter of 62 mm (IQR 55-75). In 8 patients, 9 ATs and 2 typical flutters were treated with PFA. Following PVI, additional posterior wall isolation was performed in 6/8 patients, roof in 6/8, and anterior wall (between superior mitral anulus and RSPV) in 4/8 patients. In addition, 2/8 patients had cavotricuspid isthmus ablation for typical atrial flutter. All patients received atropine prior to PVI, as well as bolus of nitro-glycerine prior to PFA of anterior wall and/or cavotricuspid isthmus. Acute success rate was 100% and all ATs as well as typical flutter terminated with PFA. After median follow-up time of 88 days (IQR 61-112), 3 patients had a documented recurrence of AF/AT, in 2 of which electrical cardioversion was necessary. We observed no acute and/or chronic complications following PFA, i.e. no pericardial effusion/tamponade, TIA/stroke, myocardial infarction, coronary artery spasm, AV-block, bleeding, or atrioesophageal fistula. Conclusion In this small, single-centre case series, left atrial substrate modification for long-standing persistent AF and AT using a single-shot PFA system was safe and showed an excellent acute success rate.