Organization of atrial fibrillation during pulsed field ablation

Abstract Background Pulse Field Ablation (PFA) has been acknowledged as an effective and safe tool for ablation of Atrial Fibrillation (AF). It is known that during AF ablation, the arrhythmia may organize into atrial flutter. The left atrial posterior wall is identified as a critical source of non-Pulmonary Vein (PV) triggers that facilitate maintenance of atrial fibrillation. Objective The purpose of this study is to investigate the phenomenon of atrial flutter organization from AF during the application of PFA. Methods This prospective multicentric study encompasses 248 consecutive patients with persistent AF across American and European institutions, undergoing first time catheter ablation. All receive isolation of the Pulmonary Veins (PV) plus Posterior Wall (PW) isolation. The PW isolation procedure targeted the standard area between the PVs and extended to the area demarcated by the line connecting the inferior borders of the inferior PV-encircling lesions to the coronary sinus defined lower part of PW (Fig. 1). The study documented the specific locations where AF organized into atrial flutter with a stable cycle length during PFA. Results Organization of AF to atrial flutter during PFA was observed in 156 (62.9%) patients. Analysis of the organization of flutter revealed that in 86 (55.1%) of these cases, flutter began while ablating the lower part of the PW. Moreover, 17 (10.9%) initiated while ablating the PVs, and 53 (33.9%) during the ablation of the central part of posterior wall (Fig.1). Notably, flutter were described as perimitral in 73 (46.8%), as typical in 49 (31.4%), and as roof-dependent in 34 (21.8%) of cases (Fig.2). Conclusion The findings underscore that during PFA for AF, there is a pronounced tendency for the arrhythmia to organize into atrial flutter, particularly during the ablation of the lower posterior wall. Notably ablation in the left atrium organized AF in typical atrial flutter at a considerable rate.Fig.1 Fig.2