Introduction
Durable pulmonary vein isolation is the determinant of the outcome in patients with atrial fibrillation (AF) after catheter ablation[1-3]. Pulmonary vein reconnection (PVR) has been considered as a major reason for AF recurrence after index ablation[4-5]. Therefore, an observation period in the index procedure was usually given for identification of acute PVR and minimizing the possibility of repeat ablation. However, the detailed conduction property at reconnection sites has not been sufficiently investigated.
Presence of epicardial musculature connecting distal PVs and the atrium is common as the wall of the atrium can be uneven in thickness with bilayer architecture found in a large area[6,7]. Epicardial connection has been recently described as a cause of failed first-pass isolation[8-11]. It can also be observed in the reconnected PVs during the waiting period, which requires treatment but lacks description and exploration including its related ablation parameters.
In this study, we aimed to understand the role of acute epicardial PVR (AEPVR) and its influencing factors by investigating its prevalence, locations, electrogram (EGM) characteristics and related lesion set parameters, which were compared to endocardial gap as well as the epicardial PVR found in repeat procedures.