Importance of the relative epicardial connection locations and right-sided pulmonary vein isolation line for successful pulmonary vein isolation

Background: The presence of an epicardial connection (EC) decreases the success rate of pulmonary vein isolation (PVI); however, the effect of designing isolation lines has not been evaluated. Objective: We sought to clarify the effects of designing an anterior line for right-sided PVI considering the presence and location of the EC. Methods: Seventy-four consecutive patients who underwent initial catheter ablation for atrial fibrillation were retrospectively included in this study. The presence of the EC was determined by the left atrial (LA) activation map during right atrial pacing, and patients were divided into EC-positive (n=23, 31%) and EC-negative (n=51, 69%) groups. EC-positive patients were further subdivided based on the EC location: on-the-line group, (EC on the PVI line, n=11); inside-line group (EC on the pulmonary vein [PV] side, n=10); and outside-line group (EC on the LA side, n=2). The PVI parameters were compared among the three groups. Results: The success rates of the first-pass isolation were comparable between the EC-negative and EC-positive groups (70.6% vs. 60.9%, ns), but the success rate was significantly higher in the on-the-line group than in the inside-line group (91% vs. 20%, p=0.002). First-pass isolation was successful in both patients in the outside-line group. Additional carina ablation was required only in the inside-line group. Conclusions: The association between the EC site and the right-sided PV anterior isolation line affected the success rate of first-pass isolation. For successful right-sided PVI, it is important to consider the EC site when designing the PVI line.