Catheter Ablation Approach Targeting Epicardial Connections to the Right Pulmonary Vein Antrum Detected before Pulmonary Vein Isolation

Abstract

ABSTRACTBackgroundEpicardial connections from surrounding structures to the right pulmonary vein (PV) antrum impede the PV isolation. This study aimed to evaluate the efficacy of an ablation approach targeting epicardial connections for right PV isolations.MethodsWe prospectively enrolled 124 atrial fibrillation patients who underwent initial PV isolations. We identified the activation breakthrough site into the right PV antrum (BT-RPV) on the activation map created during high right atrial pacing before the PV isolation. BT-RPV sites were targeted when right PV isolations were not achieved by a wide antral circumferential ablation (WACA).ResultsA BT-RPV was observed in 83 cases (67%). BT-RPV sites were predominantly located on the anterior part of the carina (45% of BT-RPV sites). PV isolation was achieved by a WACA in all 41 cases without BT-RPVs. Among the cases with BT-RPVs, the PV isolation was achieved by a WACA in all 48 cases where all BT-RPV sites were covered by the PV isolation line. Conversely, the PV isolation was completed by a WACA in only 5 out of 35 cases (14%) when not all BT-RPV sites were covered. In 30 cases where the WACA did not achieve the PV isolation, 35 sites were targeted for the BT-RPV ablation. The initial BT-RPV ablation led to a PV isolation at 20 sites, while the remaining 15 BT-RPV sites required a repeat BT-RPV ablation. The ablated area of a successful BT-RPV ablation was 0.9 [0.6–1.2] cm2, corresponding to the area activated within 15 [14-16] ms after the BT-RPV emergence. Ablating the area that was activated within 14 ms after the BT-RPV emergence was associated with successful PV isolations (sensitivity 91% and specificity 100%).ConclusionAblation targeting BT-RPV sites is effective for a right PV isolation. However, an extensive ablation area is required to eliminate BT-RPVs.CLINICAL PERSPECTIVEWhat is Known?Pulmonary vein isolation using a wide antral circumferential ablation is sometimes complicated by epicardial connections from neighboring structures to the right pulmonary vein antrum.The intercaval muscular fibers and septopulmonary bundle can act as substrates for epicardial conduction pathways.What the Study AddsEpicardial connections to the right pulmonary vein antrum have been identified in 67% of patients with atrial fibrillation.Targeted ablation at activation breakthrough sites can effectively disrupt epicardial connections to the right pulmonary vein antrum, significantly enhancing the rate of atrial fibrillation-free survival.For the complete interruption of these epicardial pathways, ablation is necessary in a specific region, indicated by the area activated within a certain time frame following the onset of the epicardial activation in the right pulmonary vein antrum.TweetAblation targeting the breakthrough point of epicardial connections to the right pulmonary vein antrum is effective for pulmonary vein isolation.Graphic abstract