Impact of electrical connections between ipsilateral pulmonary veins on the second‐generation cryoballoon ablation procedure

Background Electrical connections between ipsilateral pulmonary veins (PVs) have been reported histologically and electrophysiologically. This study investigated the impact of electrical connections between ipsilateral PVs on PV isolation using second‐generation cryoballoons (CB2‐PVI). Methods Five hundred eleven atrial fibrillation patients, without any PV anomalies, underwent CB2‐PVI using one 28‐mm balloon and a single 3‐minute freeze strategy without any bonus applications. Results Overall, 1966 of 2044 (96.2%) PVs were isolated exclusively by using 28‐mm cryoballoons. Among them, 13 left superior PV (LSPVs) and two right superior PV were not persistently isolated by the first application despite a complete vein occlusion, but were isolated by subsequent applications targeting other ipsilateral PVs. Among the 13 LSPVs, six were transiently isolated by 87 (62‐146) second time‐to‐isolation LSPV applications, but were immediately reconnected after the application. The nadir balloon temperature during the LSPV application was similar between the 13 LSPVs not isolated by the LSPV application but were not so by subsequent left inferior PV (LIPV) applications and the 488 LSPVs persistently isolated by LSPV applications (−49.4℃ ± 4.3℃ vs −50.8℃ ± 5.1℃; P = 0.328). In 59 patients in whom the initial LSPV application failed despite a complete occlusion, LIPVs were targeted for the second applications in 31 patients, and both the LSPV and LIPV were simultaneously isolated in 13 of 31 (41.9%). Conclusions Electrical connections between ipsilateral PVs could have an impact on the CB2‐PVI procedure. When the vein isolation failed despite a complete occlusion, especially for left ipsilateral PVs, it was reasonable to target the other ipsilateral PV instead of repeatedly targeting the same vein.