Regional differences in the effects of the ablation index and interlesion distance on acute electrical reconnections after pulmonary vein isolation

BACKGROUND: In pulmonary vein isolation, the regional differences in the ablation index (AI) and interlesion distance (ILD) remain unclear. This study aimed to evaluate the association between the AI, ILD, and other relevant indices with pulmonary vein reconnections (PVRs) during the surgical intervention with a focus on the heterogeneous regional variability through a retrospective analysis. METHODS: We divided the wide area circumferential ablation (WACA) region into 12 segments in 32 consecutive patients, which resulted in a 384 segment analysis to evaluate the association of the minimum AI (AI min) and maximum ILD (ILD max) with acute PVRs, which were defined as spontaneous PVRs or dormant conduction after adenosine triphosphate administration. RESULTS: Acute PVRs were observed in 48 (13%) segments and 40 (63%) WACA regions. The AI min was significantly lower and ILD max greater in segments with PVRs than in those without (372 vs 403 au and 6.5 vs 5.7 mm, respectively). PVRs were more frequent in the left posterior segments, adjacent to the esophagus, than in other segments (23% vs 10%, respectively). Notably, ILD max was significantly greater in the left posterior segments with acute PVRs with AI min < 297 (median; 6.5 vs 5.1 mm); a similar finding was not observed when with AI min ≥ 297. CONCLUSION: Smaller ILD may prevent acute PVRs when the AI min is low in the left posterior segments.