Vein of Marshall chemical ablation decreases atrial fibrillation drivers detected by CARTOFINDER

Abstract Introduction This study sought to elucidate the impact of vein of Marshall (VOM) chemical ablation on atrial fibrillation (AF) drivers by investigating the changes in CARTOFINDER mappings before and after VOM chemical ablation in patients with persistent AF. Methods This study included 23 consecutive patients undergoing catheter ablation for long‐persistent AF (>18 months). VOM chemical ablation was performed following pulmonary vein isolation. CARTOFINDER and AF cycle length (AFCL) maps were created in the left atrium (LA) before and after VOM chemical ablation. The LA was divided into 8 segments, and the number of focal activation points with 6 or more repetitions was counted in each segment. Results The number of focal activation points was largest in the LA appendage (LAA). After VOM chemical ablation, the number of focal activation points in the LA decreased significantly (37 [interquartile range, IQR: 19–55] vs. 15 [IQR: 7–21], p < .001), and median AFCL was significantly prolonged (159 [147–168] vs. 164 [150–173] ms, p < .001). In the assessment of each segment, significant decreases in focal activation points were observed in the inferior, lateral, and anterior segments and LAA. Among the focal activation points disappearing after chemical ablation, the number in the non‐ethanol‐affected area was significantly larger than that in the affected area (13 [8–25] vs. 4 [1–10], p < .001). Conclusions VOM chemical ablation decreases AF drivers detected by CARTOFINDER. Mechanisms other than direct myocardial damage are considered to contribute the attenuation of AF drivers.