OBJECTIVE: To evaluate the safety, efficacy, and long-term effects of catheter ablation with vein of Marshall ethanol infusion for bidirectional mitral isthmus block in patients with persistent atrial fibrillation. METHODS: Two hundred and forty patients from five centers with persistent atrial fibrillation (AF) who underwent radiofrequency ablation from October 2018 to December 2023 were retrospectively analyzed, including 120 patients who underwent traditional pulmonary vein isolation (PVI Only group) and 120 patients who underwent PVI and Marshall vein ablation (Marshall Plus group). The operation time, X-ray exposure, incidence of AF/atrial tachycardia (AT) and complications were compared between the two groups. RESULTS: Among the 240 patients (mean age: 57.2 ± 7.2 years, males: 195/240, 81.25 %), vein of Marshall ethanol infusion was successfully performed in 113 of 120 patients. At 12 and 36 months, the proportion of patients free from AF/ AT after a single procedure was 76.3 % (90/118) in the PVI plus vein of Marshall ethanol infusion group and 67.5 % (79/117) in the PVI only group (P <
0.01). Perimitral block was successfully achieved in 90.8 % (109/120) patients in the Marshall Plus group. Freedom from AF/AT at the 3-year follow-up (68.6 % vs. 59.8 %, P <
0.01) and incidence of adverse events were similar between the two groups. CONCLUSION: PVI combined with Marshall venous infusion ablation can safely and effectively increase the long-term success rate of AF ablation. Duration of AF, left atrial volume(>
42 mm,)and bidirectional mitral isthmus block were associated with recurrence of AF/AT.