Comprehensive Substrate Modification in Persistent AF: PVI Plus Posterior Wall Isolation With and Without Vein of Marshall Ethanol Infusion and Mitral Isthmus Ablation

ABSTRACT Background Pulmonary vein isolation (PVI) remains the primary ablation strategy for atrial fibrillation (AF). However, additional interventions are often required in patients with persistent AF. Ethanol infusion into the vein of Marshall (EIVOM) offers access to epicardial arrhythmic circuits, which has demonstrated incremental benefit in patients with persistent AF. Aim This study aimed to evaluate whether adding VOM ethanol infusion and mitral isthmus ablation to PVI with posterior wall debulking improves long‐term arrhythmia outcomes in patients with persistent AF. Methods A total of 123 patients with persistent AF undergoing catheter ablation between June 2021 and December 2023 were retrospectively analyzed. Patients were assigned to PVI + posterior wall debulking (PWD) ( n = 85) or PVI + PWD + VOM ethanol infusion + mitral isthmus ablation ( n = 38). Demographic, clinical, echocardiographic, and laboratory data were compared. Recurrence of atrial tachyarrhythmia was assessed using Kaplan–Meier survival analysis, and predictors of recurrence were evaluated with Cox proportional hazards models. Results During a median follow‐up of 12–15 months, long‐term arrhythmia recurrence occurred in 12.9% of patients treated with PVI + PWD and 7.9% of those receiving the additional VOM and mitral isthmus ablation extended approach ( p = 0.546). The unadjusted model showed a nonsignificant trend toward reduced recurrence with VOM ethanol infusion (hazard ratio HR 0.82, 95% confidence interval CI 0.45–1.22), which remained similar after multivariate adjustment (HR 0.80, 95% CI 0.52–1.18). Conclusions Although adjunctive VOM ethanol infusion and mitral isthmus ablation resulted in a lower observed recurrence rate, no statistically significant improvement in long‐term rhythm outcomes was observed.