Efficacy and safety of vein of marshall ethanol infusion as an adjunct to catheter ablation in persistent atrial fibrillation: a systematic review and meta-Analysis

Background Atrial tachyarrhythmia (ATa) recurrence after catheter ablation for atrial fibrillation (AF) remains clinically significant. Ethanol infusion into the vein of Marshall (EIVoM) may enhance mitral isthmus bidirectional block (MIBB) and reduce arrhythmia recurrence but its adjunctive role requires robust synthesis. Methods We systematically searched PubMed, EMBASE, Scopus and Cochrane Library from inception up to May 2025 for randomized controlled trials (RCTs) comparing EIVoM plus catheter ablation versus ablation alone in AF patients. Primary outcomes were ATa recurrence (>30 seconds after 3-month blanking), MIBB, repeat ablation, subacute pericardial effusion (not requiring drainage) and pseudoaneurysm. Pooled risk ratios (RR) with 95% confidence intervals (CI) were calculated using Mantel-Haenszel random-effects models. Heterogeneity was assessed via I² and ꭓ2 statistics. Risk of bias was assessed using Risk of Bias (RoB) 2.0 tool, analysis was performed using Review Manager version 5.4. Results This meta-analysis of 3 RCTs involving 927 patients (476 in adjunctive EIVoM + ablation group, 451 in ablation alone group) with atrial fibrillation with mean left atrial diameter 46.7 ± 1.8 mm. The mean age of the patients was 64. 3± 2.1 years. Adjunctive EIVoM significantly reduced atrial tachyarrhythmia recurrence (RR 0.79; 95% CI 0.68–0.91; P = 0.001), increased mitral isthmus bidirectional block rates (RR 1.32; 95% CI 1.11–1.57; P = 0.001) and lowered repeat ablation requirements (RR 0.65; 95% CI 0.44–0.96; P = 0.03) compared to ablation alone. However, EIVoM was associated with a higher risk of subacute pericardial effusion (RR 2.21, 95% CI 1.07–4.58; P = 0.03), while pseudoaneurysm incidence showed no significant intergroup difference (RR 0.45, 95% CI 0.06–3.48; P = 0.44). Conclusion Adjunctive vein of Marshall ethanol infusion enhances the effectiveness of catheter ablation in persistent atrial fibrillation by significantly reducing arrhythmia recurrence and repeat procedures, while improving mitral isthmus block rates. Despite a modest increase in subacute pericardial effusion, its overall benefits position EIVoM as a promising strategy to optimise ablation outcomes.