Impact of Adjunctive Vein of Marshall Ethanol Infusion on Catheter Ablation Outcomes in Atrial Fibrillation: A Systematic Review and Meta‐Analysis

ABSTRACT Background Catheter ablation (CA) for atrial fibrillation (AF) has limited efficacy. The vein of Marshall (VOM) is associated with autonomic innervation and has arrhythmogenic roles in AF, which can be ablated with ethanol infusion. However, the impact of VOM ethanol infusion (VOMEI) on the recurrence of atrial tachyarrhythmia (ATA) remains unclear. Methods We systematically searched PubMed, Embase, and Cochrane databases for randomized controlled trials (RCTs) and observational studies comparing CA with versus without VOMEI in patients with AF. Outcomes were ATA recurrence and mitral isthmus (MI) block rate. ATA recurrence was defined as AF, atrial flutter, or atrial tachycardia following the index procedure. Sensitivity analyses were performed after restricting to patients with persistent AF, undergoing a re‐do procedure, and RCTs. Results This meta‐analysis included 4 RCTs and 16 observational studies, comprising a total of 4732 patients, of whom 2105 (44%) underwent VOMEI. The mean follow‐up ranged from 12 to 46.8 months. Compared with CA alone, VOMEI was associated with a significantly lower ATA recurrence (OR: 0.51; 95% CI: 0.40–0.65; p < 0.01) and significantly higher rates of MI block rate (OR: 4.41; 95% CI: 2.47–7.88; p < 0.01). Subgroup analysis also revealed significantly lower ATA recurrence with adjunctive VOMEI in patients with persistent AF at baseline (OR: 0.47; 95% CI: 0.35–0.64; p < 0.01), those undergoing a re‐do procedure (OR: 0.44; 95% CI: 0.33–0.61; p < 0.01), and after restricting to RCTs (OR: 0.58; 95% CI: 0.44–0.76; p < 0.01). Conclusion In patients with AF, adjunctive VOMEI combined with CA was associated with reduced ATA recurrence compared to CA alone, particularly in those with non‐paroxysmal AF at baseline or undergoing a repeat ablation. Additionally, VOMEI was linked to significantly higher rates of mitral isthmus block, which may have contributed to the observed outcomes.