# The Role of Ethanol Ablation of the Vein of Marshall in the Era of Pulsed Field Ablation

## TL;DR

This paper reviews the effectiveness of ethanol ablation of the vein of Marshall in treating atrial fibrillation, especially in the context of new pulsed field ablation techniques.

## Contribution

The paper provides a comprehensive review of clinical evidence supporting ethanol instillation into the vein of Marshall as an adjunctive ablation strategy.

## Key findings

- Ethanol instillation into the vein of Marshall improves outcomes in patients with persistent atrial fibrillation.
- Three randomized trials have consistently supported the benefit of ethanol instillation into the vein of Marshall.
- Pulsed field ablation is changing the ablation landscape, raising questions about the future role of ethanol ablation.

## Abstract

Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and is associated with significant morbidity, mortality, and health care expenditure. Catheter ablation is the most effective treatment strategy to decrease AF burden, a measure strongly correlated with significant clinical outcomes. For the last two decades, pulmonary vein isolation (PVI) has remained the cornerstone of the ablation procedure, with single procedure success rates as high as 90% in patients with paroxysmal AF. These favorable outcomes have not translated to patients with persistent AF, who harbor more atrial remodeling and who may require ablation beyond PVI. While most PVI-adjunctive ablation strategies have not survived the rigor of randomized control trials, in 2020, VENUS showed that adjunctive ethanol instillation into the vein of Marshall (EIVOM) improved clinical outcomes in patients with persistent AF. Since VENUS, three other randomized trials have consistently shown a benefit of adjunctive EIVOM, though utilization of this technique remains low due to a multitude of factors. In parallel to the mounting evidence supporting EIVOM, pulsed-field ablation (PFA) has revolutionized the landscape and has called into question the ongoing role of EIVOM. This review examines the electrophysiologic significance of the VOM and summarizes the clinical evidence supporting adjunctive EIVOM in the era of PFA.