1 | INTRODUCTION
Endocardial radiofrequency catheter ablation of the mitral isthmus is commonly performed for peri-mitral reentrant tachycardia or as part of ablation strategy for persistent atrial fibrillation.1,2 Ablation of the mitral isthmus is challenging due to the anatomical complexity and the thickness of the tissue in this region, and because of epicardial cooling by the coronary sinus (CS) and circumflex artery.3 With both endocardial and epicardial ablation from inside the CS, acute complete bi-directional block of the mitral isthmus is achieved in only about 70% of patients.4,5
The ligament of Marshall is an epicardial vestigial fold that contains the vein of Marshall (VOM) and the Marshall bundle.6The VOM drains into the CS and runs posteriorly and superiorly along the epicardial surface of the left atrium, to join the anterior aspect of the left-sided pulmonary veins. Myofibers of the VOM can form an epicardial bridge over the mitral isthmus, preventing successful ablation from the endocardium and from within the CS.7
In 2009, Valderrabano et al. first described chemical ablation of the VOM by retrograde infusion of ethanol into the VOM (VOM-EI) and showed that VOM-EI can facilitate mitral isthmus ablation.8,9Subsequently, other groups adopted and refined the technique of VOM-EI for mitral isthmus ablation with high success rates.10Linear ablation of the mitral isthmus is an additional target of ablation of persistent atrial fibrillation, and VOM-EI may be used in these patients. The recent VENUS-trial, a prospective multicentre randomized study, showed improved arrhythmia-free outcome in patients with persistent atrial fibrillation treated with catheter ablation with supplement ethanol infusion into the vein of Marshall.11
The aim of the present study was to describe our single-centre experience of efficacy and safety of VOM-EI for mitral isthmus ablation.