Efficacy and safety of ethanol infusion into the vein of Marshall for mitral isthmus ablation

Introduction: Chemical ablation by retrograde infusion of ethanol into the vein of Marshall (VOM-EI) can facilitate achievement of mitral isthmus block. This study sought to describe efficacy and safety of this technique. Methods and Results: Twenty-two consecutive patients (14 male, median age 71 years) with attempted VOM-EI for mitral isthmus ablation were included in the study. VOM-EI was successfully performed with a median of 4 ml of 96% ethanol in 19 patients (86%) and mitral isthmus was successfully blocked in all (100%). Touch up endocardial and/or epicardial ablation after VOM-EI was necessary in 12 patients (63%). Perimitral flutter was present in 12 patients (63%) during VOM-EI and terminated or slowed by VOM-EI in four and three patients, respectively. Low-voltage area of the mitral isthmus region increased from 3.1 cm2 (IQR 0-7.9) before to 13.2 cm2 (IQR 8.2-15.0) after VOM-EI and correlated significantly with the volume of ethanol injected (P = 0.03). Median high-sensitive cardiac troponin-T increased significantly from 330 ng/L (IQR 221-516) the evening of the procedure to 598 ng/L (IQR 382-769; P=0.02) the following morning. A small pericardial effusion occurred in three patients (16%), mild pericarditis in one (5%) and uneventful VOM dissection in two (11%). After a median follow-up of 3.5 months (IQR 3.0-11.0), 10 of 18 patients (56%) with VOM-EI and available follow-up had arrhythmia recurrence. Repeat ablation was performed in five patients (50%) and peri-mitral flutter diagnosed in three (60%). Conclusion: VOM-EI is feasible, safe and effective to achieve acute mitral isthmus block