Vein of Marshall Ethanol Infusion: Feasibility, Pitfalls, and Complications in over 700 Patients

Background - Vein of Marshall (VOM) ethanol infusion is a relatively new therapeutic option for atrial tachyarrhythmias. We aimed to evaluate the feasibility, pitfalls, and complications associated with this procedure in a large cohort of patients. Methods - Successful ethanol infusion, VOM-related lesion extent, and serious complications were evaluated in 713 consecutive patients treated with VOM ethanol infusion. Results - While feasible in 88.9% of cases, VOM ethanol infusion failure mainly resulted from non-identification (6.2%), non-cannulation (1.5%), or ethanol infusion in the wrong vein (1.7%). The Vieussens valve was a helpful landmark and was visible in 63.2% of cases. Multivariable analysis identified previous coronary sinus ablation as the only predictor for non-identification. The mean area of VOM-related endocardial scarring was 10.2±5.3 cm 2 . VOM dissection (10.7%), iodine leakage (3.0%), and VOM morphology without visible branches (3.0%) were associated with smaller VOM-related scarring (5.0±3.9 cm 2 , 6.6±3.5 cm 2 and 4.7±2.3 cm 2 , with a p <0.0001, p <0.044, and p <0.0001, respectively). Ethanol infusion in a wrong vein was associated with less mitral line block (72.7% vs. 95.8%, p=0.012). A total of 14 serious complications (2.0%) occurred: 7 tamponades, of which were 6 delayed and treated with pericardiocentesis (2 of these patients had per-procedural VOM perforation), 4 strokes, 1 anaphylactic shock, 1 atrioventricular block, and 1 left appendage isolation. Only 4 of these complications occurred during the procedure. Conclusions - Although limited by previous coronary sinus ablation, VOM ethanol infusion is a highly feasible treatment for atrial tachyarrhythmia, with a low rate of serious complications.