Vein of Marshall Ethanol Infusion as First Step for Mitral Isthmus Linear Ablation.

Objectives: In this study, the authors sought to investigate the added value of vein of Marshall ethanol infusion (VOMEt) as first step in facilitating radiofrequency (RF)-guided mitral isthmus (MI) block.
Background: Achieving MI block with the use of RF ablation is challenging.
Methods: Seventy patients planned for MI ablation were randomized 1:1 to VOMEt as a first step preceding RF (endocardial and epicardial, VOM _FIRST group) vs RF ablation as a first step preceding VOMEt (RF _FIRST group). The study end point was incidence of MI block after RF ablation and after the 2 steps.
Results: In VOM _FIRST , VOMEt was successful in 30/35 patients (86%) resulting in a low-voltage area of 12 ± 7.4 cm ² and MI block in 2/35 patients (6%). VOM _FIRST , compared with RF _FIRST , was associated with higher incidence of MI block after endocardial (46% vs 11%; P < 0.001) and epicardial ablation (94% vs 43%; P < 0.001), with fewer endocardial applications (4 vs 11 vs 4; P < 0.001) and similar epicardial applications (7 vs 8; P = 0.68). Incidence of MI block after the 2 steps was 94% vs 63% (P = 0.001) in VOM _FIRST vs RF _FIRST , respectively. Additional touch-up RF ablation in both groups resulted in final MI block in all but 1 patient (99%).
Conclusions: VOMEt as a first step in RF-guided MI line ablation significantly reduced the number of RF applications needed to achieve MI block, even if the sequence of the ablation steps did not affect the final incidence of block. (Evaluation of Vein of Marshall Ethanol Infusion During Left Atrial Linear Ablation in Patients With Persistent Atrial Fibrillation [MARSHALINE]; NCT04124328).
Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)