Abstract
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.