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

Abstract

Introduction Chemical ablation by retrograde infusion of ethanol into the vein of Marshall (VOM‐EI) can facilitate the achievement of mitral isthmus block. This study sought to describe the efficacy and safety of this technique. Methods and Results Twenty‐two consecutive patients (14 males, 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 the mitral isthmus was successfully blocked in all (100%). Touch up endocardial and/or epicardial ablation after VOM‐EI was necessary for 12 patients (63%). Perimitral flutter was present in 12 patients (63%) during VOM‐EI and terminated or slowed by VOM‐EI in 4 and 3 patients, respectively. The low‐voltage area of the mitral isthmus region increased from 3.1 cm2 (interquartile range [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 = .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 = .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.

Impact of technical aspects of vein of Marshall ethanol infusion on mitral isthmus block for persistent atrial fibrillation ablation

“…It was well-known that the ethanol dose was found to correlated with LVA size (10), which was consistent with the finding in our study. However, the correlation of ethanol dose with the success of MIth block had not been reported to the best of our knowledge.…”

“…The PentaRay catheter roved slowly in the LA to reconstruct the LA geometry as well as acquire 200-3,000 points evenly distributed at every aspect of the LA. Low voltage area (LVA) was defined as local bipolar peak-topeak potential ≤0.3 mV during sustaining AF or ≤0.5 mV in NSR (Figures 1C,D) (10,16), and was displayed as a red zone on LA geometry. The LVA contour was drawn manually and the LVA size was calculated by the built-in software tool of CARTO 3 system (Biosense Webster, USA).…”

“…Dehydrated ethanol infusion into the VOM (EIVOM) is a novel approach initially proposed to facilitate left PV isolation ( 8 ). Subsequently it was found that additional EIVOM was associated with markedly shorter MIth ablation time, higher rate of MIth block ( 9 , 10 ) and lower rate of recurrent atrial tachyarrhythmias (ATa) ( 11 – 13 ), compared with radiofrequency catheter ablation (RFCA) alone. Despite its consistently positive role in PeAF ablation in numerous studies, EIVOM could only be achieved in about 80.3–92% ( 11 – 13 ) of patients due to anatomical limitations; Furthermore, there were remarkable disparities with respect to ethanol dose, balloon position and timing of EIVOM relative to RFCA.…”

“…Later on, a total of 9–12 ml ethanol was injected with 3 ml over 1 min for each infusion ( 11 – 13 ). The over-the-wire (OTW) balloon was either positioned distally for the first infusion and gradually retracted to the proximal VOM for sequential infusions ( 9 , 13 ), or at the fixed site of the proximal VOM during all infusions in different studies ( 10 , 14 ). EIVOM was the first step of ablation in most studies ( 9 – 14 ), while it was performed following RFCA in a few studies ( 6 ).…”

Pulsed-field ablation for the treatment of left atrial reentry tachycardia

“…Different strategies have been adopted to overcome the limitations of RF energy. The most successful strategy may be ethanol injection into the vein of Marshal for mitral isthmus line ablation, or adjunctive epicardial ablation for roof lines (4)(5)(6)(7). However, these adjunctive approaches are time-consuming and limited to experienced centers.…”