Vein of Marshall ethanol infusion related lesion durability. A randomized dual centre pilot study
Authors: Marchese P , Gennaro F , Mazzotta G , Garibaldi S , Nesti M , Mirizzi G , Panchetti L , Marcello P , Rossi L 
Published: May 2024

Abstract

Introduction
Vein of Marshall ethanol infusion (VOM-EI) creates a local ablation which includes epicardial bridges, AF triggers, vein innervation and facilitates mitral isthmus (MI) ablation. Recent trials demonstrated that in persistent AF patients the addition of VOM-EI to RF catheter ablation (CA) increased success rate vs CA alone. Moreover, a novel CA strategy (VOM-EI, PVI, and specific linear lesions set) is associated with a high rate of freedom from AF. Nevertheless, in these studies VOM-EI and RFCA were performed as different step of the same procedure. We hypothesize that performing electro-anatomical mapping (EAM) right after the VOM-EI would lead to an overestimation of ethanol-induced scar because of a certain amount of reversible oedema. This could affect the durability of the lesion set and possibly the success rate.

Aim
We postulated that VOM-EI performed at least 1 month earlier than RFCA would show a significantly smaller EAM low voltage area as compared to the standard strategy.

Methods
Patients with recurrent persistent AF with no history of previous ablation were enrolled in this randomized, dual centre, pilot study. All included patients were randomized 1:1 to
group 1 (experimental): VOM-EI and after at least one month later high-definition (HD)-EAM and RFCA (PVI, MI, LA dome, cavo-tricuspid isthmus).
group 2 (control): to a standard procedure (VOM-EI then 5 minute later HD-EAM and RFCA).
Primary endpoint was ethanol induced HD-EAM scar area. According to the endpoint patients with unsuccessful VOM-EI were excluded. Moreover patiets with or no branches morphology, VOM dissection, and mechanical leakage were also excluded because these are demonstrated to be related to a smaller VOM-EI related lesion. Clinical and procedure related data were also collected.

Results
Forty consecutive patients met the inclusion criteria. The two groups did not differ for baseline characteristics (see table 1). Mean ethanol-induced HD-EAM scar area was significantly smaller in 20 patients where VOM-EI was performed at least 1 month earlier as compared to the standard procedure group (2,5±2,4 vs 11,2±9,5 cm2, p=0,018). The set of linear lesions was successful achieved in all patients. Notably the two group did not differ for any procedural technical aspect of mitral isthmus block (table 1). Neither VOM-EI nor AF ablation procedure related complications were recorded.

Conclusion
This is the fist randomized pilot study to demonstrate that a consistent amount of ethanol-induced related lesion could be reversible at least in its endocardial aspect of the left atrium. This would possibly affect the long-term stability of the lesion set. Notably, we still had a high rate of block at first mitral line attempt which could possibly be related to a persistent effect of VEOM-EI on the epicardial aspect of the left atrium. Larger population, randomized trial is needed to confirm this preliminary result and if it would affect the procedure success.Table 1Picture 1