The infusion of ethanol via the vein of Marshall (VOM), coupled with catheter ablation, leads to improved outcomes for patients with persistent atrial fibrillation (AF).
Presented by Dr Miguel Valderrabano (Baylor College of Medicine, USA), the VENUS trial addressed the challenge of treating persistent AF, which is limited by the imperfect success of catheter ablation procedures, and the consequent need for repeat procedures . The investigators hypothesised that by ablating AF triggers in the VOM through retrograde ethanol infusion, coupled with a catheter ablation approach, the restoration of normal rhythm could be achieved in more patients with persistent AF.
Participants (n=343) with symptomatic persistent AF and refractory to at least 1 anti-arrhythmic agent were randomised to receive either catheter ablation alone (n=158) or catheter ablation combined with VOM ethanol (n=185). The investigators anticipated that approximately 15% of the patients randomised to the VOM group would have a VOM difficult to cannulate; those patients would continue in the study receiving only catheter ablation.
Outcomes were measured at 1, 3, 6, 9, and 12 months post-procedure, with continuous month-long monitoring taking place at the 6- and 12-month time points. Prior to catheter ablation, patients in the VOM group received a coronary sinus venogram to identify the VOM and angioplasty balloon cannulation with 4 retrograde injections of 1 cc of ethanol (from distal to proximal). Left atrial voltage maps were performed before and after the ethanol injection to assess the scar induced by the alcohol administration. Catheter ablation for both groups included pulmonary vein isolation. The extent of the total tissue ablated was determined by a final left atrial voltage map. The primary endpoint at 3 months was resolution of either AF or atrial tachycardia (AT) for more than ≥30 seconds, without anti-arrhythmic medication.
A total of 142 participants were included in the per-treatment analysis; the VOM procedure was unsuccessful in 30 patients, 3 patients died, and 10 participants had missing data. Notably, more patients in the VOM group had hypertension (77% vs 66%) and the atrial diameter was larger in the catheter ablation-only group (44.8 mm vs 47 mm). These distinctions should be considered in the results interpretation.
Resolution of AF or AT for more than 30 seconds after 3 months was achieved in 38% of the patients randomised to the catheter ablation group, and 51.6% among those in the VOM plus catheter ablation group (P=0.015, see Table). AF/AT recurrence was seen in 51.9% of the catheter ablation group, compared with 40% of those undergoing VOM infusion plus catheter ablation.
Table: Ablation success: Resolution of AF or AT ≥30 seconds after 3 months
AF, atrial fibrillation; AT, atrial tachycardia; CI, confidence interval; VOM, vein of Marshall.
Dr Valderrabano concluded: “In persistent AF, VOM ethanol added to catheter ablation reduces the recurrence of AF and AT, reduces the AF, and may reduce the need for repeat procedures.”
- Valderrabano M et al. Abstract 409-12, ACC/WCC 28-30 March 2020.
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