Background: Catheter ablation for idiopathic ventricular arrhythmias is well established for many origins of VA and recommended by international guidelines, especially for right ventricular outflow tract VA. However, catheter ablation for VA arising close to the great cardiac vein (GCV) can often be challenging, and data on this topic are scarce.

Methods: Analysis was performed in 25 consecutive patients (age 55±18 years, 16 male) who underwent invasive electrophysiologic study for catheter ablation of focal VA (2 for sustained ventricular tachycardia (VT), 23 patients for premature ventricular contractions (PVC) or non-sustained VT) originating from respectively close to the GCV from March 2009 to October 2022. In 11 patients there was no evidence of structural heart disease and a PVC induced cardiomyopathy was suspected in 8 patients. Six patients had a history of structural heart disease (n=3 dilated cardiomyopathy, n=2 coronary artery disease, n=1 myocarditis-related cardiomyopathy, n=1 anthracycline-induced cardiomyopathy). Nine patients underwent re-ablation after failed ablation at a different centre, five patients underwent re-ablation after VA recurrence during this time period. In all patients, a coronary angiography was performed in the course of the intervention. 

Results: Ablation was performed in GCV-sites in all 25 patients in 28/30 (93%) procedures after thorough endocardial mapping and/or failed ablation. Effective energy with an irrigated tip catheter was applicated at the site of earliest VA origin in the great cardiac vein in 24/28 (86%) and abolished VA in 16/24 (67%) ablation procedures, corresponding to achieving a primary success in 13/25 (52%) patients. In two patients, acute success of ablation could not be determined with certainty due to very few PVC during the intervention. Major adverse events occurred in three patients: In one patient, RF application caused a myocardial oedema resulting in a transient lumen reduction of the left coronary artery, another patient developed a pseudoaneurysm of the superficial femoral artery not requiring surgical intervention. One patient experienced mild pericarditis without myocardial involvement. In 2/25 patients (8%) epicardial ablation could initially not be performed due to only very few PVC (n=1) or limited vascular access to the coronary sinus (n=1). In 4/25 patients (16%), high impedances (n=2) or close proximity (<5mm) to the coronary arteries (n=2) prohibited effective energy application.

Conclusion: The present study reports acute ablation results in one of the largest series of epicardial ablations of VA originating near the GCV. In a significant proportion of patients, catheter ablation was successful while major adverse events e.g., lesions of the coronary arteries could be avoided. Further comparative studies on different techniques such as bipolar ablation are needed to identify the optimal interventional approach for these challenging origin of focal VA.