Ablation of Ventricular Arrhythmias in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy: Arrhythmia-Free Survival after Endo-Epicardial Substrate Based Mapping and Ablation

Background —In patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), freedom from ventricular arrhythmias (VAs) after endocardial ablation is limited. We compared the long term freedom from recurrent VAs by using endocardial-alone ablation vs. endo-epicardial substrate based ablation. Methods and Results —49 patients with ARVD/C undergoing ablation of ventricular tachycardia (VT) were divided into 2 groups: endocardial-alone ablation (Group 1, n=23) and endo-epicardial ablation (Group 2, n=26). All patients had an implantable cardioverter defibrillator (ICD). Conventional and 3D mappings were utilized to determine the mechanism of induced VTs and to identify area of "scar" or "abnormal" myocardium. All critical sites responsible for VTs and points with "abnormal" potential were targeted for ablation from endocardium (Group 1) or from both endocardium and epicardium (Group 2). Procedural endpoint was noninducibility of sustained, monomorphic VT with isoproterenol. The presence of frequent premature ventricular contractions (PVCs) at the end of ablation was recorded. Patients were followed-up by ECGs, Holter and ICD interrogation. After a follow up of at least 3 years, freedom from VAs or ICD therapy was 52.2% (12/23) in Group 1 and 84.6% (22/26) in Group 2 (p=0.029) with 21.7% (5/23) and 69.2% (18/26) patients off AAD (p<0.001), respectively. Compared to patients with no PVC after ablation, patients with frequent PVCs after ablation were more likely to have VA recurrence/ICD therapy [3/33, (9%) vs. 12/16 (75%), Log rank p<0.001]. Conclusions —An endo-epicardial based ablation strategy achieves higher long-term freedom from recurrent VAs off anti-arrhythmic therapy in patients with ARVD/C when compared to endocardial-alone ablation. The presence of ≥10 PVCs per minute after ablation is associated with more VA recurrence.