BACKGROUND: The best approach for ablating ventricular tachycardia (VT) targeting right ventricular (RV) free wall aneurysms in arrhythmogenic right ventricular cardiomyopathy (ARVC) remains undefined. OBJECTIVE: We aimed to describe the technical approach, safety, and long-term efficacy of endocardial ablation of VT originating from RV free wall aneurysms in ARVC patients. METHODS: We identified ARVC patients with VT mapped to intracardiac echocardiography (ICE)-defined RV free wall aneurysms who underwent endocardial ablation targeting the aneurysmal area. RV free wall aneurysm on ICE was defined as an akinetic or dyskinetic area with diastolic bulging. The primary ablation end point was VT control, defined as freedom from any or multiple (>
1) VT recurrences. RESULTS: From 2012 to 2023, 14 ARVC patients underwent endocardial VT ablation within ICE-defined RV free wall aneurysms. The median age at first arrhythmia event was 55.5 years (interquartile range [IQR], 32.3-59.8 years). Pathogenic genetic variants were identified in 82% of the patients. Ablation inside the RV aneurysms during ICE monitoring used prolonged radiofrequency applications (median, 111 seconds
IQR, 81-180 seconds), with power titrated up to 29 W (IQR, 29-33 W) to achieve 10%-15% impedance drops. No steam pops occurred. VT noninducibility was achieved in 86% with no complications. During median follow-up of 4.3 years (IQR, 3.1-6.0 years), the primary end point was achieved in 13 patients (93%): 10 VT free and 3 with a single episode of VT. CONCLUSION: Endocardial ablation targeting VT from ICE-defined RV free wall aneurysms in ARVC patients using prolonged radiofrequency applications is safe and effective, precluding the need for adjunctive epicardial ablation. Patients with aneurysm-dependent VT were typically older and carried pathogenic genetic variants.