Clinical significance of structural remodeling concerning substrate characteristics and outcomes in arrhythmogenic right ventricular cardiomyopathy

BACKGROUND: The substrate and ablation outcome in arrhythmogenic right ventricular cardiomyopathy (ARVC) with or without right ventricular (RV) dysfunction is unclear. OBJECTIVE: We aimed to investigate ablation outcome and substrate in ARVC patients with or without RV dysfunction. METHODS: We retrospectively studied ARVC patients with (group 1) or without RV dysfunction (group 2) undergoing substrate mapping/ablation. Baseline characteristics and electrophysiological features were compared. The RV was divided into 7 prespecified segments. The scarred segment was defined as more than 50% of the area with bipolar scar. A multivariate regression analysis was performed to predict the risk of ventricular tachycardia (VT) recurrence. RESULTS: A total of 106 patients were enrolled (57 in group 1 and 49 in group 2). There were more men (73.7% vs 32.7%, P < .05) in group 1 than group 2. Group 1 patients demonstrated larger abnormal substrate in both the endocardium (13.4 ± 14.7 cm(2) vs 7.8 ± 5.4 cm(2), P = .014) and in the epicardium (40.3 ± 27.7 cm(2) vs 14.2 ± 12.6 cm(2), P = .002) and had more scar in the inferior portion/tricuspid valve (TV) than group 2 patients. Twenty-five patients had recurrences of VT/ventricular fibrillation. After multivariate analysis, the presence of a superior TV scar in the endocardium predicted the recurrence in patients with sustained VT. CONCLUSION: The presence of RV dysfunction was associated with a larger abnormal substrate in the endocardium and epicardium of the RV. A scar involving the inferior portion and TV is associated with RV dysfunction. Scarring in the superior TV of the endocardium can predict recurrence despite catheter ablation.