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

Abstract

BackgroundThe substrate and ablation outcome in arrhythmogenic right ventricular cardiomyopathy (ARVC) with or without right ventricular (RV) dysfunction is unclear.ObjectiveWe aimed to investigate ablation outcome and substrate in ARVC patients with or without RV dysfunction.MethodsWe 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.ResultsA 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 cm2 vs 7.8 ± 5.4 cm2, P = .014) and in the epicardium (40.3 ± 27.7 cm2 vs 14.2 ± 12.6 cm2, 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.ConclusionThe 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.