1222Characteristics of an arrhythmogenic substrate and results of catheter ablation of ventricular arrhythmias in patients with desmoplakin mutation associated arrhythmogenic cardiomyopathy

Abstract

Background: Mutations of desmoplakin gene are associated with arrhythmogenic cardiomyopathy (ACM) with dominant left ventricular (LV) involvement and recurrent ventricular tachycardias (VTs). However, limited data exist regarding outcome of catheter ablation in these patients. Purpose: We aimed to analyze characteristics of an arrhythmogenic substrate and outcome of catheter ablation in this population. Methods: We report 9 patients (mean age 48±15 years, 2 females) with ACM and genetically verified pathogenic mutation of desmoplakin gene. All but one patient had systolic dysfunction of both ventricles with mean LV ejection fraction of 35±9%. All patients had implantable cardioverter-defibrillator and underwent radiofrequency catheter ablation for recurrent VTs. Results: A mean of 2.3±1.1 monomorphic VTs per patient were inducible during an electrophysiological study. Epicardial access for mapping and ablation was needed in 6/9 (67%) patients. In all of them arrhythmias originated from LV inferolateral/lateral aspect. Electroanatomical epicardial mapping revealed in this location areas of abnormal/late potentials that were not detectable from endocardial surface. Two patients (22%) had substrate located at right ventricular free wall, which was targeted from endocardium and resulted in VT noninducibility. One patient with end-stage heart failure had VTs originating from midventricular anteroseptal LV scar. During a median follow-up of 5 months, 6/9 (67%) patients were free of VT recurrences and substantial decrease in arrhythmia burden was observed in 2 other patients (one had epicardial ablation, one only endocardial). One patient died remotely because of end-stage heart failure and one underwent successful heart transplant. Conclusions: Patients with desmoplakin gene mutation have distinct arrhythmogenic substrate that is predominantly located at epicardial aspect of the lateral/inferolateral LV wall. In the setting of refractory VTs, catheter ablation is an important treatment option that results to acceptable rates of freedom from arrhythmia recurrences and clinically highly significant decrease of arrhythmia burden.