B-PO01-063 LATER ONSET OF FIRST SUSTAINED RBBB-VT AS COMPARED TO FIRST LBBB-VT IN PATIENTS WITH ARRHYTHMOGENIC CARDIOMYOPATHY

Abstract

In patients with arrhythmogenic cardiomyopathy (ACM), sustained ventricular tachycardia (VT) with a right bundle branch block morphology (RBBB-VT) is rarely documented despite a frequent left ventricular (LV) involvement. The natural history of RBBB-VT in ACM as compared to its LBBB-VT counterpart is poorly known. To compare the age of onset of first documented sustained VT of either morphology in a large cohort of ACM patients. A European survey including 26 centers from 11 countries enabled the collection of information on 954 patients with ACM and >1 episode of spontaneous sustained monomorphic VT observed during patients' clinical course. ACM was defined according to the 2010 Task Force criteria, and VT morphology according to the QRS pattern in V1. Of the 954 study patients (78.9% males), 882 (92.5%) patients displayed LBBB-VT alone and 72 (7.5%) patients RBBB-VT [alone in 42 (4.4%) or in combination with LBBB-VT in 30 (3.1%)]. Age at first documented sustained VT ranged from 7 to 87 (mean 41.5+15.8) years. At the first VT of any morphology, patients who displayed RBBB-VT (n=60) were significantly older than those (n=894) who displayed LBBB-VT (46.5+14.4 vs. 41.1+15.8 years, respectively, P=0.01). The mean ages at first VT of any morphology were not significantly different between males and females (41.3+15.9 years vs. 42.1+15.2 years, respectively, P=0.49). In ACM, RBBB-VT occurs later than LBBB-VT. Whether LV arrhythmogenic remodeling occurs later in the course of the disease, or whether the thicker LV wall may be less vulnerable to fibro adipose transformation so that a longer evolution of the disease may be required for RBBB-VT to occur, is unknown.