Role of cardiovascular magnetic resonance imaging in arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is a progressive cardiomyopathy primarily affecting the right ventricle (RV) and is characterized by fatty/fibro-fatty replacement with myocyte loss, ventricular arrhythmias of left bundle branch block pattern (LBBB) and right heart failure. Increasing evidence suggests that ARVD is a disease of desmosomal dysfunction. ARVD can exist in both sporadic and familial forms with the familial form showing a predominantly autosomal dominant inheritance pattern with variable penetrance. The exact prevalence is unknown, but it is estimated to be 1:5000 in the United States. The clinical onset of ARVD is often delayed to adolescence or early adulthood. It is more commonly seen in males and people engaged in athletics and competitive sports.ARVD accounts for up to 5% of sudden deaths in young individuals less than 35 years of age in the United States, and 25% of exercise-related deaths in Veneto, Italy [1,2]. The death rate for patients with ARVD has been estimated at 2.5% per year [3]. The main differential diagnosis of ARVD consists of right ventricular outflow tract (RVOT) tachycardia, sarcoidosis, idiopathic dilated cardiomyopathy, isolated myocarditis, adipomatosis cordis, mitral valve prolapse, non-coronary precordial ST-segment elevation (Brugada syndrome) and the Uhl anomaly, which is characterized by a paper-thin RV due to almost complete absence of myocardial fibers [4].The diagnosis of ARVD is based upon a set of major and minor criteria proposed by the Task Force of cardiomyopathies in 1994 [5]. The diagnostic criteria (Table 1) are based upon a number of diverse genetic, electrocardiographic, pathophysiologic, histopathologic and imaging abnormalities. Patients must have either two major criteria, one major and two minor criteria, or four minor criteria to be labeled as affected with ARVD.Important morphological patterns of ARVD manifestation include myocyte loss with fibro-fatty replacement of the ventricular myoc