Arrhythmogenic right ventricular dysplasia.

BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD) is a genetic cardiomyopathy characterized by ventricular arrhythmias and structural abnormalities of the right ventricle (RV). The discovery of desmosomal mutations associated with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) has led researchers to hypothesize equal right (RV) and left (LV) ventricular affliction in the disease process. The purpose of this paper is to provide an overview of ARVD and also to present the results of a new study of the morphological variants of ARVD METHODS AND RESULTS: Thirty-eight (age: 30+/-17 years; 18 male) family members of twelve desmosomal mutation-carrying ARVD probands underwent genotyping and cardiac magnetic resonance imaging (CMR). The CMR investigators were blinded to clinical and genetic data. Twenty-five individuals had mutations in PKP2, DSP, and/or DSG2 genes. RV abnormalities were associated with the presence of mutation(s) and with disease severity determined by criteria (minor=1; major=2) points for ARVD diagnosis. The only LV abnormality detected, the presence of intramyocardial fat, was present in four individuals. Each of these individuals was a mutation-carrier, while one had no previously described ARVD-related abnormality. On detailed CMR, a focal "crinkling' of the RV outflow tract and subtricuspid regions ("accordion sign") was observed in 60% of the mutation-carriers and none of the non-carriers (P<0.001). The sign was present in 0%, 37%, 71%, and 75% of individuals who met 1, 2, 3, and 4+ criteria points respectively (P<0.01).

CONCLUSION: Despite a possible LV involvement in ARVD/C, the overall LV structure and function are well preserved. Independent LV involvement is of rare occurrence. The "accordion sign" is a promising tool for early diagnosis of ARVD. Its diagnostic utility should be confirmed in larger cohorts.