Abstract 1768: Magnetic Resonance Imaging Reveals Novel Phenotypic Expression of Desmosomal Mutation in First-Degree Relatives of Patients with Arrhythmogenic Right Ventricular Dysplasia (ARVD). Prevalence and Clinical Significance in Patients Evaluated For ARVD.

Abstract

Background: In this report we present the prevalence and significance of a novel MRI abnormality that we identified in desmosomal mutation positive asymptomatic relatives of arrhythmogenic right ventricular dysplasia (ARVD) patients. Methods: MRI of 38 first-degree relatives was analyzed for abnormalities blinded to the mutation status. Focal crinkling of the right ventricle (accordion sign) was observed in 15/25 mutation positive vs. 0/13 mutation negative patients. The presence of this finding was sought in 207 patients evaluated for ARVD blinded to clinical history and was correlated with electrophysiologic findings. Results: Mean age of the population was 32±16, 61% had a family history of ARVD. Based on non-invasive testing the 207 patients were classified into 4 groups 1) 106 normal, 2) 57 Idiopathic ventricular tachycardia (VT), 3) 33 probable ARVD, 4) 11 definite ARVD. A family history of ARVD was present in 74%, 0%, 67% and 36% respectively. 43 patients had the “accordion sign” and the prevalence in the four groups was 10%, 5%, 70% and 100% respectively. The abnormality was seen in the sub-tricuspid region in 62%, outflow tract in 30% in both regions in 8%. After excluding group 4, 48% of patients with the accordion sign had T wave inversion’s beyond V1 compared with 7% of those without the sign (p<0.001). During electrophysiologic testing, reentrant VT could be induced in 44% (7/16) of patients with accordion sign compared to 2% (1/48) without the sign (p<0.01). Conclusion: Focal crinkling of the RV termed “Accordion sign” may represent an early manifestation of ARVD that correlates with mutation positive status and predicts inducibility of ventricular arrhythmias.