Role of magnetic resonance imaging in arrhythmogenic right ventricular dysplasia: insights from the North American arrhythmogenic right ventricular dysplasia (ARVD/C) study.

Background: Prior reports describing magnetic resonance (MR) imaging abnormalities in arrhythmogenic right ventricular dysplasia (ARVD/C) were limited by nonuniform inclusion criteria. The aim of our study was to define the prevalence, sensitivity, and specificity of quantitative MR imaging findings in the probands of multidisciplinary study of right ventricular dysplasia.

Methods: Individuals with ventricular arrhythmias of left bundle-branch block morphology meeting the Task Force criteria for ARVD/C underwent MR imaging. The MR images were compared with 10 patients with idiopathic ventricular tachycardia (VT) and 25 controls. Of the 42 study probands, 40 met the Task Force criteria exclusive of MR imaging findings. All MR images were interpreted in a blinded fashion.

Results: Right ventricle fat infiltration was reported in 24 (60%) probands and none of the patients with idiopathic VT or controls. Six patients (15%) had fat infiltration of the left ventricle. Right ventricle regional dysfunction was observed in 32 probands (80%) and none of the patients with idiopathic VT or controls. Qualitative RV function was abnormal in 26 probands (60%); however, quantitative RV ejection fraction was abnormal in 85% (24/28) of the probands. An RV ejection fraction <50% had a sensitivity of 73% and a specificity of 95% in diagnosis of ARVD/C.

Conclusions: Fat infiltration is seldom the only MR imaging abnormality and is less sensitive for ARVD/C diagnosis compared with RV regional dysfunction. Qualitative estimates of RV function may underestimate the prevalence of RV dysfunction in ARVD/C. Quantitative evaluation of RV by MR imaging may have a high sensitivity and specificity for ARVD/C diagnosis.