A case of arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is a clinical entity characterized by predominantly right-sided cardiomyopathy associated with ventricular tachycardia (VT). We reported a case of ARVD, in which the diagnostic usefulness of radionuclide cardiac blood pool scan, myocardial imaging and X-ray CT was suggested. A 27-year-old man was referred in September, 1982 for evaluation and treatment of recurrent sustained VT. Physical examination was unremarkable except for the wide splitting of the second heart sound and the presence of the fourth heart sound. Chest X-ray films showed mild cardiomegaly (CTR 0.54). An ECG during sinus rhythm showed low voltage, left axis deviation, inverted T waves in leads V1 to V5 and a slight notching on the ST segment (postexcitation potential). The VT had a rate of 180/min and the QRS complexes of the VT showed a left bundle branch block configuration with left axis deviation. Technetium-99 m gated cardiac blood pool scan revealed a dilated hypokinetic right ventricle (RV) with a ejection fraction of 0.09. Thallium-201 myocardial imaging showed diminished tracer uptake in the RV wall, which suggested pathology in the RV myocardium. On X-ray CT, the CT number of the RV free wall was low(-60 Hounsfield units), suggesting fatty infiltration in the free wall. The results of our study suggested the value of the combined use of technetium-99 m gated cardiac pool scan, thallium-201 myocardial imaging and X-ray CT in the noninvasive diagnosis of patients with ARVD. (J.P.N.)