USEFULNESS OF ELECTRON-BEAM COMPUTED-TOMOGRAPHY IN ARRHYTHMOGENIC RIGHT-VENTRICULAR DYSPLASIA - RELATIONSHIP TO ELECTROPHYSIOLOGICAL ABNORMALITIES AND LEFT-VENTRICULAR INVOLVEMENT

Background Electron-beam computed tomography (CT) may be useful for de tecting myocardial fat infiltration and diagnosing arrhythmogenic righ t ventricular dysplasia (ARVD). There are several characteristic elect ron-beam CT findings of ARVD. However, the incidence, their relation t o electrophysiological abnormalities, and the usefulness of electron-b eam CT for evaluating left ventricular involvement are unknown. This s tudy aimed to clarify these issues. Methods and Results Electron-beam CT was performed in 14 patients with ARVD (ARVD group), 16 age- and se x-matched patients with right ventricular enlargement and/or dysfuncti on without ARVD (RV enlargement group), and 13 control subjects (contr ol group). The incidences of abnormal electron-beam CT findings in the three groups were examined. Furthermore, we examined the endocardial fat-infiltrated areas detected by electron-beam CT (CT-A) and electrop hysiologically abnormal areas detected in the mapping electrophysiolog y study (EPS-A) and compared the relationship between them in the ARVD group. (1) The frequencies of abundant epicardial adipose tissue, low -attenuation trabeculations, scalloping of the right ventricular free wall, and intramyocardial fat deposits were 86%, 71%, 79%, and 50%, re spectively, in the ARVD group, whereas these findings were not observe d in the RV enlargement and control groups. (2) Three ARVD patients (2 1%) had adipose tissue involvement of the left ventricle. (3) The rela tionship between CT-A and EPS-A was as follows: CT-A>EPS-A, 71%; CT-A= EPS-A, 14%; and EPS-A only, 14%. Conclusions Characteristic electron-b eam CT findings are frequently observed only in patients with ARVD. El ectron-beam CT is useful for evaluating for left ventricular involveme nt and can estimate EPS-A.