Background: Electron-beam computed tomography (CT) may be useful for detecting myocardial fat infiltration and diagnosing arrhythmogenic right ventricular dysplasia (ARVD). There are several characteristic electron-beam CT findings of ARVD. However, the incidence, their relation to electrophysiological abnormalities, and the usefulness of electron-beam CT for evaluating left ventricular involvement are unknown. This study aimed to clarify these issues.
Methods and results: Electron-beam CT was performed in 14 patients with ARVD (ARVD group), 16 age- and sex-matched patients with right ventricular enlargement and/or dysfunction without ARVD (RV enlargement group), and 13 control subjects (control 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 electrophysiologically abnormal areas detected in the mapping electrophysiology 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%, respectively, in the ARVD group, whereas these findings were not observed in the RV enlargement and control groups. (2) Three ARVD patients (21%) had adipose tissue involvement of the left ventricle. (3) The relationship 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-beam CT findings are frequently observed only in patients with ARVD. Electron-beam CT is useful for evaluating for left ventricular involvement and can estimate EPS-A.