PURPOSE--To determine the value of the high-resolution ECG for the differential diagnosis of arrhythmogenic right ventricular disease. METHODS--A group of 33 patients were studied, 16 males, mean age 34 +/- 16 years. All patients presented non-sustained or sustained or repetitive monomorphic ventricular tachycardias, with left bundle branch block morphology. The anatomic and functional evaluation of the right ventricle was made by a previous echocardiogram. No patient presented left ventricular or septal pathology. High-resolution ECG were obtained from a Corazonix-Predictor II program. In the filtered QRS was analyzed root mean square of the last 40ms QRS, the final lasting of the low amplitude signals < 40 microV and filtered QRS duration. Ten patients underwent to electrophysiological study with right ventricular mapping. RESULTS--The ventricular tachycardias was non-sustained in 18 patients, sustained in 8 and repetitive monomorphic in 7 patients. The echocardiogram was normal in 23 patients, and all these also presented normal high resolution ECG. Among the 10 patients with altered echocardiogram, 9 presented abnormal high-resolution ECG (sensibility 90 per cent ; specificity 100 per cent ; positive predictive value 100 per cent ; negative predictive value 96 per cent ; efficacy of the method to define the presence of manifested right ventricular pathology was 96 per cent ). Among the 10 patients with altered echocardiogram, 8 underwent to electrophysiological study. In all was detected an abnormal ventricular mapping and abnormal high-resolution ECG. CONCLUSION--The high-resolution ECG is an useful method to define a right ventricular manifested pathology in presence of arrhythmogenic disease of this cavity