A case of arrhythmogenic right ventricular dysplasia with prominent late potential.

A case of arrhythmogenic right ventricular dysplasia with frequent episodes of ventricular tachycardia (VT) in a 57-year-old man is reported. His electrocardiogram showed a normal axis and inverted T waves in V1-V3 during sinus rhythm and a left bundle branch block pattern during VT. The VT could be terminated by either intravenous administration of lidocaine or procainamide or by cardioversion. Echocardiogram and right ventriculography showed reduced wall motion of the apex and infundibulum of the dilated right ventricle. No evidence of ischemic heart disease was found by left ventriculography, coronary arteriography and RI scintigraphy. A prominent late potential following the QRS complex was recorded by averaging and magnifying the surface electrocardiogram. The combination of oral mexiletine and disopyramide partially suppressed the VT attacks and relieved the subjective symptoms, however the late potential remained almost unchanged.