A 35 year old female patient was referred for investigation and treatment of recurrent ventricular tachycardia. Cardiac examination and the echocardiogram were normal. Equilibrium radionuclide ventriculography demonstrated a reduction in right ventricular ejection fraction (rest and exercise) while left ventricular ejection fraction was normal. It is proposed that radionuclide ventriculography may be the noninvasive study of choice to screen patients for arrhythmogenic right ventricular dysplasia. The right ventricular response to exercise may provide additional evidence for right ventricular dysfunction based on relative changes compared to the left ventricle. The diagnosis of arrhythmogenic right ventricular dysplasia may be subsequently confirmed by right ventricular angiography or endomyocardial biopsy, both of which are techniques which may not be performed during routine cardiac catheterization in the absence of the radionuclide ventriculography findings to suggest right ventricular dysfunction.