Radionuclide angiography phase analysis was performed in two patients presenting with recurrent right-sided ventricular tachycardia without angiographic evidence of valvular or ischemic heart disease. A dilated, poorly contracting (EF = 20%) right ventricle with localized dyskinetic areas was found in contrast with normal left ventricular function. The suggested diagnosis of Arrhythmogenic Right Ventricular Dysplasia was confirmed by right ventricular angiography performed in one patient. The diagnostic interest of radionuclide angiography phase analysis in patients with Arrhythmogenic Right Ventricular Dysplasia is stressed.