Ventricular tachycardia was noted in 4 members of the same family. One showed diffuse hypokinesis of the left ventricle by echocardiography and left ventriculography, 2 showed progressive left ventricular dysfunction and 1 showed regional perfusion defects of the left ventricle shown by thallium scintigraphy. One patient was diagnosed as dilated cardiomyopathy. Although no definitive cause of the left ventricular disturbance was identified in the 3 other patients, they may have all been dilated cardiomyopathy.