To evaluate the incidence of silent ischemic heart disease in cerebrovascular patients unable to exercise, we performed intravenous dipyridamole-thallium myocardial imaging in 38 consecutive patients with stroke without angina or previous myocardial infarction. Dipyridamole was injected intravenously at the dosage of 0.56 mg/kg over 4 min, followed by 4 min of handgrip exercise. Of the 38 patients, 35 had severe atherosclerotic lesions of the internal carotid artery and 3 occlusion of the middle cerebral artery. Dipyridamole-thallium myocardial imaging was normal in 15 patients and abnormal in 23 (60%): reversible perfusion defects were detected in 21 cases and fixed defects in 2. Minor side-effects were observed in 5 patients; no neurologic complications occurred. In conclusion, our findings suggest that in a large proportion of patients with severe large-artery occlusive cerebrovascular disease, a silent ischemic heart disease is present. Dipyridamole-thallium myocardial imaging can be proposed as a safe and valuable examination in the noninvasive cardiac screening of those cerebrovascular patients unable to exercise.