Potential sources of emboli in patients with presumed transient cerebral or retinal ischaemia.

Potential sources of emboli were sought by non-invasive techniques and, where appropriate, by angiography in 117 consecutive patients referred to a neurological service with symptoms of transient cerebral or retinal ischaemia. The non-invasive tests were also applied to 104 age and sex matched controls. 32% of the patients had structural cardiac abnormalities, 32% had arrhythmias on 24 h electrocardiographic monitoring, 15% had evidence of ischemic heart disease, and 34% were or had been hypertensive. The proportions of these abnormalities in the control group were 14%, 28%, 12%, and 10%, respectively. 37% of the patients who had carotid angiograms had significant arterial lesions. Some patients had both cardiac and carotid lesions but 25% of the patients who had complete investigations had no detectable evidence of any cardiovascular disease.