To assess the diagnostic value of routine two-dimensional echocardiography in the coronary care unit setting, we studied 81 unselected patients admitted for acute chest pain. Using electrocardiography (ECG), clinical history and serum markers of myocardial injury, the patients were retrospectively diagnosed as having had definite acute myocardial infarction (AMI) with (n=13) or without (n=31) previous infarction, possible AMI with (n=14) or without (n=15) previous infarction, and non-coronary cardiac or other causes of chest pain (n=8). Abnormal wall motion was observed in 75/77 patients with a cardiac origin of symptoms (sensitivity 97%), and there were no false-positive wall motion findings. In the 73 patients who were finally diagnosed with coronary artery disease (CAD), echocardiography showed wall motion abnormality in at least one additional coronary territory area in which there were no diagnostic ECG changes for 56% of patients with CAD (41/73) (P<0. 001). These areas were considered to be indicative of the presence of myocardium at risk for future cardiac events. We conclude that in addition to being a sensitive and accurate tool for detection of ischaemic wall motion abnormalities, two-dimensional echocardiography can give valuable information about the area of myocardium at risk. Therefore, therapeutic decisions can be affected by the findings of the routine echocardiographic examination, which is recommended even in unselected coronary care unit patients.