Left ventricular diastolic function was studied by Doppler echocardiography in 35 patients with non-Q-wave myocardial infarction, on the third and tenth day of hospitalization and six weeks after hospitalization and was correlated with electrocardiogram, serum enzyme values, and angiographic data. Normal diastolic function on the first echocardiographic study predicted (p = 0.0001) the existence of no or single-vessel disease, and excluded (p = 0.005) the presence of 3-vessel or left main disease, whereas an abnormal study on either the second or third echocardiographic discriminated (p = 0.0001), with higher sensitivity (80.97%, 92.31%, respectively), patients with 3-vessel or left main vessel disease.