The aim of this study was to evaluate the usefulness of dobutamine echocardiography (DE) in distinguishing necrotic from ischemic myocardium in infarct zones. We performed DE in 39 patients, 3 to 5 days after admission for a first, acute myocardial infarction, treated with thrombolysis. DE was considered positive if wall motion in the infarct zone worsened progressively during increasing dose of dobutamine or if wall motion in the infarct zone initially improved at low dose of dobutamine and deteriorated at higher dose. The results of DE were correlated to the evolution of wall motion in the infarct zone after 3 months and to the need for supplementary balloon dilatation. In 15 of the 39 patients, there was evidence of residual ischemia in the infarct zone. Twenty of the 39 patients had a positive dobutamine echocardiogram. Eleven of these 20 patients had evidence of residual ischemia in the infarct zone. They showed generalized changes of wall motion in the total infarct territory during DE. The other 9 patients demonstrated only localized changes of wall motion in isolated segments of the infarct zone during DE. None of these patients had evidence of residual ischemia. CONCLUSIONS DE seems worthwhile in the detection of residual ischemia in the region of infarction. To reduce the number of false positive DE early after myocardial infarction, only extensive changes of wall motion in the total infarct territory should be accepted as indicative of residual ischemia in the infarct zone.