One-hundred-and-fifty-four consecutive patients were treated with intravenous and intracoronary streptokinase within 3 h of the onset of acute myocardial infarction. Left ventricular function was determined from contrast ventriculograms obtained in the acute phase and at follow-up at 28 (15-37) days in 123 patients with matched ventriculograms. Regional wall motion analysis was performed with a radial axis system and asynergy determined by comparing percentage radial shortening with findings in ten normal controls. Reperfusion was achieved in 79% of patients. However, there was no significant difference in global ejection fraction between the acute phase (60.6%) and follow-up (60.4%) ventriculograms, although a significant reduction of hypokinetic areas was seen. An increase in regional ejection fraction in anterior (+10%) and inferior (+9%) hypokinesis was counterbalanced by a reduction of incidence (-11%) of hyperkinesis and regional ejection fraction (-10%) in the contralateral wall. In patients with a patent infarct-related vessel at follow-up, no difference in global or regional parameters was found in the acute phase, but at follow-up these patients showed improved regional wall motion with an increase in global ejection fraction (1.6%, n.s.). In patients with occluded vessels at follow-up global ejection fraction decreased (-5.4%, P less than 0.05). The decrease of frequency and extent of hyperkinesis in the clinical course of acute myocardial infarction tends to counterbalance recovery of wall motion in the infarcted region, resulting in little change in global ejection fraction.