Using guide-wires and special catheters the occluded infarct-related coronary artery was recanalized in 10 patients with acute myocardial infarction 6.6 +/- 7.1 hours after the onset of symptoms. There were no complications. Immediately after recanalization there were 80-95% lesions at the site of the previous occlusion. Angiography, performed in 9 patients in the chronic stage of myocardial infarction, revealed patency of the recanalized vessel in all instances. There was a marked decrease in the narrowing at the time of the second angiogram in 6 patients. Changes in left ventricular function from the acute to the chronic stage were assessed in 8 patients: the ejection fraction increased in 6. The results of this pilot study indicate that transluminal recanalization of acutely occluded coronary arteries is possible without harmful side-effects. Early restoration of flow may salvage the jeopardized myocardium. Further application of this method of treatment in selected patients and efforts to improve the technique seem to be justified.