Results of recent studies have suggested that routine cardiac catheterization may be unnecessary after reperfusion therapy for acute myocardial infarction. Therefore to better define the short-term prognostic value of early coronary angiography, and specifically the prognostic significance of multivessel coronary artery disease, the angiographic findings of 855 patients consecutively enrolled in five phases of the TAMI study were correlated with their in-hospital outcome. All patients received intravenous thrombolytic therapy (tissue plasminogen activator, urokinase, or both agents) and underwent cardiac catheterization within 90 minutes of the initiation of therapy. Multivessel disease, defined as the presence of greater than or equal to 75% luminal diameter stenosis in two or more major epicardial arteries, was documented in 236 patients. When compared with the group of patients without multivessel disease, this group had a higher prevalence of coronary risk factors and more frequently had a history of antecedent ischemic chest pain. Although the severity of the infarct zone dysfunction was similar in the two groups (-2.77 +/- 1.00 vs -2.50 +/- 1.09 SD/chord, p = NS), global left ventricular ejection fraction was lower in the group with multivessel disease (48.6 +/- 12.4% vs 51.8 +/- 10.6%, p less than 0.01). This was associated with a significant difference in the function of the noninfarct zone. Whereas this region was hyperkinetic in the group with minimal or single-vessel disease, it was hypocontractile or dyskinetic in those with multivessel disease (+0.66 +/- 1.53 vs -0.52 +/- 1.73 SD/chord, p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)