Influence of vessel involvement and early streptokinase therapy on regional and global left ventricular function in acute myocardial infarction.

150 consecutive patients with acute myocardial infarction received 750,000 units of intravenous streptokinase within four hours of pain onset. Angiography was performed on day 6, from which ejection fraction (EF), infarct-related ejection fraction (IREF), and non-infarct related ejection fraction (NREF) were calculated. 50% stenosis was considered to be significant. The streptokinase patients with patent infarct-related arteries who had no evidence of previous myocardial infarction were compared with 82 conventionally treated (without streptokinase) patients who had no evidence of previous myocardial infarction. Sub-group analysis based on vessel involvement, usage and timing of streptokinase was done. Streptokinase was associated with better left ventricular function in all sub-groups if given less than 2 hours after pain onset. In inferior myocardial infarction, streptokinase patients with single-vessel disease had normal EF (67 +/- 8), compared to significantly depressed EF in multi-vessel disease (56 +/- 12, p less than 0.05). This difference is accounted for more by the NREF than the IREF. In anterior infarction, patients with single-vessel disease did only slightly better than multi-vessel disease. In multi- and single-vessel anterior infarction, preservation of function by streptokinase appears to be due to the compensatory ability of the non-infarcted region as well as the residual function of the infarct-related region. region.