LONG-TERM EFFECTS OF ACUTE THROMBOLYTIC THERAPY ON VENTRICULAR SIZE AND FUNCTION

To investigate the influence of thrombolytic therapy on the natural hi story of left ventricular size and regional function after myocardial infarction, 32 patients treated with acute thrombolytic therapy (treat ment group) were studied by echocardiography on admission to the hospi tal and at 1 week, 3 months, and 1 year after myocardial infarction; t hey were compared with 40 patients who did not receive acute intervent ion (control group). The endocardial surface area index (cm2/m2) and t he area of abnormal wall motion (cm2) were calculated from left ventri cular dimensions and measurements of abnormal wall motion. Although no differences in the endocardial surface area index were noted over the year for the groups as a whole, a significant difference was noted in treated anterior infarctions with early functional infarct expansion compared with untreated infarct expansion (treatment group: 85.8 +/- 2 .0 cm2/m2 [entry] to 77.4 +/- 2.7 cm2/m2 [1 week] to 69.9 +/- 4.2 cm2/ m2 [3 months] to 67.2 +/- 6.4 cm2/m2 [1 year] versus control group: 84 .0 +/- 6.4 cm2/M2 [entry] to 83.7 +/- 8.5 cm2/m2 [1 week] to 96.3 +/- 8.6 cm2/m2 [3 months] to 81.5 +/- 4.2 cm2/m2 [1 year]; p < 0.01). When early expansion was present, those receiving thrombolysis exhibited a consistent decrease in the initially enlarged endocardial surface are a in contrast to control subjects, who demonstrated continued increase s in endocardial surface area during the first 3 months. In all groups a decrease in the area of abnormal wall motion was observed during th e year of follow-up. However, the magnitude and timing of the improvem ent was accelerated in the treatment group. Thus acute thrombolytic th erapy alters the natural history of left ventricular size and function with a more rapid recovery of abnormal endocardial segments and rever sal of functional infarct expansion.