Effects of late administration of tissue-type plasminogen activator on left ventricular remodeling and function after myocardial infarction

Abstract To evaluate the effects of late thrombolysis on left ventricular volume and function in acute myocardial infarction, two-dimensional echocardiography and radionuclide angiography were performed before discharge and after 1 year of follow-up study in 34 patients with acute anterior myocardial infarction. Of these, 10 admitted to the coronary care unit within 4 h from the onset of symptoms were treated with recombinant tissue-type plasminogen activator (rt-PA) (Group A) and 24 admitted between 4 and 8 h after onset were randomly assigned to receive either rt-PA (Group B, n = 12) or conventional therapy (Group C, n = 12). Seven to 10 days after admission, all patients underwent cardiac catheterization and coronary angiography. Patency of the infarct-related vessel was 70% in Group A, 66% in Group B and 33% in Group C and the average Thrombolysis in Myocardial Infarction (TIMI) coronary perfusion grade was 1.9 ± 0.8 for Group A, 1.6 ± 1.0 for Group B and 0.84 ± 0.95 for Group C (Group A versus Group C p At 1 year follow-up study, end-systolic and end-diastolic volumes remained higher in Group C than in Group B (p The beneficial effect of late thrombolysis with rt-PA may be related to a reduction in myocardial expansion and thus to a favorable influence on postinfarction left ventricular remodeling.