Late thrombolysis followed by antithrombotic treatment in acute myocardial infarction: effect of therapy evaluated with thallium-201 SPECT.

Perfusion abnormalities and infarct size evaluated by thallium-201 SPECT after late thrombolysis followed by anti-thrombotic treatment in acute myocardial infarction were studied in 111 patients. Patients were prospectively randomized to a treatment group (n = 54) receiving streptokinase initiated 12-49 h after onset of symptoms, followed by heparin for at least 5 days and warfarin and dipyridamole for at least 3 months, or to a control group (n = 57) treated routinely without any of these drugs. Thallium-201 scintigraphy was performed within 3 months of follow-up in 40 (74%) of the patients in the treatment group and 46 (81%) in the control group. During a symptom-limited bicycle test the isotope was injected at peak exercise. SPECT was acquired 10 min later (exercise SPECT) and after 3 h (redistribution SPECT). A computerized quantitative analysis was performed. Defects were defined as regions with activity below 40% of the maximum. In the exercise SPECT defects were significantly smaller in the treatment group than among control patients (9 +/- 12% vs 15 +/- 15% of the left ventricle; P < 0.05). The difference was more apparent in patients with Q-wave than in those with non-Q-wave infarctions and the entire difference was accounted for by patients without a previous history of infarct or angina pectoris. There was no statistically significant difference in defect size in the redistribution SPECT (5 +/- 10% vs 9 +/- 11%, ns).(ABSTRACT TRUNCATED AT 250 WORDS)