Benefits and Risks of Intravenous Thrombolytic Therapy With Tissue-Type Plasminogen Activator in Patients With Acute Myocardial Infarction

Tissue-type plasminogen activator (t-PA, 24 million I.U. of alteplase) was administered intravenously to 14 patients with acute myocardial infarction within 6 hours of the onset of symptoms, and its clinical efficacy was evaluated by comparison with 22 untreated controls. Compared with the control group, the patients receiving t-PA had shorter durations of chest pain (7.1±0.9 vs. 11.9±0.7 hr ; p<0.01) and ST elevation (45.4±9.5 vs. 80.5±7.9 hr ; p<0.01). The interval between the onset of symptoms and the maximum creatine kinase level (Max CK) was reduced by treatment with t-PA (16.8±1.5 vs. 22.8±1.6 hr ; p<0.05). Both groups exhibited a similar incidence of ventricular extrasystole and ventricular tachycardia, although patients treated with t-PA required a larger total dose of lidocaine than the control group (11, 401±2, 230 vs. 6, 493±930mg ; p<0.05). During the chronic phase, there were no differences in the patency rate of the infarct coronary artery and the left ventricular ejection fraction in the two groups, but the incidence of ventricular aneurysm was lower in the t-PA group. No serious complications, such as hemorrhage, occurred. Intravenous administration of t-PA combined with appropriate antiarrhythmic therapy appears to be safe and beneficial for acute myocardial infarction.