In 314 patients with a first myocardial infarction, admitted within four hours after development of symptoms, the authors used in addition to standard therapy heparin treatment in 205 and streptokinase treatment (1.5 mil. u. i.v. with subsequent i.v. heparin administration) in 109 patients. Thrombolytic treatment was more effective, it reduced the lethality by 55.7% and was associated with a lower incidence of complications during the first 30 days. The reduced lethality, however, did not reach statistical significance because of the small number of patients and the low mortality rate in both groups. The left ventricular ejection fraction was practically equal in both groups after six weeks. Undesirable effects of thrombolytic therapy were rare and did not seriously threaten the patients. Provided contraindications are carefully respected, this treatment is safe and its routine use in the treatment of new myocardial infarctions must be supported. Streptokinase remains the drug of choice because it is equally effective as other available fibrinolytics and is the cheapest one.

Keywords: Adult; Aged; Female; Humans; Injections, Intravenous; Male; Middle Aged; Myocardial Infarction /drug therapy/; Prospective Studies; Streptokinase /administration & dosage/; Stroke Volume; Thrombolytic Therapy /adverse effects/