Continuous ST- and QRS-vector changes and myoglobin release during streptokinase-treated acute myocardial infarction

Twenty-two consecutive patients with a first myocardial infarction treated with streptokinase (SK) were compared to a group of 33 consecutive patients who did not receive SK. Age, infarct localization, duration of symptoms and infarct size, as estimated by cumulative creatine kinase (CK) release, did not differ between the two groups. Myoglobin (MG) release stopped after 5.5 +/- 3.3 h in SK-treated patients, which was 11 h earlier than in the controls (P less than 0.0001). CK release ceased after 15 +/- 7.8 h, about 13 h earlier than in the controls (P less than 0.0001). ST and QRS vector changes, registered by continuous vectorcardiography, were completed after 2.9 +/- 2.0 and 4.4 +/- 2.5 h respectively, about 2 and 4 earlier than in the controls (P less than 0.005 and P less than 0.0001 respectively). With SK, the termination of ST and QRS vector changes occurred more uniformly than corresponding vector changes in the controls, in whom a longer time interval between the termination of ST and the end of QRS vector changes was observed. With SK, the difference between the end of ST and QRS vectors decreased by about 3 h to 1.6 +/- 1.5 h (P less than 0.0001). Temporal relations between MG release and ST and QRS vector changes were similar but more uniform than in those of the reference group. In conclusion, we found that SK resulted in an accelerated and more uniform development of the infarct process, ending about 10 h after onset of therapy, compared with 20-30 h in the reference group.