Failure of early electrocardiogram to predict successful thrombolysis. Effect of stunned myocardium?

We investigated the value of the modified Selvester QRS score in predicting reperfusion in 74 patients with an acute myocardial infarction who were treated with intravenous streptokinase. Coronary angiography and time to peak creatine kinase level were used to determine the success of thrombolytic therapy. At 6 weeks a significant difference was seen between the QRS score of the patients in whom thrombolysis was successful compared with those in whom there was no reperfusion. There was, however, no difference between the QRS score of these groups of patients at 1 week. The ejection fraction at 1 week was 60% and 51%, respectively. The failure of the early electrocardiogram to predict reperfusion and improved left ventricular function may be a consequence of the stunned myocardium.