The predictability of patency of the infarct-related artery assessed by means of three noninvasive easily obtainable markers was prospectively examined in 82 patients undergoing thrombolysis for their first myocardial infarction. Positive noninvasive markers were defined as follows: 1) early peak creatine kinase (CK) activity less than or equal to 12 h after the start of thrombolysis; 2) greater than or equal to 50% reduction in ST segment elevation; and 3) occurrence of reperfusion arrhythmias within the 1st 90 min of thrombolytic therapy. In 63 (77%) of the 82 patients, Thrombolysis in Myocardial Infarction (TIMI) grade II/III reperfusion was achieved within the 1st 90 min as assessed by coronary angiography. Separate analysis of each marker revealed the following respective values for sensitivity, specificity and positive and negative predictive value regarding prediction of coronary artery patency: CK peak less than or equal to 12 h: 84%, 95%, 98% and 64%; reduction of the ST segment elevation greater than or equal to 50%: 60%, 95%, 97% and 42%; and reperfusion arrhythmias: 63%, 89%, 95% and 43%. The combined analysis of all three markers utilizing a logistic regression procedure showed that CK peak (p = 0.0001) and resolution of the ST segment elevation (p = 0.005), but not the occurrence of reperfusion arrhythmias (p = 0.26), were independent predictors of vessel patency. From this logistic regression procedure, a sensitivity of 100%, a specificity of 90%, a positive predictive value of 97% and a negative predictive value of 100% for prediction of coronary artery patency were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)