Correlation between ST-Segment regression and infarct-related artery patency in acute myocardial infarction

ABSTRACT

The need for an immediate and accurate assessment of the success of thrombolysis in acute myocardial infarction [AMI] is invaluable. The aim of this study was to assess the usefulness and accuracy of the rate of ST segment regression in detecting reperfusion after thrombolytic therapy in the setting of AMI. Forty patients [35 males and 5 females] with a first AMI were included. Their mean age was 47.4 +/- 8 years. All patients received 1.5 million units of streptokinase. Coronary angiography was performed for all patients within 24 hours from the time of initiation of therapy. The TIMI criteria was used for grading the perfusion of the infarctrelated artery [IRA]. A 12- leads ECG was done on admission, immediately after streptokinase [60 minutes from the start of therapy] and 4 hours after streptokinase. Rapid ST segment regression was defined as >/= 50% regression of the total score of ST segment elevation in leads showing the infarction. According to the result of coronary angiography, the patients were subdivided into 2 groups Group P [n = 23] patients with a patent IRA and Group O [n = 1 7] those with occluded IRA. The mean percent of ST segment regression at 60 minutes after streptokinase was significantly lower in group P [56 +/- 13%] than group O [30.4 +/- 8%] [P < 0.05]. Among the 23 patients in group P, 17 had >/= 50% ST regression at 60 minutes and 6 had < 50% [sensitivity 74%]. Among the 17 patients in group O, 14 had < 50% ST regression and 3 had >/= 50% [specificity 82%]. Thus ST segment regression showed good correlation with IRA potency in the setting of AMI and can be used as a reliable indicator of success of reperfusion