Resolution of ST-segment elevation after streptokinase therapy in anteriorversus inferior wall myocardial infarction

Background: Resolution of ST-segment elevation is the best bedside predicto r of myocardial reperfusion. Hypothesis: This study was conducted to examine the resolution of ST-segmen t elevation after streptokinase therapy in anterior versus inferior acute m yocardial infarction (MI) and to corroborate it with echocardiographic and coronary angiographic data. Methods: The study population consisted of 70 patients, 35 each in the ante rior and inferior MI groups. The electrocardiograms (ECGs) were recorded be fore, on completion of, and on Days 1 and 2 post streptokinase therapy. The resolution of ST segment determined from post-streptokinase ECGs was compa red between the two groups and correlated with echocardiographic and corona ry angiographic data. Results: On completion of and on Day 1 post streptokinase therapy, ST-segme nt resolution in both groups was not significantly different. On Day 2 post streptokinase therapy, resolution of the ST segment per lead was significa ntly lower in anterior than that in inferior MI (61 +/- 21% anterior vs. 77 +/- 21% inferior, p 0.003). The number of patients with akinesis of infarc t-related ventricular wall was significantly higher (17 anterior vs. 7 infe rior, p 0.02), and left ventricular ejection fraction was significantly low er in anterior MI (39 +/- 7% anterior vs. 48 +/- 8% inferior, p < 0.01). Th ere was no significant difference in coronary angiographic data. One patien t in each group demonstrated normal coronary arteries. Conclusions: The resolution of ST-segment elevation on the completion of an d on Day 1 post streptokinase therapy was comparable between anterior and i nferior MI. The significantly less frequent resolution of ST-segment elevat ion in anterior MI on Day 2 post streptokinase could be due to more akinesi s, larger infarct size, and worse systolic function rather than due to fail ure to open the infarct-related vessel.