Accuracy of Resolution of ST-Segment Elevation in Electrocardiogram to Determine the Patency of Infarct-Related Artery

Introduction: There is very limited data comparing the accuracy of ECG to angiography in predicting reperfusion status. In this study, we will determine the accuracy of ECG change i.e. resolution of ST-segment elevation in predicting infarct-related artery (IRA) patency after thrombolysis in patients with ST-segment elevated myocardial infarction (STEMI), in comparison to angiography. Methods: Three hundred and forty-one (n = 341) patients with acute STEMI received streptokinase, a thrombolytic agent within 12 hours of symptoms, and were enrolled in the study via consecutive convenient non-probability sampling. ECG was recorded as soon as the patient arrived in the emergency unit of cardiology. Subsequent ECG was recorded three hours after the administration of streptokinase to look for resolution of ST-segment elevation. ST-segment resolution was classified as greater/equal to 50% resolved or less than 50% resolved. Coronary angiography was performed within 24 hours of hospitalization and flow in the IRA was assessed. Results: The most common site of myocardial infarction (MI) was the anterior wall (50.1%) and the commonest artery involved was the left anterior descending artery (44.2%). On ECG, ST-resolution of more than 50% was found in 242 (70.9%) participants. Thrombolysis in MI (TIMI) grade III flow in angiography was found in 211 (61.8%) participants. The sensitivity and specificity of ST-resolution to detect TIMI grade III flow was 94.79% and 67.69%, respectively, while accuracy was 84.46%. Conclusion: ST-resolution on ECG after streptokinase can predict IRA patency on coronary angiography with moderate to good accuracy. ECG can assist in predicting the impact of streptokinase early in the course of management and give an option of monitoring patient prognosis with a non-invasive test in patients not comfortable with angiography.