Naresh Kumar, Abdul Rehman Abid, Farhan Faisal, Muhammad Imran Farooq, Atif Nazir, Amjad Abrar, Mohsin Nazeer.
Accuracy of ST segment resolution on ECG for success of thrombolysis of infarct related artery in acute myocardial infarction.
J Cardiovascular Dis Jan ;9(1):8-12.

Objectives: To determine the accuracy of ST-Segment resolution on ECG for success of thrombolysis of infarct related artery in acute myocardial infarction taking angiography as gold standard. Materials and Methods: This Cross sectional survey was conducted at the Cardiology Department, Punjab Institute of Cardiology, Lahore from December 2009 to June 2010. One hundred patients of STEMI meeting the criteria were registered in this study. Demographic information including name, age, and sex were obtained. ECG was recorded immediately after the patient arrived in the emergency. ST-Segment elevation was recorded as in 1mm, 2mm, or >2 mm, and infarct related artery (IRA) was identified on ECG. Serial ECGs were analyzed for ST-Segment deviation in terms of ST-Segment elevation and resolution. Streptokinase (SK) injection was given in the standard dose of 1.5 million units over 60 minutes within half an hour of reaching the emergency. The subsequent ECGs were recorded at 90 minutes after the administration of Streptokinase. ST-Segment resolution was recorded as percentage (>50%) resolution of ST-Segment elevation in the same lead. TIMI grade III was considered as success of thrombolysis. Results: Mean age of the patients was 49.14±12.35 years. Out of 100 patients 61(61%) were male and 39 (39%) females. Regarding coronary artery risk factors 47(47%) were Diabetic, 46(46%) hypertensive, 51(51%) smokers, 22(22%) hyperlipidimic, 37(37%) with family history of ischemic heart disease and 17(17%) had previous history of ischemic heart disease. Patients who suffered from anterior wall myocardial infarction were 46(46%), 31(31%) had inferior wall myocardial infarction, 23 (23%) had lateral wall myocardial infarction on their electrocardiogram. Infarct related artery was Left Anterior Dsecending (LAD) in 40 (40%), Left circumflex (LCX) in 29(29%), Right Coronary Artery (RCA) in 24 (24%) and LMS in 7 (7%). ST-segment resolution >50% after 90 minutes of SK administration was observed in 64 (64%). Overall TIMI III flow was observed in 57%. TIMI III flow was in 48% in patients with >50% ST segment resolution and 9% without 50% ST Segment resolution. Measures of diagnostic accuracy were true positive 48%, 16% false positive, 9% false negative and 27% true negative. Thus sensitivity of ST Segment resolution on ECG after SK was 84%, specificity of 62%, positive predictive value was 75% and negative predictive value was 75%. Conclusion: ST resolution on ECG after Streptokinase can predict infarct related artery patency on coronary angiography. ST Segment resolution on ECG has moderate sensitivity and specificity in detection of TIMI III flow in infarct related artery. Key Wors: Acute ST-segment elevation myocardial infarction, myocardial territory, culprit coronary artery, stenosis severity.

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