To Study the Accuracy of ECG in Localizing the Site of Occlusion in Acute STEMI and its Angiographic Correlation.

Abstract

Background: This study has been designed to localize the site of occlusion in acute STEMI ( ST elevation MI) , by ECG findings according to the various algorithm and to correlate it with coronary angiographic findings and fill gaps in the literature from the Indian population. Methods: Patients of STEMI presenting within 12hours from the onset of symptoms were included in this study. Relevant clinical and biochemical laboratory parameters such as lipid profile, cardiac markers were obtained from the patients. Coronary angiography was performed to detect the culprit lesion as significant stenosis (>70%) in the coronary artery. The aim is to study the electrocardiographic profile of the patients and relate it with angiography findings.
Results: 160 patients who fulfilled the inclusion criteria were enrolled in the study. The main culprit artery was found to be LAD ( Left anterior descending ) 89 (55.6%), followed by RCA ( right coronary artery )53 (33.1%) and LCx (Left circumflex) 18 (11.3%). The angiography findings showed dominant circulation as RCA 135 (84.4%) and LCx 15 (9.4%). The angiography revealed four patients had no lesion while lesions in LAD were observed in 85 (53.1%) patients, RCA in 52 (32.5%), and LCx in 19 (11.9%). The ECG findings using
FIOL’s algorithm for LAD occlusion site proximal to D1 ( diagonal) showed 70.31% sensitivity, 88% specificity, positive predictive value 93.75%, and negative predictive value 53.66%. . The sensitivity, specificity, PPV ( positive predictive value) and NPV ( negative predictive value) of ECG based findings for culprit artery against coronary angiography using various algorithm showed 100% sensitivity, 94.67%
specificity, 95.51% PPV and 100% NPV for LAD, 94.23% sensitivity, 96.30% specificity, 92.45% PPV and 97.20% NPV for RCA, and 89.47% sensitivity, 98.58% specificity, 89.47% PPV and 98.58% NPV for LCx.
Conclusion: There is a good correlation between ECG changes in the acute phase of MI with ST elevation and the affected myocardial zone and the location of the occluded artery. The careful ECG analyses can help in making a decision to recommend an urgent PTCA (percutaneous transluminal coronary angioplasty).