Background:Early identification is crucial, as evidenced by the high mortality rate linked to ACS. The present study was conducted to assess positive T-wave in lead aVR and major adverse cardiac events in patients with ST elevation myocardial infarction. Materials & Methods:92 patients with STEMI of both genders were divided into two groups based on the presence of a positive T wave (Group I) and a negative T wave (Group II) in lead aVR. Assessments of cardiac biomarkers such as troponin levels, creatinine kinase (CK), and CKMB, as well as lipid profiles, renal function, and other factors associated with myocardial infarction, were part of the laboratory studies. During their in-hospital stay, patients were monitored for MACE. Results:In group I and group II, haemoglobin (gm%) was 13.4 and 13.8, white blood cells (109/L) was 13567.3 and 11235.8, pulse rate (beats per minute) was 86.2 and 87.4, systolic blood pressure (mmHg) was 110.2 and 109.4, Troponin I was 11.7 and 21.6, CK-MB was 81.4 and 68.3, creatinine was 1.4 and 0.81 and left ventricular ejection fraction (<40%) was seen in 31 and 25 respectively. The difference was significant (P< 0.05). V3, V4 (Anterior wall STEMI) was observed in 31% and 28%, V3, V4, I, AVL, V5, V6 (Antero-lateral wall STEMI) in 0 and 9%, V1, V2, V3, V4 (Antero-septal wall STEMI) in 25% and 17% and II, III, AVF (Inferior wall STEMI) in 44% and 46% in group I and II respectively. The difference was non- significant (P> 0.05). MACE was Arrhythmia in 18% and 5%, cardiogenic shock in 52% and 42%, pulmonary oedema in 65% and 37%, heart failure in 54% and 32%, deaths in 13% and 8% in group I and group II respectively. The difference was significant (P< 0.05). Conclusion: In cardiology, a positive T wave in lead aVR is more significant than is now understood. Among study participants with a positive T wave in lead aVR on the ECG, there is an increased risk of significant adverse cardiac events during hospitalization, including heart failure, pulmonary oedema, cardiogenic shock, and death. Consequently, in-hospital MACE in patients with a STEMI diagnosis can be predicted using the positive T wave in lead aVR.