Coronary artery disease (CAD) poses a significant health burden in India, and ST-elevation myocardial infarction (STEMI) is one of its most severe manifestations. The electrical activity is variable during STEMI, which produces dispersion and raises the T Peak-T End (Tp-Te) interval. STEMI is a medical emergency that requires prompt intervention to restore blood flow to the affected part of the heart muscle. Timely diagnosis and treatment are crucial in reducing morbidity and mortality associated with STEMI. Despite advancements in medical care, access to timely intervention and appropriate healthcare facilities remains a challenge in many parts of India, especially in rural areas. This single-center, prospective observational study included 150 STEMI patients. Clinical, demographic, and ECG data were recorded. The Tp-Te interval alterations and their relationship to major adverse cardiovascular events (MACE) in STEMI patients both during and after successful or unsuccessful fibrinolysis were examined. Patients without MACE had a significant mean decrease in the Tp-Te interval following successful fibrinolysis (i.e., 18.47 ± 5.66 ms vs. 10 ± 7.07 ms, p:0.039) compared to patients with MACE. It was found that after fibrinolysis, patients with a Tp-Te interval > 100 ms experienced much higher rates of death (4% vs. 0%, p:0.0001), arrhythmias (7.3% vs. 0.7%, p:0.0001), and heart failure (16% vs. 1.3%, p:0.0001), both while they were in the hospital and within 30 days of the index event. Our data shows that a decrease in the Tp-Te interval following fibrinolysis lowers the risk of MACE both during hospital stay and within 30 days following the index incident.