Comparison of QT Dispersion in Patients with ST-Elevation Myocardial Infarction before and after Treatment by Streptokinase versus Primary Percutaneous Coronary Intervention

Background: QT dispersion (QTD) is a non-invasive ECG marker reflecting myocardial repolarization heterogeneity and arrhythmic risk, particularly in STEMI. Early reperfusion may reduce QTD and improve outcomes. This study aims to compare QTD before and after treatment with streptokinase (SK) versus pPCI in STEMI patients, considering the timing of intervention. Methods: This prospective observational study included 300 STEMI cases admitted to Banha University and El-Sheikh Zayed Specialized Hospitals between September 2023 and April 2024. Cases were stratified into four groups: Group A1 (PCI ≤3 hours), A2 (PCI >3–12 hours), B1 (SK ≤3 hours), and B2 (SK >3–12 hours). All cases underwent ECG, echocardiography, and standard laboratory assessments. QTc dispersion (QTcD) was measured before and 24 hours after reperfusion. Results: Post-treatment QTcD was substantially lower in early PCI group (A1: 21.87 ± 14.89 ms) compared to delayed PCI (A2: 28.05 ± 12.92 ms, p = 0.015), early SK (B1: 24.22 ± 18.87 ms, p = 0.001), and delayed SK (B2: 40.56 ± 15.37 ms, p = 0.001). Group B2 also showed the highest incidence of ventricular tachycardia (VT), ventricular fibrillation (VF), and mortality (p < 0.05). Multivariate analysis identified age, diabetes, anterior STEMI, and delayed presentation as independent predictors of increased QTD. Conclusion: Early reperfusion, particularly via pPCI, is correlated with lower QTD and better clinical outcomes. Delayed treatment and underlying risk factors increase arrhythmic risk, underscoring the need for timely intervention in STEMI patients.