RESUMO
BACKGROUND: QT dispersion (QTD) represents inhomogeneous ventricular repolarization such that an increased QTD may predispose the heart to malignant ventricular arrhythmias (VAs). This study was conducted to compare QTD in patients with ST-elevation myocardial infarction (STEMI) before and after treatment by streptokinase (SK) versus primary percutaneous coronary intervention (PCI). METHODS: The present case-control study was conducted on 185 STEMI patients who received SK (115 cases) or underwent primary PCI (70 cases). QTD and QT corrected dispersion before and 24 h after treatment. Likewise, they were also found to correct fatal arrhythmias (VT and VF) during the first 24 h after admission, and ejection fraction (EF) 24 h after treatment was evaluated. RESULTS: QTD decreased in the primary PCI group, though no significant difference was seen between the two studied groups (P > 0.05). A significant increase was detected in the EF mean values for the primary PCI-treated patients (P = 0.022). Moreover, there was a significant reduction in QTD of patients with fatal arrhythmias in the primary PCI group (P = 0.022). CONCLUSION: An overall QTD reduction in the primary PCI group and a significant decrease in QTD of patients with fatal arrhythmias in the primary PCI group show that this treatment strategy is more efficient than thrombolytic therapy. As an important indicator of proper myocardial function, EF can independently predict improved myocardial function in the primary PCI group.