Usefulness of Tp-Te interval and Tp-Te/QT ratio in the prediction of ventricular arrhythmias and mortality in acute STEMI patients undergoing fibrinolytic therapy.

Background And Aim: Acute ST-elevation myocardial infarction (STEMI) is associated with fatal and non-fatal ventricular arrhythmic events (VAE). Although primary percutaneous intervention (PCI) is first-line treatment in STEMI, fibrinolytic therapy (FT) is still widely used in many countries. Tp-Te interval; Tp-Te/QT ratio and QT dispersion (QTd) are novel markers of ventricular repolarization (VR) and associate with VAE and mortality. Hereby, we assessed Tp-Te, QTd and Tp-Te/QT in acute STEMI patients undergoing FT and analyzed their relationship with post-FT VAE, and arrhythmic and overall deaths.

Methods: A total of 207 consecutive STEMI patients treated with FT were retrospectively evaluated. Patients were divided in Group 1 (non-VAE group) and Group 2 (VAE group). ECG, clinical and demographic data were noted. Relationship between the pre-FT electrocardiographic parameters of VR and post-FT VAE, arrhythmic and overall death was evaluated.

Results: Tp-Te, Tp-Te/QT and QTd were significantly higher in Group 2 compared to Group 1 (p < 0.05). Tp-Te, Tp-Te/QT, QTd, QTc and left ventricular ejection fraction (LVEF) predicted VAE. Tp-Te/QT and LVEF predicted arrhythmic death (1.05; 95% CI 1.01-1.08; p = 0.031 and 0.87; 95% CI 0.72-0.96; p = 0.040; respectively). In ROC analysis, cut-off for Tp-Te/QT to predict VAE was >0.305 with 87.5% sensitivity and 60.1% specificity (AUC: 0.90; 95% CI: 0.85-0.95; p < 0.001), and to predict arrhythmic death was >0.315 with 83.3% sensitivity and 62% specificity (AUC: 0.70; 95% CI: 0.60-0.81; p = 0.018).

Conclusion: Tp-Te, Tp-Te/QT, QTc, QTd and LVEF are independent predictors of post-FT VAE in acute STEMI. Tp-Te/QT ratio is associated with VA-related deaths.