Background: Atrioventricular nodal reentry tachycardia (AVNRT) is known to be associated with increased risk of susceptibility for ventricular arrhythmias and sudden death. Studies indicate that prolongation of the interval between the peak and end of the T wave (Tpeak to Tend, Tp-e) on the 12-lead ECG, is a marker of ventricular arrhythmogenesis. The aim of this study was to assess ventricular repolarization in patients with AVNRT by using Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio.
Method: Patient records were retrospectively analyzed. Electrocardiogram of 62 patients, who were diagnosed as AVNRT by electrophysiological study, were obtained and scanned. T wave peak to end interval, QT and corrected QT intervals were measured. Electrocardiograms of age and sex matched 34 healthy control individuals were also analyzed for comparison. Patients with critical coronary stenosis, moderate or severe valve disease, left and/or right heart failure, left and/or right ventricle hypertrophy, atrial fibrillation, right or left bundle block or patients who got pacemaker or ICD implanted were excluded.
Results: Both groups did not differ in patient demography. Mean values for AVNRT patients and control group were: QT (362.7±43.7 vs 364.1± 34.1), QTc (417.8±43.2 vs 438.3±44.2) and Tp-e interval (83.5±16.6 vs 77.0±9.7). Tp-e/QT and Tp-e/QTc ratio were also higher in AVNRT group.
Discussion: Tp-e is a measure of transmural dispersion of repolarization in the left ventricle and accepted as a surrogate for increased ventricular arrhythmogenesis risk. Tp-e/QT and Tp-e/QTc are relatively new markers which also indicate repolarization defects. Our results show that Tp-e (p=0.018), Tp-e/QT (0.23 vs 0.21; p=0,008) and Tp-e/QTc (0.20 vs 0.17; p=0.000) were significantly higher in AVNRT group which correspond to prior studies about strong relationship between AVNRT and ventricular arrhythmia.