title: Relationship between Neurocardiogenic Syncope and Ventricular Repolarization.
abstract: BACKGROUND
  We aimed to analyze ventricular repolarization in neurocardiogenic syncope (NCS) patients by using T-peak-T-end interval, T-peak-T-end/QT ratio, T-peak-T-end/QTc ratio and corrected QT interval (QTc), QT dispersion (QTd), QT index (QTI) and corrected QT interval index (QTcI) comparing with the corrected JT dispersion (JTcd), and corrected JT (JTc) and the corrected JT interval index (JTcI), by inspecting ventricular activation until termination of repolarization. These parameters are used as an index of potential ventricular arrhythmogenesis.
  
  
  METHODS
  We have studied patients with head-up tilt table test (HUTT) (+) (33 patients; mean age: 28 ± 11 years) and HUTT (-) as control group (33 patients; mean age: 30 ± 11 years). In all patients, T-peak-T-end interval, T-peak-T-end/QT ratio, T-peak-T-end/QTc ratio, QT, QTd, QTI, QTc, QTcI, JTd, JTc, and JTcI were measured on electrocardiogram.
  
  
  RESULTS
  The following parameters were statistically significant between groups: QTd (22.72 ± 17.54 msn; 11.21 ± 13.40 msn; P = 0.004), QTc (424.27 ± 33.75 msn; 403.66 ± 38.08 msn; P = 0.023), QTcI (114.09 ± 14, 29%; 106.71 ± 15.33%, P = 0.047), and QTI (100.72 ± 7.19%; 97.14 ± 7.13%, P = 0.046). Furthermore, T-peak-T-end interval was significantly prolonged in the study group (93.78 ± 20.27 msn; 81.21 ± 11.66 msn; P = 0.003). T-peak-T-end/QT ratio was significantly higher in the study group (0.24 ± 0.04 msn; 0.22 ± 0.04 msn; P = 0.030). T-peak-T-end/QTc ratio was significantly higher in the study group (0.22 ± 0.04 msn; 0.20 ± 0.03 msn; P = 0.015). The JTc and JTd were also significantly higher in the study group ([103.00 ± 9, 72%; 95.44 ± 10.26%, P = 0.003], [27.57 ± 16.01 msn; 10.45 ± 16.08 msn; P < 0.001], respectively).
  
  
  CONCLUSIONS
  Electrocardiographic ventricular repolarization parameters including T-peak-T-end interval, T-peak-T-end/QT ratio, T-peak-T-end/QTc ratio, QTc, QTd, QTI, QTcI, JTc, JTd, and JTI are prolonged in NCS.
authors: Electrophysiology Division, Cardiology Department, Gaziantep University, Gaziantep, Turkey.
authors: Murat
authors: M
authors: Sucu
authors: Orhan
authors: O
authors: Ozer
authors: Vedat
authors: V
authors: Davutoglu
authors: Suleyman
authors: S
authors: Ercan
authors: Murat
authors: M
authors: Yuce
authors: Fatma Yilmaz
authors: FY
authors: Coskun
mesh_terms: D000328:Adult; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D019462:Syncope, Vasovagal / Q000503:physiopathology*; D018667:Tilt-Table Test
keywords: electrocardiogram; neurocardiogenic syncope; repolarization