title: Variability of Myocardial Repolarization in Pediatric Patients with a Ventricular Septal Defect.
abstract: In patients with a ventricular septal defect, left-to-right shunting increases the left ventricular preload. This pathological change affects myocardial depolarization and repolarization and has the potential to evoke arrhythmogenic substrates. We examined the effect of ventricular septal defects on myocardial repolarization by investigating the variability in the repolarization interval. This retrospective study included 19 patients (mean age, 1.8 ± 2.1 years) who underwent surgical closure (mean left-to-right shunt ratio, 2.60 ± 0.55) and 26 age-matched healthy controls from 2008 to 2015. Using preoperative electrocardiograms, we studied two electrocardiographic parameters (heart rate-corrected repolarization and variability of repolarization) and four repolarization intervals (QT, JT, J point to T peak [JTp], and T peak to T end [Tp-e] intervals). The variability index (VI) was calculated from the logarithm of the ratio of the repolarization parameter variance to heart rate variance. The various measures were compared between the patients and controls, and significant differences were found in the corrected QT, JTp, and Tp-e intervals (p < 0.05). The VI of the four intervals also showed significant differences (patients vs.
  
  
  METHODS
  QTVI, -0.55 ± 0.61 vs. -1.10 ± 0.53; JTVI, -0.33 ± 0.60 vs. -0.86 ± 0.57; JTpVI, -0.15 ± 0.78 vs. -0.73 ± 0.56; Tp-eVI, 0.75 ± 0.70 vs. 0.11 ± 0.73, respectively; p < 0.05). No correlation was found between the QTVI and corrected QT interval using linear regression analysis. These repolarization characteristics provide not only electrophysiological indices but also a new index with which to assess the pathophysiology of congenital heart disease.
authors.affiliation: Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Uchida
authors.affiliation: Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Nishio
authors.affiliation: Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Omeki
authors.affiliation: Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Takeuchi
authors.affiliation: Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Rina
authors.initials: R
authors.lastname: Nagata
authors.affiliation: Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Oikawa
authors.affiliation: Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan.
authors.forename: Arisa
authors.initials: A
authors.lastname: Nagatani
authors.affiliation: Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Eryu
authors.affiliation: Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan. thata@fujita-hu.ac.jp.|Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan. thata@fujita-hu.ac.jp.
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Hata
authors.affiliation: Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan.
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Yoshikawa
mesh_terms: D001145:Arrhythmias, Cardiac; D002675:Child, Preschool; D004562:Electrocardiography; D006329:Heart Conduction System; D006339:Heart Rate; D006345:Heart Septal Defects, Ventricular; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012189:Retrospective Studies
keywords: J point to T peak interval; QT interval; Repolarization characteristics; T peak to T end interval; Ventricular septal defect