title: High prevalence of early repolarization in short QT syndrome.
abstract: BACKGROUND
  Short QT syndrome (SQTS) is characterized by an abnormally short QT interval and sudden death. Due to the limited number of cases, the characteristics of SQTS are not well understood. It has been reported recently that early repolarization is associated with idiopathic ventricular fibrillation and the QT interval is short in patients with early repolarization.
  
  
  OBJECTIVE
  The purpose of this study was to study the association between early repolarization and arrhythmic events in SQTS.
  
  
  METHODS
  The study consisted of three cohorts: SQTS cohort (N = 37), control cohort with short QT interval and no arrhythmic events (N = 44), and control cohort with normal QT interval (N = 185). ECG parameters were compared among the study cohorts.
  
  
  RESULTS
  Heart rate, PR interval, and QRS duration were similar among the three study cohorts. Early repolarization was more common in the SQTS cohort (65%) than in the short QT control cohort (30%) and the normal QT control cohort (10%). Duration from T-wave peak to T-wave end was longer in the SQTS cohort than in the short QT control cohort, although QT and corrected QT intervals were similar. In the SQTS cohort, there were more males among patients with arrhythmic events than in those with a family history but without arrhythmic events. In multivariate models, early repolarization was associated with arrhythmic events in the SQTS cohort. ECG parameters including QT and QTc intervals were not associated with arrhythmic events in the SQTS cohort.
  
  
  CONCLUSIONS
  There is a high prevalence of early repolarization in patients with SQTS. Early repolarization may be useful in identifying risk of cardiac events in SQTS.
authors.affiliation: Division of Cardiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Takeru
authors.initials: T
authors.lastname: Makiyama
authors.forename: Taku
authors.initials: T
authors.lastname: Koyama
authors.forename: Prince J
authors.initials: PJ
authors.lastname: Kannankeril
authors.forename: Shinji
authors.initials: S
authors.lastname: Seto
authors.forename: Kazuki
authors.initials: K
authors.lastname: Okamura
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Oda
authors.forename: Hideki
authors.initials: H
authors.lastname: Itoh
authors.forename: Masahiko
authors.initials: M
authors.lastname: Okada
authors.forename: Naohito
authors.initials: N
authors.lastname: Tanabe
authors.forename: Nobue
authors.initials: N
authors.lastname: Yagihara
authors.forename: Shiro
authors.initials: S
authors.lastname: Kamakura
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Wataru
authors.initials: W
authors.lastname: Shimizu
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D016022:Case-Control Studies; D015331:Cohort Studies; D016001:Confidence Intervals; D000072237:ERG1 Potassium Channel; D004562:Electrocardiography; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics; D005260:Female; D005819:Genetic Markers; D005820:Genetic Testing; D006339:Heart Rate; D006801:Humans; D007564:Japan / Q000453:epidemiology; D051657:KCNQ1 Potassium Channel / Q000235:genetics; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics; D015995:Prevalence; D012307:Risk Factors; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D055815:Young Adult
chemical_list: D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; D005819:Genetic Markers; C489457:KCNJ2 protein, human; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human; D024661:Potassium Channels, Inwardly Rectifying