title: Seasonal variability of QT dispersion in healthy young males.
abstract: BACKGROUND
  There are few data related to the seasonal influences on the QT dispersion.
  
  
  METHODS
  We analyzed the effects of seasons on QT dispersion in a large group of healthy young males. We studied the seasonal variability of QT dispersion in 523 healthy male subjects aged 22 +/- 4 years (ranging from 20 to 26). Four seasonal 12-lead resting electrocardiograms (ECGs) recorded at double amplitude were performed at 25 mm/s at intervals of 3 months. Subsequent ECGs were recorded within 1 hour of the reference winter recording. QT dispersion was defined as the difference between the longest and the shortest mean QT intervals.
  
  
  RESULTS
  There was a significant seasonal variation in QT dispersion (P = 0.001), with the largest QT dispersion in winter (71 +/- 18 ms) and the smallest one in spring (43 +/- 19).
  
  
  CONCLUSIONS
  There exists a significant seasonal variation in QT dispersion of healthy subjects and such variability should be taken into consideration in the evaluation process of QT dispersion.
authors.affiliation: Department of Cardiology, Gülhane Military Medical Academy, Ankara, Turkey Department of Cardiology, Hacettepe University School of Medicine, Ankara, Turkey. aiyisoy@hotmail.com
authors.forename: Sedat
authors.initials: S
authors.lastname: Kose
authors.forename: Kudret
authors.initials: K
authors.lastname: Aytemir
authors.forename: Ilknur
authors.initials: I
authors.lastname: Can
authors.forename: Atilla
authors.initials: A
authors.lastname: Iyisoy
authors.forename: Hurkan
authors.initials: H
authors.lastname: Kursaklioglu
authors.forename: Basri
authors.initials: B
authors.lastname: Amasyali
authors.forename: Ayhan
authors.initials: A
authors.lastname: Kilic
authors.forename: Ersoy
authors.initials: E
authors.lastname: Isik
authors.forename: Ali
authors.initials: A
authors.lastname: Oto
authors.forename: Ertan
authors.initials: E
authors.lastname: Demirtas
mesh_terms: D000328:Adult; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008297:Male; D010507:Periodicity; D012621:Seasons