title: Increased QT variability in patients with anorexia nervosa--an indicator for increased cardiac mortality?
abstract: OBJECTIVE
  Increased mortality in anorexia nervosa is associated with autonomic dysfunction and prolongation of the QT interval. In this study, we examined the relative importance of repolarization abnormalities and vagal modulation of heart rate. In particular, we hypothesized that patients with anorexia nervosa show increased QT interval variability, particularly since this measure has been shown to correlate with serious cardiac arrhythmias.
  
  
  METHODS
  We assessed linear and nonlinear heart rate variability (HRV) parameters as well as measures of QT variability in 20 female patients with anorexia nervosa and 20 controls. In patients, parameters were correlated with serum electrolytes.
  
  
  RESULTS
  QT variability was significantly increased in the patient group and correlated negatively with serum potassium concentrations. HRV measures showed a shift of autonomic balance towards vagal predominance.
  
  
  CONCLUSIONS
  The increase in QT variability might at least in part account for the higher risk of cardiac arrhythmias in patients with anorexia nervosa. Once validated in a prospective study design, parameters of QT variability might serve as surrogate markers for arrhythmia risk stratification in anorexia nervosa. Supplementation with potassium might normalize QT variability abnormalities.
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital, Jena, Germany.
authors.forename: Mandy
authors.initials: M
authors.lastname: Koschke
authors.forename: Michael K
authors.initials: MK
authors.lastname: Boettger
authors.forename: Claudia
authors.initials: C
authors.lastname: Macholdt
authors.forename: Steffen
authors.initials: S
authors.lastname: Schulz
authors.forename: Vikram K
authors.initials: VK
authors.lastname: Yeragani
authors.forename: Andreas
authors.initials: A
authors.lastname: Voss
authors.forename: Karl-Jürgen
authors.initials: KJ
authors.lastname: Bär
mesh_terms: D000293:Adolescent; D000328:Adult; D000856:Anorexia Nervosa / Q000150:complications / Q000401:mortality* / Q000503:physiopathology*; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000401:mortality; D016022:Case-Control Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D008133:Long QT Syndrome; D011188:Potassium / Q000097:blood; D055815:Young Adult
chemical_list: D011188:Potassium