Increased QT variability in patients with anorexia nervosa--an indicator for increased cardiac mortality?
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.
Koschke
Mandy
M
Department of Psychiatry and Psychotherapy, University Hospital, Jena, Germany.
Boettger
Michael K
MK
Macholdt
Claudia
C
Schulz
Steffen
S
Yeragani
Vikram K
VK
Voss
Andreas
A
Bär
Karl-Jürgen
KJ
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
D011188:Potassium