title: Nonlinear analysis of RR interval in euthymic bipolar disorder.
abstract: BACKGROUND
  The bipolar affective disorder is long been speculated to have an autonomic involvement. Nonlinear analysis of heart rate variability has recently been shown to be a reliable noninvasive test for quantitative assessment of the central sympathovagal interaction that modulates cardiovascular autonomic function.
  
  
  METHODS
  We studied 32 euthymic bipolar patients and 24 controls. A high-resolution electrocardiogram was obtained during complete rest. Nonlinear analysis (Poincare plot, largest Lyaponuv exponent, minimal embedding dimension, symbolic dynamic) was used.
  
  
  RESULTS
  There wasn't a statistically significant difference in the nonlinear analysis of the heart rate variability, between the euthymic bipolar patients and controls, in the rest situation.
  
  
  CONCLUSIONS
  The nonlinear analysis of heart rate variability didn't support the notation that there is a disturbance in the autonomic nerves system of bipolar patients in the euthymic state.
authors.affiliation: Ministry of Health Mental Health Center, Faculty of Health Sciences, Psychiatry Research Unit, Ben Gurion University of the Negev, P.O. Box 4600, Beer-Sheva, Israel. dtoder@netvision.net.il
authors.forename: D
authors.initials: D
authors.lastname: Todder
authors.forename: Y
authors.initials: Y
authors.lastname: Bersudsky
authors.forename: H
authors.initials: H
authors.lastname: Cohen
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology*; D016022:Case-Control Studies; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D011569:Psychiatric Status Rating Scales