title: Alteration of cardiac autonomic functions in patients with major depression: a study using heart rate variability measures.
abstract: BACKGROUND
  Depression is associated with greater cardiac morbidity and mortality. One of the contributory factors for this may be altered cardiac autonomic activity in depression. However, cardiac autonomic involvement in depression remains controversial because of methodological issues. In this study, alteration of cardiac autonomic functions was studied in drug-naive patients with major depression without co-morbidity. Heart rate variability, a sensitive measure of neurocardiac autonomic regulation was used in addition to conventional methods of measuring cardiac autonomic functions.
  
  
  METHODS
  We recruited 40 patients suffering from major depression, diagnosed based on DSM-IV-TR criteria. Their cardiac autonomic functions were measured using both conventional and heart rate variability measures. These were compared with those of age- and gender-matched healthy controls.
  
  
  RESULTS
  Patients with major depression showed significantly lesser Valsalva ratio, maximum/minimum ratio and greater sympathovagal balance than healthy controls indicating decreased parasympathetic and increased sympathetic activity.
  
  
  CONCLUSIONS
  Depression is associated with alteration of cardiac autonomic tone towards decreased parasympathetic activity and an increased sympathetic activity. It is possible that a common neurobiological dysfunction contributes to both depression and cardiac autonomic changes in the illness.
authors.affiliation: Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore, Karnataka, 560 029, India.
authors.forename: Kaviraja
authors.initials: K
authors.lastname: Udupa
authors.forename: T N
authors.initials: TN
authors.lastname: Sathyaprabha
authors.forename: Jagadisha
authors.initials: J
authors.lastname: Thirthalli
authors.forename: K R
authors.initials: KR
authors.lastname: Kishore
authors.forename: G S
authors.initials: GS
authors.lastname: Lavekar
authors.forename: T R
authors.initials: TR
authors.lastname: Raju
authors.forename: B N
authors.initials: BN
authors.lastname: Gangadhar
mesh_terms: D000328:Adult; D001342:Autonomic Nervous System Diseases / Q000453:epidemiology* / Q000503:physiopathology*; D003710:Demography; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004562:Electrocardiography; D005260:Female; D006331:Heart Diseases / Q000453:epidemiology* / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D012720:Severity of Illness Index; D014630:Vagus Nerve / Q000503:physiopathology