title: Heart rate and blood pressure changes during autonomic nervous system challenge in panic disorder patients.
abstract: OBJECTIVE
  To test the hypothesis that panic disorder (PD) patients have a heightened or deregulated autonomic nervous system at rest and during autonomic challenge compared with healthy controls (HC); and to test a second hypothesis that severity of illness differentiates patients'; sympathovagal balance both at rest and during orthostatic challenge.
  
  
  METHODS
  Spectral analysis of heart rate (HR) and blood pressure was performed on 30 PD and 10 HC participants during an orthostatic challenge (head-up tilt).
  
  
  RESULTS
  PD patients presented higher HR (p < .001), lower heart rate variability (HRV) (p < .015), higher mean diastolic blood pressure (p < .006), higher low-frequency component of HR (p < .001), and a higher ratio of low-frequency to high-frequency component of HR (LF/HF) (p < .022) than HC at baseline. During tilt, PD patients responded with higher HR (p < .039), lower HRV (p < .043), increased mean diastolic blood pressure (p < .028), and a mild increase in LF/HF, whereas controls responded with a five-fold increase in LF/HF (p < .022). Patients with higher illness severity ratings (Clinical Global Impression Scale) showed higher HR (p < .002), lower HRV (p < .026), and a lower total power of systolic blood pressure (p < .02) compared with less ill patients.
  
  
  CONCLUSIONS
  These findings demonstrate a consistently higher or deregulated autonomic arousal in PD patients at rest and during orthostatic challenge compared with HC. These data also reveal a possible association between the level of anxiety illness severity and sympathovagal balance, which may imply greater cardiac risk.
authors.affiliation: Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA. jose.martinez@mssm.edu
authors.forename: Jose M
authors.initials: JM
authors.lastname: Martinez
authors.forename: Amir
authors.initials: A
authors.lastname: Garakani
authors.forename: Horacio
authors.initials: H
authors.lastname: Kaufmann
authors.forename: Cindy J
authors.initials: CJ
authors.lastname: Aaronson
authors.forename: Jack M
authors.initials: JM
authors.lastname: Gorman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000379:Agoraphobia / Q000175:diagnosis / Q000503:physiopathology; D001143:Arousal / Q000502:physiology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016584:Panic Disorder / Q000175:diagnosis* / Q000503:physiopathology*; D010555:Personality Inventory; D012720:Severity of Illness Index; D013564:Sympathetic Nervous System / Q000503:physiopathology; D018667:Tilt-Table Test / Q000379:methods / Q000706:statistics & numerical data*; D014630:Vagus Nerve / Q000503:physiopathology