title: Hemodynamic profile and heart rate variability in hyperadrenergic versus non-hyperadrenergic postural orthostatic tachycardia syndrome.
abstract: OBJECTIVE
  To investigate differences in hemodynamic profile between hyperadrenergic and non-hyperadrenergic postural orthostatic tachycardia syndrome (POTS) in response to head-up tilt test (HUTT).
  
  
  METHODS
  Ten patients with hyperadrenergic and 33 patients with non-hyperadrenergic POTS underwent HUTT consisting of a 10-min supine phase and 30-min 70° tilted phase. Heart rate (HR), systolic and diastolic blood pressure (dBP), and heart rate variability (HRV) parameters of the two groups were compared.
  
  
  RESULTS
  Hyperadrenergic patients had higher supine HR (82.6 ± 16.3 bpm vs. 73.8 ± 10.4 bpm, p=0.048). Supine HRV analysis showed significantly lower cardiac vagal activity and possible predominance of cardiac sympathetic activity in the hyperadrenergic group. Non-hyperadrenergic patients had lower dBP during the first four minutes of tilt. Furthermore, 60% of non-hyperadrenergic patients had lower average dBP in the 1st minute of tilted phase when compared to supine values, whereas only 2 of 10 hyperadrenergic patients exhibited the same response. Syncope or intolerable symptoms, causing early ending of HUTT, developed earlier in the non-hyperadrenergic group (8.9 ± 6.8 min vs. 21.2 ± 3.5 min, p=0.001).
  
  
  CONCLUSIONS
  Hyperadrenergic and non-hyperadrenergic type of POTS seem to have distinctly different response to HUTT.
  
  
  CONCLUSIONS
  This study has shown significant differences in hemodynamic response to HUTT between hyperadrenergic and non-hyperadrenergic type of POTS indicating possible differences in their pathophysiology.
authors.affiliation: School of Medicine, University of Zagreb, Zagreb, Croatia.
authors.forename: Luka
authors.initials: L
authors.lastname: Crnošija
authors.affiliation: University Hospital Center Zagreb, Department of Neurology, Referral Center for Autonomic Nervous System Disorders, Zagreb, Croatia.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Krbot Skorić
authors.affiliation: University Hospital Center Zagreb, Department of Neurology, Referral Center for Autonomic Nervous System Disorders, Zagreb, Croatia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Adamec
authors.affiliation: University Hospital Centre Zagreb, Department of Laboratory Diagnostics, Zagreb, Croatia.
authors.forename: Mila
authors.initials: M
authors.lastname: Lovrić
authors.affiliation: University Hospital Center Zagreb, Department of Neurology, Referral Center for Autonomic Nervous System Disorders, Zagreb, Croatia.
authors.forename: Anamari
authors.initials: A
authors.lastname: Junaković
authors.affiliation: University Hospital Center Zagreb, Department of Neurology, Referral Center for Autonomic Nervous System Disorders, Zagreb, Croatia.
authors.forename: Antonija
authors.initials: A
authors.lastname: Mišmaš
authors.affiliation: University Hospital Center Zagreb, Department of Neurology, Referral Center for Autonomic Nervous System Disorders, Zagreb, Croatia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Miletić
authors.affiliation: University Hospital Center Zagreb, Department of Neurology, Referral Center for Autonomic Nervous System Disorders, Zagreb, Croatia.
authors.forename: Rujana
authors.initials: R
authors.lastname: Šprljan Alfirev
authors.affiliation: School of Medicine, University of Zagreb, Zagreb, Croatia.
authors.forename: Antun
authors.initials: A
authors.lastname: Pavelić
authors.affiliation: School of Medicine, University of Zagreb, Zagreb, Croatia; University Hospital Center Zagreb, Department of Neurology, Referral Center for Autonomic Nervous System Disorders, Zagreb, Croatia. Electronic address: mhabek@mef.hr.
authors.forename: Mario
authors.initials: M
authors.lastname: Habek
mesh_terms: D000293:Adolescent; D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D054972:Postural Orthostatic Tachycardia Syndrome / Q000175:diagnosis* / Q000503:physiopathology*; D011187:Posture / Q000502:physiology; D018667:Tilt-Table Test / Q000379:methods*; D055815:Young Adult
keywords: Head-up tilt test; Heart rate variability; Hyperadrenergic; Non-hyperadrenergic; Postural orthostatic tachycardia syndrome