title: Characterisation of sleep disturbances in postural orthostatic tachycardia syndrome: a polysomnography-based study.
abstract: OBJECTIVE
  Postural orthostatic tachycardia syndrome (PoTS) has been frequently associated with sleep disturbances but objective sleep data are lacking. In addition, although regional autonomic denervation has been described, less is known about autonomic nervous activity overnight in these patients.
  
  
  METHODS
  A full polysomnography and heart rate variability were performed on 37 patients diagnosed with PoTS . In addition, a multiple sleep latency test (MSLT) was conducted on a subgroup of patients with excessive daytime sleepiness.
  
  
  RESULTS
  The polysomnographic data did not show major pathological findings except the percentage spent in rapid eye movement (REM) sleep which was slightly reduced at 18.4%. The MSLT did not confirm excessive daytime sleepiness as median mean sleep latency was 14.4 min (11.8-17.5). When comparing patients with and without subjective daytime sleepiness, it was found that the latter had a reduced parasympathetic activation at night as expressed by the average high frequency [6936.5 ms(2) (6028.2-8675.5) vs. 4689.5 (3922.7-7685.2) p < 0.05].
  
  
  CONCLUSIONS
  Patients with PoTS do not exhibit polysomnographic findings consistent with relevant sleep pathologies nor objective daytime sleepiness. Subjective daytime sleepiness is associated with enhanced activation of the parasympathetic nervous system.
authors.affiliation: Guy's and St. Thomas' NHS Foundation Trust, Sleep Disorders Centre, London, UK; Department of Medicine (DIMED), University of Padua, Padua, Italy. Electronic address: martino.pengo@gstt.nhs.uk.
authors.forename: M F
authors.initials: MF
authors.lastname: Pengo
authors.affiliation: Guy's and St. Thomas' NHS Foundation Trust, Sleep Disorders Centre, London, UK.
authors.forename: S
authors.initials: S
authors.lastname: Higgins
authors.affiliation: Guy's and St. Thomas' NHS Foundation Trust, Sleep Disorders Centre, London, UK.
authors.forename: P
authors.initials: P
authors.lastname: Drakatos
authors.affiliation: Department of Cardiology, King's College London Hospital, Denmark Hill, London, UK.
authors.forename: K
authors.initials: K
authors.lastname: Martin
authors.affiliation: Department of Cardiology, King's College London Hospital, Denmark Hill, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Gall
authors.affiliation: Department of Medicine (DIMED), University of Padua, Padua, Italy.
authors.forename: G P
authors.initials: GP
authors.lastname: Rossi
authors.affiliation: Guy's and St. Thomas' NHS Foundation Trust, Sleep Disorders Centre, London, UK; Department of Clinical Neuroscience, Institute of Psychiatry, King's College London, London, UK.
authors.forename: G
authors.initials: G
authors.lastname: Leschziner
mesh_terms: D000328:Adult; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D017286:Polysomnography; D054972:Postural Orthostatic Tachycardia Syndrome / Q000150:complications / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000209:etiology / Q000503:physiopathology*
keywords: Autonomic nervous system; Heart rate; Heart rate variability; PoTS; Sleep latency