title: Long-term continuous positive airway pressure therapy improves cardiac autonomic tone during sleep in patients with obstructive sleep apnea.
abstract: BACKGROUND
  Cardiac autonomic tone after long-term continuous positive airway pressure therapy in patients with obstructive sleep apnea remains unexplored.
  
  
  METHODS
  Thirty patients with obstructive sleep apnea (14 with moderate and 16 with severe obstructive sleep apnea) were studied during a baseline polysomnographic study, after a full night of acute continuous positive airway pressure treatment, and after long-term (~2 years) chronic continuous positive airway pressure therapy. Twenty age- and gender-matched controls with baseline sleep study were selected for comparison purposes. Cross-spectral analysis and the low-frequency (LF) and high-frequency (HF) components of the heart rate variability were computed separately over 10-min ECG epochs during rapid eye movement sleep, non-rapid eye movement sleep, and wakefulness.
  
  
  RESULTS
  During the baseline study, obstructive sleep apnea patients exhibited increased LF, decreased HF, and increased LF/HF ratio during sleep when compared to controls. In a multiple regression model, the mean oxygen saturation explained the increased LF during rapid and non-rapid eye movement sleep in obstructive sleep apnea patients. Acute continuous positive airway pressure therapy decreased the LF modulations and the LF/HF ratio and increased the HF modulations during sleep in patients with severe obstructive sleep apnea. Long-term continuous positive airway pressure therapy decreased LF modulations and LF/HF ratio with increased HF modulations during sleep in patients with moderate and severe obstructive sleep apnea.
  
  
  CONCLUSIONS
  Long-term continuous positive airway pressure reduces the sympathovagal imbalance in patients with moderate and severe obstructive sleep apnea, both during rapid and non-rapid eye movement sleep. Continuous positive airway pressure seems to exert its changes in cardiac autonomic modulation by decreasing the burden of nocturnal hypoxia.
authors.affiliation: Sleep Unit, Clinical Neurophysiology Section, University Clinic of Navarra, Pío XII s/n 31008, Pamplona, Spain. JoseAlberto.PalmaCarazo@nyumc.org.|Department of Neurology, Dysautonomia Center, New York University School of Medicine, 530 First Avenue, Suite 9Q, New York, NY, 10016, USA. JoseAlberto.PalmaCarazo@nyumc.org.
authors.forename: Jose-Alberto
authors.initials: JA
authors.lastname: Palma
authors.affiliation: Sleep Unit, Clinical Neurophysiology Section, University Clinic of Navarra, Pío XII s/n 31008, Pamplona, Spain. jiriarte@unav.es.
authors.forename: Jorge
authors.initials: J
authors.lastname: Iriarte
authors.affiliation: Department of Otolaryngology, University Clinic of Navarra, Pamplona, Spain.
authors.forename: Secundino
authors.initials: S
authors.lastname: Fernandez
authors.affiliation: Sleep Unit, Clinical Neurophysiology Section, University Clinic of Navarra, Pío XII s/n 31008, Pamplona, Spain.|Neurophysiology Laboratory, CIMA, University of Navarra, Pamplona, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Alegre
authors.affiliation: Neurophysiology Laboratory, CIMA, University of Navarra, Pamplona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Valencia
authors.affiliation: Sleep Unit, Clinical Neurophysiology Section, University Clinic of Navarra, Pío XII s/n 31008, Pamplona, Spain.|Neurophysiology Laboratory, CIMA, University of Navarra, Pamplona, Spain.
authors.forename: Julio
authors.initials: J
authors.lastname: Artieda
authors.affiliation: Sleep Unit, Clinical Neurophysiology Section, University Clinic of Navarra, Pío XII s/n 31008, Pamplona, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Urrestarazu
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D045422:Continuous Positive Airway Pressure / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000639:trends; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D012894:Sleep Stages / Q000502:physiology*; D013997:Time Factors; D016896:Treatment Outcome
keywords: CPAP; Heart rate variability; Hypoxia; OSA; Sleep-disordered breathing