title: Variation in severity and type of sleep-disordered breathing throughout 4 nights in patients with heart failure.
abstract: BACKGROUND
  Over 50% of patients with chronic heart failure (CHF) have sleep-disordered breathing (SDB). Any variation in the type of SDB in CHF will have implications for patient management. Currently there is good evidence for treatment of obstructive sleep apnea (OSA) in CHF with continuous positive airway pressure; however, for central sleep apnea (CSA) the treatment is less clear.
  
  
  OBJECTIVE
  The aim of this study was to investigate the variation in the severity and type of SDB (OSA vs. CSA) throughout 4 consecutive nights in CHF patients with SDB.
  
  
  METHODS
  Nineteen male CHF patients (mean+/-sd: age 61+/-9 years; left ventricular ejection fraction: 34+/-10% and percent predicted peak VO2: 67+/-19%) underwent cardiorespiratory monitoring in their own home throughout 4 consecutive nights.
  
  
  RESULTS
  There was minimal variation in apnea-hypopnea index (AHI) throughout 4 nights in CHF patients with SDB [intraclass correlation coefficient (95% confidence interval (CI)): 0.97 (95% CI 0.76 and 0.97)]. Eight patients [42% (95% CI 20% and 64%)] demonstrated a shift in the type of their SDB, from CSA to OSA or vice versa; these patients had significantly smaller neck circumference (group mean+/-sd) 42+/-2 vs. 44+/-2 cm; p=0.04), and had significant variation in the central AHI [intraclass correlation coefficient: 0.51 (95% CI 0.16 and 0.85)].
  
  
  CONCLUSIONS
  A single night of cardiorespiratory monitoring is representative of moderate-to-severe SDB in patients with CHF. However, a high proportion of patients shift their type of SDB over 4 nights. These findings may have implications for the management of SDB in CHF.
authors.affiliation: Clinical and Academic Unit of Sleep & Breathing, National Heart & Lung Institute, Royal Brompton Hospital, Imperial College, Sydney Street, London SW3 6NP, UK. ali.vazir@btinternet.com <ali.vazir@btinternet.com>
authors.forename: Ali
authors.initials: A
authors.lastname: Vazir
authors.forename: Peter C
authors.initials: PC
authors.lastname: Hastings
authors.forename: Ioannis
authors.initials: I
authors.lastname: Papaioannou
authors.forename: Philip A
authors.initials: PA
authors.lastname: Poole-Wilson
authors.forename: Martin R
authors.initials: MR
authors.lastname: Cowie
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Morrell
authors.forename: Anita K
authors.initials: AK
authors.lastname: Simonds
mesh_terms: D000368:Aged; D002110:Caffeine / Q000008:administration & dosage; D002940:Circadian Rhythm; D000431:Ethanol / Q000008:administration & dosage; D006333:Heart Failure / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000379:methods; D018579:Patient Selection; D017286:Polysomnography; D011187:Posture; D011446:Prospective Studies; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000209:etiology*; D020182:Sleep Apnea, Central / Q000209:etiology; D020181:Sleep Apnea, Obstructive / Q000209:etiology
chemical_list: D002110:Caffeine; D000431:Ethanol