title: Periodicity of obstructive sleep apnea in patients with and without heart failure.
abstract: OBJECTIVE
  To determine whether the duration of the apnea-hyperpnea cycle is longer in patients with congestive heart failure (CHF) and obstructive sleep apnea (OSA) than in patients with OSA alone, and whether this is related to prolonged circulation time.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Sleep laboratory of a university teaching hospital.
  
  
  METHODS
  Male patients with OSA and CHF (n = 22) or without CHF (n = 18) underwent overnight polysomnography.
  
  
  RESULTS
  Hyperpnea duration, time to peak tidal volume (Vt), and lung-to-ear circulation time (LECT) were measured in all patients. Compared to the non-CHF patients, those with CHF had significantly longer hyperpneas (25.7 +/- 7.8 s vs 17.6 +/- 5.6 s, p < 0.001) and LECT (14.9 +/- 3.4 s vs 9.0 +/- 1.8 s, p < 0.001) [mean +/- SD]. There was also a significant relationship between LECT and hyperpnea duration (r = 0.67, p < 0.001).
  
  
  CONCLUSIONS
  In patients with CHF, prolonged lung-to-chemoreceptor circulation time influences the cycling characteristics of OSA such that it prolongs hyperpnea and sculpts a pattern resembling Cheyne-Stokes respiration. These findings further suggest that the increased tendency to periodic breathing in CHF may predispose to, or alter the physiologic manifestations of OSA.
authors.affiliation: Toronto General Hospital/University Health Network, EC 6-248, 200 Elizabeth St, Toronto, ON, M5G 2C4, Canada.
authors.forename: Clodagh M
authors.initials: CM
authors.lastname: Ryan
authors.forename: T Douglas
authors.initials: TD
authors.lastname: Bradley
mesh_terms: D000328:Adult; D000368:Aged; D001143:Arousal / Q000502:physiology; D001776:Blood Circulation Time; D002628:Chemoreceptor Cells / Q000503:physiopathology; D006333:Heart Failure / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010507:Periodicity; D017286:Polysomnography; D012016:Reference Values; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology; D013990:Tidal Volume / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology
chemical_list: D010100:Oxygen