title: Differing effects of obstructive and central sleep apneas on stroke volume in patients with heart failure.
abstract: BACKGROUND
  Obstructive sleep apnea and central sleep apnea increase risk of mortality in patients with heart failure (HF), possibly because of hemodynamic compromise during sleep. However, beat-to-beat stroke volume (SV) has not been assessed in response to obstructive and central events during sleep in patients with HF. Because obstructive events generate negative intrathoracic pressure that reduces left ventricular (LV) preload and increases afterload, but central events do not, obstructive events should lead to greater hemodynamic compromise than central events.
  
  
  OBJECTIVE
  To determine the effects of obstructive and central apneas and hypopneas during sleep on SV in patients with HF.
  
  
  METHODS
  Patients with systolic HF (LV ejection fraction ≤ 45%) and sleep apnea underwent beat-to-beat measurement of SV by digital photoplethysmography during polysomnography. Change in SV from before to the end of obstructive and central respiratory events was calculated and compared between these types of events.
  
  
  RESULTS
  Changes in SV were assessed during 252 obstructive and 148 central respiratory events in 40 patients with HF. Whereas SV decreased by 6.8 (±8.7)% during obstructive events, it increased by 2.6 (±5.4)% during central events (P < 0.001 for difference). For obstructive events, reduction in SV was associated independently with LV ejection fraction, duration of respiratory events, and degree of oxygen desaturation.
  
  
  CONCLUSIONS
  In patients with HF, obstructive and central respiratory events have opposite hemodynamic effects: whereas obstructive sleep apnea appears to have an adverse effect on SV, central sleep apnea appears to have little or slightly positive effects on SV. These observations may have implications for therapeutic approaches to these two breathing disturbances.
authors.affiliation: Sleep Research Laboratory, Centre for Sleep Health and Research, and Department of Medicine, University Health Network Toronto Rehabilitation Institute and Toronto General Hospital, Toronto, Ontario, Canada.
authors.forename: Dai
authors.initials: D
authors.lastname: Yumino
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kasai
authors.forename: Derek
authors.initials: D
authors.lastname: Kimmerly
authors.forename: Vinoban
authors.initials: V
authors.lastname: Amirthalingam
authors.forename: John S
authors.initials: JS
authors.lastname: Floras
authors.forename: T Douglas
authors.initials: TD
authors.lastname: Bradley
mesh_terms: D000328:Adult; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods; D020182:Sleep Apnea, Central / Q000150:complications / Q000503:physiopathology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D013318:Stroke Volume; D016277:Ventricular Function, Left