title: Avoidance of the left lateral decubitus position during sleep in patients with heart failure: relationship to cardiac size and function.
abstract: OBJECTIVE
  We sought to determine whether patients with congestive heart failure (CHF) avoid the left lateral decubitus (LLD) position during sleep and, if so, whether this avoidance would be more pronounced in those with greater degrees of cardiomegaly.
  
  
  BACKGROUND
  Anecdotal reports suggest that, in patients with CHF, the LLD position is associated with discomfort due to the enlarged apical heart beat and greater degree of dyspnea (trepopnea) than other positions. It has also been suggested that the LLD position is associated with increased sympathetic nervous activity.
  
  
  METHODS
  A total of 75 patients with CHF and 75 control subjects underwent nocturnal polysomnography with monitoring of body position. Echocardiography was performed in all patients with CHF to determine left ventricular end-diastolic diameter (LVEDD). A total of 40 patients underwent cardiac catheterization from which pulmonary capillary wedge pressure (PCWP) and cardiac output (CO) were obtained.
  
  
  RESULTS
  Patients with CHF spent significantly less time in the LLD position than in the right lateral decubitus position. No such difference was observed among control subjects. Among patients with CHF, those with larger LVEDD, higher PCWP, and lower CO spent less time in the LLD position.
  
  
  CONCLUSIONS
  Patients with CHF avoid the LLD position spontaneously during sleep. This may be a protective strategy to avoid discomfort from the enlarged apical heart beat or further hemodynamic or autonomic compromise.
authors.affiliation: Sleep Research Laboratory of the Toronto Rehabilitation Institute, Ontario, Canada.
authors.forename: Richard S T
authors.initials: RS
authors.lastname: Leung
authors.forename: Michael E
authors.initials: ME
authors.lastname: Bowman
authors.forename: John D
authors.initials: JD
authors.lastname: Parker
authors.forename: Gary E
authors.initials: GE
authors.lastname: Newton
authors.forename: T Douglas
authors.initials: TD
authors.lastname: Bradley
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology; D015992:Body Mass Index; D006328:Cardiac Catheterization; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture; D011669:Pulmonary Wedge Pressure / Q000502:physiology; D012890:Sleep; D016277:Ventricular Function, Left / Q000502:physiology