title: Nocturnal hypoxia and arrhythmias in patients with impaired left ventricular function.
abstract: OBJECTIVE
  To document the incidence of hypoxic episodes in a series of patients with impaired left ventricular function, and to correlate the occurrence of hypoxia with severity of arrhythmia.
  
  
  METHODS
  34 patients with breathlessness and clinical evidence of left ventricular dysfunction.
  
  
  METHODS
  Simultaneous overnight finger oximetry and electrocardiographic monitoring.
  
  
  RESULTS
  High grade arrhythmias (Lown grade > III) occurred in 20/34 (59%) of patients, and frequent dips in oxygen saturation were noticed (mean dip frequency 4.8/h, range 0.1-20.0). 20/34 (59%) of patients had episodic hypoxaemia, including 13/34 (38%) with a classical Cheyne Stokes pattern. There was a correlation between dip frequency and the presence of high grade arrhythmias (those with high grade arrhythmia had mean (SD) 6.7 (5.5) dips/h v 2.2 (3.4) in those without, p < 0.01); there was also a correlation between the presence of arrhythmias and episodic hypoxaemia (episodic hypoxaemia in those with high grade arrhythmias occurred in 17/20 (85%) v 3/14 (21%) of those without arrhythmias, p < 0.002). There was no correlation between the presence of high grade arrhythmias or dip frequency and the extent of left ventricular impairment, which was present in all patients (mean (SD) ejection fraction 26% (13%)).
  
  
  CONCLUSIONS
  Noticeable abnormalities of nocturnal oxygen saturation occur in patients with impaired left ventricular function, and these are associated with high grade arrhythmias. Interventions that limit desaturation may have valuable anti-arrhythmic effects.
authors.affiliation: Department of Cardiology, John Radcliffe Hospital, Headington, Oxford.
authors.forename: T
authors.initials: T
authors.lastname: Cripps
authors.forename: G
authors.initials: G
authors.lastname: Rocker
authors.forename: J
authors.initials: J
authors.lastname: Stradling
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009551:Night Care; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D010100:Oxygen