title: Daytime Cheyne-Stokes respiration in ambulatory patients with severe congestive heart failure is associated with increased mortality.
abstract: BACKGROUND
  Cheyne-Stokes respiration (CSR) frequently occurs in patients with severe heart failure during sleep and may increase mortality. Daytime CSR supposedly poses an even greater risk, but its prevalence and prognostic importance remain elusive. Therefore, we investigated the circadian prevalence of CSR and its influence on survival in patients with heart failure.
  
  
  METHODS
  In 60 consecutive ambulatory patients (mean age+/-SE, 58.0+/-1.5 years; 6 women) with stable severe heart failure (left ventricular ejection fraction, 26+/-1%; New York Heart Association [NYHA] class, 2.6+/-0.1), the breathing pattern was unobtrusively monitored during 24 h of usual activities with a portable respiratory inductive plethysmograph.
  
  
  RESULTS
  During nights, 62% of patients had >or=15 periodic breathing cycles per hour; during days, the corresponding prevalence was 16%. CSR prevailed in 32+/-3% of the night and in 10+/-2% of the day, with peaks at 4:00 am, 2:00 pm, and 6:00 pm. Eighteen patients with CSR during >or=10% of the daytime lived shorter without heart transplantation than 42 patients with <10% of daytime CSR (p<0.05) during 836+/-27 days of follow-up. CSR during >or=10% of the daytime was an independent predictor of mortality (hazard ratio, 3.8; 95% confidence interval, 1.1 to 12.7; p<0.05) when controlling for age, sex, brain natriuretic peptide, left ventricular ejection fraction, and NYHA class.
  
  
  CONCLUSIONS
  CSR occurs in 62% of patients with severe heart failure at night and in 16% during the day. Since daytime CSR is associated with reduced survival, solely performing sleep studies may not allow to adequately assess prognosis and tailor treatment in patients with severe heart failure.
authors.affiliation: Division of Pulmonary Medicine, University Hospital Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Brack
authors.forename: Irene
authors.initials: I
authors.lastname: Thüer
authors.forename: Christian F
authors.initials: CF
authors.lastname: Clarenbach
authors.forename: Oliver
authors.initials: O
authors.lastname: Senn
authors.forename: Georg
authors.initials: G
authors.lastname: Noll
authors.forename: Erich W
authors.initials: EW
authors.lastname: Russi
authors.forename: Konrad E
authors.initials: KE
authors.lastname: Bloch
mesh_terms: D002639:Cheyne-Stokes Respiration / Q000401:mortality* / Q000503:physiopathology*; D002940:Circadian Rhythm; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010991:Plethysmography / Q000295:instrumentation; D011187:Posture; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000401:mortality* / Q000503:physiopathology*