title: Sleep-disordered breathing in patients with symptomatic heart failure: a contemporary study of prevalence in and characteristics of 700 patients.
abstract: OBJECTIVE
  Evaluation of the prevalence and nature of sleep-disordered breathing (SDB) in patients with symptomatic chronic heart failure (CHF) receiving therapy according to current guidelines.
  
  
  RESULTS
  We prospectively screened 700 patients with CHF (NYHA class> or =II, LV-EF< or =40%) for SDB using cardiorespiratory polygraphy (Embletta). Furthermore, echocardiography, cardiopulmonary exercise and 6-min walk testing were performed. Medication included ACE-inhibitors and/or AT1-receptor blockers in at least 94%, diuretics in 87%, beta-blockers in 85%, digitalis in 61% and spironolactone in 62% of patients. SDB was present in 76% of patients (40% central (CSA), 36% obstructive sleep apnoea (OSA)). CSA patients were more symptomatic (NYHA class 2.9+/-0.5 vs. no SDB 2.57+/-0.5 or OSA 2.57+/-0.5; p<0.05) and had a lower LV-EF (27.4+/-6.6% vs. 29.3+/-2.6%, p<0.05) than OSA patients. Oxygen uptake (VO(2)) was lowest in CSA patients: predicted peak VO(2) 57+/-16% vs. 64+/-18% in OSA and 63+/-17% in no SDB, p<0.05. 6-min walking distances were 331+/-111 m in CSA, 373+/-108 m in OSA and 377+/-118 m in no SDB (p<0.05).
  
  
  CONCLUSIONS
  This study confirms the high prevalence of SDB, particularly CSA in CHF patients. CSA seems to be a marker of heart failure severity.
authors.affiliation: Department of Cardiology, Heart and Diabetes Center North Rhine-Westphalia, Bad Oeynhausen, Germany. ooldenburg@hdz-nrw.de <ooldenburg@hdz-nrw.de>
authors.forename: Olaf
authors.initials: O
authors.lastname: Oldenburg
authors.forename: Barbara
authors.initials: B
authors.lastname: Lamp
authors.forename: Lothar
authors.initials: L
authors.lastname: Faber
authors.forename: Helmut
authors.initials: H
authors.lastname: Teschler
authors.forename: Dieter
authors.initials: D
authors.lastname: Horstkotte
authors.forename: Volker
authors.initials: V
authors.lastname: Töpfer
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020182:Sleep Apnea, Central / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D013147:Spirometry / Q000379:methods; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging; D016138:Walking