title: Relationship between beta-blocker treatment and the severity of central sleep apnea in chronic heart failure.
abstract: BACKGROUND
  We sought to examine the relationship between use of beta-blockers and the severity of central sleep apnea (CSA) in patients with chronic heart failure.
  
  
  METHODS
  We performed polysomnography in 45 patients with chronic heart failure (New York Heart Association functional class II/III and left ventricular ejection fraction < 50%) and examined the relationship between use of beta-blockers and the severity of CSA. Central apnea index (CAI) was used as an indicator of CSA.
  
  
  RESULTS
  Patients receiving beta-blockers (ie, carvedilol; n = 27) had lower apnea-hypopnea index (AHI) and CAI than patients not receiving beta-blockers (n = 18) [mean +/- SD, 14 +/- 11 vs 33 +/- 17, p < 0.0001; and 1.9 +/- 3.2 vs 11 +/- 12, p = 0.0004, respectively]. AHI and CAI were negatively correlated with the dose of carvedilol (Spearman rho = - 0.61, p < 0.0001; and Spearman rho = - 0.57, p = 0.0002, respectively). Multiple regression analysis selected no use of beta-blockers as an independent factor of CAI (p = 0.0006). In five patients with CAI > 5 who underwent serial sleep studies, CAI decreased significantly after 6 months of treatment with carvedilol (9.5 +/- 4.9 to 1.3 +/- 2.4, p = 0.03).
  
  
  CONCLUSIONS
  In patients with chronic heart failure, CAI was lower according to the dose of beta-blockers, and no use of beta-blockers was independently associated with CAI. In addition, 6 months of treatment with carvedilol decreased CAI. These results suggest that beta-blocker therapy may dose-dependently suppress CSA in patients with chronic heart failure.
authors.affiliation: Second Department of Internal Medicine, Faculty of Medicine, Oita University, Hasama, Yufu, Oita 879-5593, Japan. akira@med.oita-u.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Tamura
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kawano
authors.forename: Shigeru
authors.initials: S
authors.lastname: Naono
authors.forename: Munenori
authors.initials: M
authors.lastname: Kotoku
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Kadota
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D002227:Carbazoles / Q000009:adverse effects* / Q000627:therapeutic use; D000077261:Carvedilol; D016009:Chi-Square Distribution; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011412:Propanolamines / Q000009:adverse effects* / Q000627:therapeutic use; D020182:Sleep Apnea, Central / Q000175:diagnosis / Q000209:etiology*; D018709:Statistics, Nonparametric
chemical_list: D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol