title: Short-term effects of cardiac resynchronization therapy on sleep-disordered breathing in patients with systolic heart failure.
abstract: OBJECTIVE
  We evaluated the short-term effect of cardiac resynchronization therapy (CRT) on sleep apnea in patients with systolic heart failure.
  
  
  BACKGROUND
  Sleep-disordered breathing is common in patients with left ventricular systolic dysfunction.
  
  
  METHODS
  Twelve patients (mean [+/-SE] age, 59.6+/-7.8 years; mean left ventricular ejection fraction, 28.0+/-2.8%) with an implanted atrial-synchronized biventricular pacemaker for the treatment of left ventricular systolic dysfunction were selected and studied. Each subject underwent polysomnography on 3 consecutive nights with CRT on the first night, CRT off the second night, and CRT on the third night. Echocardiography was performed prior to each polysomnogram.
  
  
  RESULTS
  The central sleep event index (ie, the number of central sleep apneas [CSAs] and hypopneas per hour of sleep) score was lower with CRT compared to that without CRT (mean central sleep event index score with CRT on, 6.9+/-1.7 events per hour of sleep; mean central sleep event index score with CRT off, 14.3+/-2.9 events per hour of sleep; mean central sleep event index score with CRT on, 8.1+/-1.5 events per hour of sleep; p<0.001). Similarly, the cumulative duration of central sleep events (the number of minutes per hour of sleep during CRT) was one half that observed without CRT (CRT on, 2.8+/-0.7 min per hour of sleep; CRT OFF 6.2+/-1.2 min per hour of sleep; CRT ON 3.1+/-0.7 min per hour of sleep; p<0.001). There was a significant correlation between mitral regurgitant volume and central sleep event index on all three nights (r>or=0.77; p<0.01).
  
  
  CONCLUSIONS
  CRT reduces CSA severity in the short term. This reduction correlated significantly with the CRT-mediated reduction of mitral regurgitation.
authors.affiliation: International Clinical Research Center Brno, St. Anne's University Hospital Brno, Pekarska 53, 65691 Brno, Czech Republic. kara.tomas@mayo.edu
authors.forename: Tomas
authors.initials: T
authors.lastname: Kara
authors.forename: Miroslav
authors.initials: M
authors.lastname: Novak
authors.forename: Jiri
authors.initials: J
authors.lastname: Nykodym
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Bybee
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Meluzin
authors.forename: Marek
authors.initials: M
authors.lastname: Orban
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Novakova
authors.forename: Jolana
authors.initials: J
authors.lastname: Lipoldova
authors.forename: David L
authors.initials: DL
authors.lastname: Hayes
authors.forename: Miroslav
authors.initials: M
authors.lastname: Soucek
authors.forename: Jiri
authors.initials: J
authors.lastname: Vitovec
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
mesh_terms: D000368:Aged; D004452:Echocardiography; D005260:Female; D054143:Heart Failure, Systolic / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D017286:Polysomnography; D012720:Severity of Illness Index; D016037:Single-Blind Method; D012891:Sleep Apnea Syndromes / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000628:therapy