title: Circadian pattern of life-threatening ventricular arrhythmia in patients with sleep-disordered breathing and implantable cardioverter-defibrillators.
abstract: BACKGROUND
  Sleep-disordered breathing (SDB) has been associated with various benign cardiac arrhythmias occurring during sleep.
  
  
  OBJECTIVE
  The purpose of this study was to demonstrate that SDB contributes to the development of life-threatening ventricular arrhythmias in patients with an established arrhythmic substrate.
  
  
  METHODS
  We prospectively studied the association between SDB and timing of life-threatening ventricular arrhythmic events in 45 patients with an implantable cardioverter-defibrillator (ICD). SDB was defined as an apnea-hypopnea index (AHI) >10 events/hour based on an overnight sleep study. The primary outcome measure was appropriate ICD therapy, defined as antitachycardia pacing or shock for ventricular tachycardia or ventricular fibrillation during 1-year follow-up.
  
  
  RESULTS
  SDB was present in 26 (57.8%) patients. Appropriate ICD therapies were higher among patients with SDB (73% vs 47%, P = .02). Logistic regression identified SDB as a predictor of any appropriate ICD therapy (odds ratio 4.4, 95% confidence interval 1.4-15.3, P = .01). The risk for ventricular arrhythmias was higher in patients with SDB solely due to an increase in events occurring between midnight and 6 AM (odds ratio 5.6, 95% confidence interval 2.0-15.6, P = .001) with no discernible effect on appropriate ICD therapy during nonsleeping hours (odds ratio 0.7, 95% confidence interval 0.2-2.3, P = .61).
  
  
  CONCLUSIONS
  Patients with an ICD and SDB have a striking increase in the onset of life-threatening ventricular arrhythmic events during sleeping hours. These findings provide a rationale for SDB screening in patients with appropriate ICD therapy if device interrogation reveals a predominance of nocturnal onset of arrhythmias.
authors.affiliation: Department of Cardiology, Rambam Medical Center, Haifa, Israel.
authors.forename: Tawfiq
authors.initials: T
authors.lastname: Zeidan-Shwiri
authors.forename: Doron
authors.initials: D
authors.lastname: Aronson
authors.forename: Khalid
authors.initials: K
authors.lastname: Atalla
authors.forename: Miry
authors.initials: M
authors.lastname: Blich
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Suleiman
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Marai
authors.forename: Lior
authors.initials: L
authors.lastname: Gepstein
authors.forename: Lena
authors.initials: L
authors.lastname: Lavie
authors.forename: Peretz
authors.initials: P
authors.lastname: Lavie
authors.forename: Monther
authors.initials: M
authors.lastname: Boulos
mesh_terms: D000368:Aged; D002940:Circadian Rhythm; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012891:Sleep Apnea Syndromes / Q000150:complications*; D017180:Tachycardia, Ventricular / Q000150:complications* / Q000628:therapy