title: Sleep-disordered breathing increases risk for fatal ventricular arrhythmias in patients with chronic heart failure.
abstract: BACKGROUND
  It has been shown that sleep-disordered breathing (SDB) is associated with adverse prognosis in patients with chronic heart failure (CHF), but little is known about the relationship between SDB and life-threatening arrhythmias.
  
  
  RESULTS
  Fifty patients with CHF and SDB (33 male; mean age, 61 years) underwent Holter electrocardiogram and portable sleep monitoring simultaneously. The circadian variation in positive T-wave alternans (TWA; >65 μV) was determined during 6-h intervals (0-6, 6-12, 12-18, and 18-24 h). In addition, power spectral analysis of heart rate variability (HRV) was evaluated across a 24-h period. The subjects were divided into 2 groups based on whether respiratory disturbance index was ≥20 events/h (Group A, n=24) or not (Group B, n=26). The prevalence of positive TWA, parameters in HRV and the occurrence of ventricular tachycardia (>5 beats) were compared between the 2 groups. The prevalence of positive TWA in Group A was significantly higher than that in Group B in all 6-h intervals. Low-frequency and high-frequency powers of HRV were significantly lower in Group A than in Group B across a 24-h period. Importantly, the prevalence of ventricular tachycardia was significantly higher in Group A than in Group B (46% vs. 19%, P=0.04).
  
  
  CONCLUSIONS
  SDB may induce cardiac electrical instability associated with life-threatening arrhythmias across a 24-h period in CHF.
authors: Department of Cardiology and Hematology, Fukushima Medical University, Hikarigaoka, Fukushima 960-1295, Japan. smyamada@fmu.ac.jp
authors: Shinya
authors: S
authors: Yamada
authors: Hitoshi
authors: H
authors: Suzuki
authors: Masashi
authors: M
authors: Kamioka
authors: Satoshi
authors: S
authors: Suzuki
authors: Yoshiyuki
authors: Y
authors: Kamiyama
authors: Akiomi
authors: A
authors: Yoshihisa
authors: Shu-ichi
authors: S
authors: Saitoh
authors: Yasuchika
authors: Y
authors: Takeishi
mesh_terms: D000368:Aged; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D017180:Tachycardia, Ventricular / Q000209:etiology / Q000401:mortality / Q000503:physiopathology*; D013997:Time Factors