Continuous positive airway pressure increases heart rate variability in heart failure patients with obstructive sleep apnoea

Clin Sci (Lond). 2008 Feb;114(3):243-9. doi: 10.1042/CS20070172.

Abstract

Patients with heart failure or OSA (obstructive sleep apnoea) have reduced HF-HRV (high-frequency heart rate variability), indicating reduced cardiac vagal modulation, a marker of poor prognosis. CPAP (continuous positive airway pressure) abolishes OSA in patients with heart failure, but effects on daytime HF-HRV have not been determined. We hypothesized that, in patients with heart failure, treatment of coexisting OSA by CPAP would increase morning HF-HRV. In 19 patients with heart failure (left ventricular ejection fraction <45%) and OSA (>/=20 apnoeas and hypopnoeas/h of sleep), HF-HRV was quantified before and 1 month after randomization to a control or CPAP-treated group. In the control group (n=7), there were no changes in HF-HRV over the 1 month study during wakefulness in the morning. In the CPAP-treated group (n=12) HF-HRV increased significantly during wakefulness in the morning [from 2.43+/-0.55 to 2.82+/-0.50 log(ms(2)/Hz); P=0.002] due to an increase in transfer function between changes in lung volume and changes in HF-HRV (92.37+/-96.03 to 219.07+/-177.14 ms/l; P=0.01). In conclusion, treatment of coexisting OSA by nocturnal CPAP in patients with heart failure increases HF-HRV during morning wakefulness, indicating improved vagal modulation of heart rate. This may contribute to improved prognosis.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Anthropometry
  • Aortic Bodies / physiopathology
  • Circadian Rhythm
  • Continuous Positive Airway Pressure*
  • Female
  • Heart Failure / complications
  • Heart Failure / physiopathology*
  • Heart Rate*
  • Humans
  • Male
  • Middle Aged
  • Polysomnography
  • Sleep Apnea, Obstructive / complications
  • Sleep Apnea, Obstructive / physiopathology
  • Sleep Apnea, Obstructive / therapy*