A sleep-related breathing disorder, common in heart failure, increases one's heart rate variability.
Further, central sleep apnea (CSA) and obstructive sleep apnea (OSA) produce different patterns of heart rate variability, which are likely to reflect the different pathophysiological mechanisms involved, according to a study published in the November 1 issue of the journal SLEEP.
Matthew T. Naughton, MD, of Alfred Hospital and Monash University in Melbourne, Australia, evaluated 21 patients with heart failure who were referred for polysomnography for investigation of a sleep-related breathing disorder. For each subject, two conditions were examined: a sleep-related breathing disorder and stable breathing.
There were three main findings of this study:
- Within the subjects, the transition from stable breathing to a sleep-related breathing disorder was associated with an increase in heart rate variability, as well as an increase in the low frequency/high frequency ratio.
- No difference in heart rate variability was found from samples taken from the beginning and end of the sleep period and, importantly, no evidence that cardiac autonomic regulation altered during the night independent of a sleep-related breathing disorder.
- OSA and CSA produced different patterns of heart rate variability, with OSA showing increased absolute high frequency power and reduced very low frequency percentage compared with CSA.
"Heart rate patterns are influenced enormously by breathing patterns,” said Dr. Naughton. “In heart failure patients during sleep, this information might be able to determine the presence or absence and type of sleep apnea. This could be useful in determining the stability of heart failure (and therefore predict a decline in heart function and signal when additional anti-heart failure therapies are required) and also signal when alternative therapies may be required (such as those directed towards treating OSA). Further work is required in this field."