Untreated obstructive sleep apnea was associated with significantly lower respiratory sinus arrhythmia and baroreflex response gains compared to normal controls.
Cross-Sectional (n=17)
Does a closed-loop model analysis of cardiovascular variability reveal differences in autonomic function between normal subjects and patients with untreated obstructive sleep apnea?
Closed-loop model analysis of cardiovascular variability demonstrates impaired autonomic function, specifically blunted baroreflex sensitivity during sleep, in patients with untreated obstructive sleep apnea.
We have developed a model-based approach for estimating the dynamic effects of respiration on heart rate ("RSA") and arterial pressure ("MER"), along with the baroreflex response ("ABR") and the feedforward effect of heart rate on blood pressure ("CID") from a single test procedure. Respiration, heart rate, continuous blood pressure and other polysomnographic variables were monitored in 9 normals and 8 untreated patients with obstructive sleep apnea (OSA). A computer-controlled ventilator was used to vary ventilatory pattern in a randomized breath-to-breath sequence. Using closed-loop model analysis, we estimated the parameters that characterize RSA, ABR, CID and MER. RSA and ABR gains were significantly lower in OSA than normals. During sleep, ABR gain increased threefold in normals but remained unchanged in OSA. CID gain was higher in OSA relative to normals, suggesting increased peripheral vascular resistance. MER gain was also higher in OSA, but only in wakefulness. Apart from increased mean heart rate in OSA, there were no significant differences in other summary and spectral measures of cardiovascular variability. Our approach represents a sensitive, clinically practicable and comprehensive means of assessing autonomic function in OSA during both wakefulness and sleep.
Jo et al. (Thu,) conducted a cross-sectional in Obstructive sleep apnea (n=17). Obstructive sleep apnea vs. Normal controls was evaluated on Cardiovascular variability parameters (RSA, ABR, CID, MER gains). Untreated obstructive sleep apnea was associated with significantly lower respiratory sinus arrhythmia and baroreflex response gains compared to normal controls.