Abstract
Obstructive sleep apnea (OSA) is a respiratory disorder characterized by recurrent airflow obstruction caused by total or partial collapse of the upper airway. It is well known that HRV are diminished in patients with OSA. However, the analysis of different parts of the night and of the evolution within sleep stages in OSA patients has not yet been investigated.
Objectives: Evaluate and compare HRV in 3 intervals of each sleep stage in overnight polysomnographies in OSA and matched healthy controls.
We studied overnight polysomnographies of 6 untreated OSA patients (mean age 50[+-]14 yr, apnea-hypopnea index [AHI]= 9.4 [+-]6 events per/hour) and 6 matched healthy controls. Time and non-linear analysis of R-R intervals (RRi) was performed of the minimum of 3 central 5-minute sample of stage II, III and REM sleep that was free of stage shifts, artifacts, arousals and apneas. Subsequently, we analyzed the average of these stages between OSA and controls.
Results: Comparing the 3 parts of each stage, we did not observed any difference intragroup (P>0.05). In addition, we only observed significant difference of RMSSD index between OSA and controls (P<]0.001) in the first REM stage. In contrast, when compared the average of 3 central 5-minute samples, we observed significant differences of mean RRi, RR tri index, TINN (ms), SD1 and SD2 between OSA and controls (P<0.05) in all stages.
Conclusion: The preliminary results showed that despite of any change in the HRV evolution through 3 intervals of each stage, the number of samples analyzed during the night may influence the results of HRV in overnight polysomnography.
Financial Support: FAPESP.
- © 2012 ERS