Abstract
Purpose: Sympathetic nerve activity (SymNA) has been suggested to be increased and contributed to the development of hypertension in obstructive sleep apnea syndrome (OSAS). The purpose is to examine the autonomic nerve activity (ANA) at night and the effects of CPAP titration in OSAS.
Subjects and methods: Thirty-two patients with OSAS and 14 healthy volunteers without sleep disturbance and disordered breathing were recruited. All subjects were examined full polysomnography (PSG) and simultaneously measured ANA at night evaluated by complex demodulation analysis of the heart rate variability using a photoelectric pulse-wave sensor attached to a wrist. Fourteen patients of all were also examined CPAP titration and re-evaluated ANA. SymNA was estimated by LF/HF ratio and parasympathetic nerve activity (ParasymNA) was evaluated by occupancy and durability of high-powered HF.
Results: OSAS showed a significant increased in LF/HF ratio and decreased both the occupancy and durability over 5 min of high-powered HF at night when compared with those in normal subjects. There were significant correlations between LF/HF ratio and AHI (r=0.57) or arousal index (r=0.51). CPAP titration was significantly decreased SymNA and improved parasymNA in OSAS.
Conclusion: These findings suggest that the increased SymNA may contribute to the development of hypertension at night, and CPAP treatment may improved the increased SymNA and decreased blood pressure.
- © 2014 ERS