The analysis of heart rate variability(HRV) in 21 patients with severe obstructive sleep apnea syndrome(OSAS).

Objectives:To study HRV in patients with severe obstructive sleep apnea syndrome,find out the nocturnal variation of autonomic nervous system in OSA patients.Methods:7-hours nocturnal polysomnography and analysis of HRV were recorded in 21 patients with severe OSA and 20 controls.Results: In severe OSAS patients:AHI,the lowest oxygen desaturations(Sao 2),average Sao 2 were lower than controls,the percent of SaO 2 lower than 90% was higher than controls;SDNN,CV were higher,LF/HF was lower Positive correlation was detected between the percent of SaO 2 lower than 90% and LF/HF.Conclusion:The results suggested that the activities of sympathetic nervous and vagus nervous were enhanced in severe OSAS patients,the enhance of sympathetic nervous activity was obviously.Positive correlation between the time of hypoxaemia persistent and the activity of sympathetic nerve.