[The relationship between arousal and nocturnal heart rate variability in patients with obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE To investigate the relationship between arousal and nocturnal heart rate variability (HRV) in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS Twenty-seven patients with moderate to severe OSAHS who underwent overnight polysomnography (PSG) were enrolled, excluding patients with cardiopulmonary and nervous system diseases. An hour continuous PSG monitoring in non-rapid eye movement (NREM) was recorded for all patients. The mean heart rate (HR) in 10 s before each arousal and the peak HR in 10 s after arousal were compared, and the breathing disorder related arousal index (B-ArI) and pulse rate rise index (PRRI) were calculated at this time, and then a correlation analysis was performed. Furthermore, according to minimal oxygen saturation (minSaO(2)), 18 patients with moderate-to-severe OSAHS were matched into 10 events with and without EEG arousal in NREM, and then DeltaHR at apnea termination between these events were compared. RESULTS The peak HR in 10 s after arousal onset [(81.6 +/- 9.4) beats/min] was significantly higher than the mean HR in 10 s before arousal onset [(69.6 +/- 7.3) beats/min, t = -14.87, P < 0.01], and B-ArI was positively correlated to PRRI (r = 0.97, P < 0.01). The DeltaHR of events with EEG arousal at apnea termination [(11.1 +/- 2.8) beats/min] was higher than those without EEG arousal [(7.0 +/- 2.4) beats/min, t = 4.702, P < 0.01]. CONCLUSIONS The results indicate that arousal can influence the function of cardiovascular regulation. Frequent arousal is one of the main causes of the cardiovascular consequences in OSAHS patients.