Objective: To study the effect of obstructive sleep apnea-hypopnea syndrome(OSAHS) on cardiac arrhythmias and heart rate variability(HRV) in patients with hypertension.Methods: A total of 67 patients with hypertension and OSAHS(Group HT+O) and 42 patients with hypertension but no OSAHS(Group HT)and 41 healthy person(Group N) were enrolled.All subjects in 3 groups underwent ambulatory electrocardiogram

The rate of cardiac arrhythmias

each index of frequency spectrum and time domain of heart rate variability were analyzed.Results: Prevalence rates of cardiac arrhythmia was markedly higher in Group HT+O(37.34%)than that in Group HT(16.7%)

(P<0.05).Prevalence rates of frequent atrial premature beats

atrial tachycardia

>2 s sinus arrest

Ⅱ°Ⅰ and Ⅱ°Ⅱ atrial ventricular block were 22.3%、31.3%、16.4%、14.9% and 10.4% respectively in Group HT+O

while in Group HT those were 7.1%、9.5%、2.3%、2.3% and 0 respectively(P<0.05).LF

HF

SDNN

SDANN and rMSSD were lower in Group HT+O than those in Group HT

but only SDNN and SDANN had the significant difference.those of Group HT+O were111.19±33.95 and 96.64±37.34

while those of Group H were 131.95±37.5 and 122.48±42.36(P<0.05).L/H was significantly higher in Group HT+O(2.02±0.58)than that in Group N(1.49±0.40)(P<0.05)

L/H in Group HT was 1.87±0.61.Conclusion: OSAHS has been shown to have significantly deteriorative effect on cardiac arrhythmias and HRV.The function of autonomic nerve and balance between sympathetic nerve and vagus nerve in patients with hypertension with OSAHS were more deteriorated than patients with hypertension but no OSAHS.