Elderly hypertension patients with obstructive sleep apnea syndrome and heart rate and blood pressure variability and the intervention effects of home-based continuous positive airway pressure therapy

Abstract

Objective To study the correlation of the degree of sleep apnea with arrhythmia, heart rate variability(HRV)and blood pressure variability(BPV)in elderly patients with obstructive sleep apnea hypopnea syndrome(OSAHS), and to investigate the intervention effects of home-based continuous positive airway pressure(CPAP)treatment. Methods A total of 122 elderly hypertension patients with OSAHS were recruited in the prospective study.Patients were divided into three groups according to the sleep apnea hypopnea index(apnea hypopnea index, AHI): the mild OSAHS group(5 times/h≤AHI≤15 times/h, n=42), moderate OSAHS group(15 times/h 30 times/h, n=40). All patients took ambulatory electrocardiogram and ambulatory blood pressure examinations before and after three months of CPAP treatment.The incidences of arrhythmia, HRV and BPV indexes of each group before and after CPAP treatment were compared between the groups. Results The incidences of premature atrial contraction, atrial tachycardia and premature ventricular beats were higher in the moderate and severe OSAHS groups than in the mild OSAHS group(P<0.01). Compared with the mild OSAHS group, the RR interval standard deviation(SDNN), root mean square of successive differences(rMSSD), proportion of patients with consecutive RR-interval differences greater than 50 ms(PNN5), standard deviation of the averaged normal RR intervals for all 5 min segments and deceleration capacity of rate increased in the moderate and severe OSAHS groups(P<0.05), and the increases were more obvious in the severe group.Compared with the mild OSAHS group, the standard deviation of 24-h systolic blood pressure, standard deviation of 24-h diastolic blood pressure, standard deviation of daytime systolic blood pressure, standard deviation of nighttime systolic blood pressure and incidence of non-dipper hypertension increased in the moderate and severe OSAHS groups(P<0.05), with the increases were more obvious in the severe group, and the differences was significant between the moderate and severe OSAHS groups(P<0.05). HRV and BPV indicators improved except for high frequency(HF)/low frequency(LF)in all groups(P<0.05)after home treatment of CPAP, and the improvement was more obvious in the severe group.The incidence of non-dipper circadian rhythm of blood pressure improved more significantly in the severe OSAHS group than in the moderate OSAHS group. Conclusions With aggravated sleep apnea, the incidences of arrhythmias such as premature atrial contraction, atrial tachycardia, and premature ventricular contraction are increased and the HRV and BPV are enlarged in elderly hypertension patients complicated with OSAHS.The home treatment of CPAP can improve the above indicators, and it is an effective way to treat OSAHS complicated by hypertension in elderly patients. Key words: Hypertension; Sleep apnea, obstructive; Intermittent pressure ventilation