中文摘要：

目的研究老年高血压合并糖尿病患者的心率变异性（HRV）及其昼夜变化规律,探讨老年糖尿病患者心脏自主神经变化的临床意义。方法选择87例原发性高血压患者（EH组）及68例高血压合并糖尿病患者（EH＋DM组）,监测24 h动态心电图,进行HRV时域指标SDNN、SDANN、SDNN Index、RMSSD、PNN50的分析。比较2组间HRV指标的差异以及HRV昼夜指标差异。结果 EH＋DM组较EH组24 h、日间、夜间HRV各项指标均明显降低,且有统计学差异;EH组SDNN以及RMSSD呈昼低夜高,但无明显统计学差异,SDNN Index和PNN50仍呈昼低夜高现象（P〈0.01）;EH＋DM组SDNN以及RMSSD呈昼高夜低现象（P〈0.05）,SDNN Index和PNN50昼夜间无统计学差异。结论老年高血压合并糖尿病患者HRV显著降低,高血压患者昼夜节律已有明显受损,高血压合并糖尿病患者昼夜节律进一步受损,心脏自主神经功能失调。

英文摘要：

Objective To analyze heart rate variability（ HRV） and its circadian rhythms in the elderly patients with essential hypertension（ EH） and type 2 diabetes mellitus（ T2DM） and to assess the clinical values of cardiac autonomic neuropathy in the elderly type 2 diabetic patients. Methods HRV parameters,including SDNN,SDANN,SDNNI,RMSSD and PNN50,were obtained from 24 h ambulatory electrocardiogram recording in 87 patients with EH（ EH group）and 68 patients with EH and T2DM（ EH＋DM group）. 24 h HRV,day and night HRV between the two groups were compared. Results HRV parameters were significantly lower in EH＋DM group than those in EH group（ P〈0. 05）,and there were significant differences in SDNN Index and PNN50 between day and night in EH group. Furthermore,SDNN and RMSSD were significantly different between day and night in EH＋DM group. Conclusions HRV in the elderly patients with EH and T2 DM is significantly decreased,which shows that autonomic neuropathy and loss of circadian rhythms exist in the elderly patients with EH and T2 DM.