2型糖尿病患者无症状心肌缺血心率变异性的研究

The study of heart rate variability in type 2 diabetic patients with silent myocardial iscbemia

目的冠心病是2型糖尿病主要心血管并发症，且经常表现为无症状心肌缺血（SMI），本研究观察2型糖尿病患者SMI发作与心率变异性的相关性。方法在我院行运动负荷心肌灌注显像检查的患者中，选取1个月内做过动态心电图监测的157名无冠心病临床症状的2型糖尿病患者，其中34例为SMI患者；123例为无心肌缺血发作患者，并在其中随机选37例为对照组。结果SMI的发生率为21．6％；SMI组除24小时平均心率高于无心肌缺血组外。心率变异性各参数中：总体标准差、均值标准差、标准差均值、差值的均方根和差值〉50ms的百分比与无心肌缺血组相比较均明显下降。结论心率变异性减低与2型糖尿病合并SMI明显相关，而心率变异性减低作为评价心脏神经自主病变的早期信号，说明2型糖尿病合并SMI的发病与心脏自主神经病变密切相关，心率变异性或可作为无症状的2型糖尿病患者SMI筛查的指标之一。

Objective Coronary heart disease is the major complication in patients with type 2 diabetes mellitus（ T2DM）, is often asymptomatic. The aim of the study is to determine the relationship between heart rate variability（HRV） and the pathogenesis of silent myocardial ischemia（SMI） in T2DM. Methods Data of 157 asymptomatic diabetic patients were retrospectively analyzed. All the patients were detected by stress myocardial perfusion imaging with ^99Tcm-MIBI. The prevalence of ischemia was assessed by myocardial perfusion imaging. A total of 34 patients were found to have SMI. 123 patients were detected as without myocardial ischemia. From this pool,37 patients were randomly chosen as control group. All the selected patients were also underwent ambulatory ECG in a month, the mean heart rate （HR） and the measure of HRV indices from ambulatory ECG recordings as a sign of cardiovascular autonomic neuropathy （CAN） were used for analyzing variability. Results A total of 34 patients （ 21.6% ） were found to have SMI. HRV parameters such as SDNN, SDANN, SDNNI, RMSSD, PNN50 were decreased in SMI group. Mean HR was higher in SMI than in control group. Conclusions Our results demonstrated that the significant relationship between SMI and the disturbed HRV. Abnormal HRV was early signal for CAN. We speculated CAN was closely correlated with SMI in patients with T2DM. So HRV might be a proper screening tool for risk stratification of SMI in asymptomatic diabetic patients.