Multi-Time Scale Variability Of Autonomic Nervous System Function In Patients With Type 2 Diabetes Mellitus Based On Heart Rate Variability Analysis

The autonomic nervous system(ANS)function of patients with type 2 diabetes mellitus(T2DM)is significantly different from that of healthy people.Through heart rate variability(HRV)analysis,especially non-linear analysis,it can effectively and non-invasively detect the functional damage of ANS in patients with diabetes who have not been detected clinically.However,the measurement time and duration will have an impact on the HRV analysis results.At present,there is a lack of ECG data set to accurately record the HRV measurement time and state information of T2 DM patients.At the same time,long-term data acquisition will inevitably lead to the reform of analysis methods.Can the results of long-term signal analysis provide more information? Can the trend of traditional small time scale represent the trend of large time scale? How to effectively extract the added information in the long-term signal to reflect the long-term change mode? In order to solve the above problems,this paper proposes a multi-time scale HRV analysis algorithm(MTS-HRV)to study the multi-time scale ANS functional state variability in T2 DM patients.Clinical experiments were carried out in the hospital.Combined with the traditional HRV analysis method and the newly proposed multi-time scale HRV analysis method(MTS-HRV),the variability of ANS functional state regulated by blood glucose fluctuation,circadian rhythm and dietary state in T2 DM patients was comprehensively analyzed,and the implementation suggestions for HRV detection in T2 DM patients were put forward.The research work of this paper is mainly composed of the following three parts:a)A new multi-time scale HRV analysis algorithm based on fractal theory,called MST-HRV,was proposed and verified.The results showed that using only a single scale HRV analysis is easy to misunderstand the function of ANS.For example,the relative relationship between the complexity of Ap En in patients with severe heart failure and healthy people is quite opposite in small scale and large scale,and Samp En can not find the complexity difference in large scale.Multi-time scale functional variability of ANS can help to fully understand the physiological differences between the diseased population and healthy people.For example,patients with severe heart failure have less variability with the increase of scale than healthy people,which is consistent with the clinical symptoms of heart failure.The newly proposed MST-HRV analysis algorithm is more inclined to study the internal characteristics of long-term RR interval time series,which reflects the variability of ANS functional state on multiple time scales,and opens up a new perspective for the quantitative evaluation of ANS functional status in T2 DM patients.b)Relationships on HRV and its influencing factors(blood glucose,sleep,eating and time)were studied.The indicators of standard deviation of blood glucose(SDBG)and mean amplitude of glycemic fluctuation(MAGE)in T2 DM patients have a high positive correlation with SDANN(r=0.60,p=0.010)and SD2(r=0.47,p=0.049),which measure the variability of HRV.HRV changes in T2 DM patients can help find low blood glucose levels.When blood glucose levels are too high,the regulatory ability of ANS in T2 DM patients is not enough to provide sufficient HRV response power.HRV index has obvious change rhythm with the change of time and its living state.This rhythm is not only reflected in the circadian rhythm of sleep and non-sleep period(with a large time span),but also in the time fluctuation before,during and after eating(with a small time span).Therefore,for 24-hour ECG signal,only from the overall single scale or short-term HRV analysis will inevitably waste the rhythm information with unique significance contained in the signal,and T2 DM patients may have undergone qualitative changes in this rhythm compared with healthy people.c)The multi-time scale ANS state variability of T2 DM patients was analyzed.It was found that there was a significant decrease in ANS variability in T2 DM at multiple time points or time periods,especially in the four time periods of 2-4 o’clock during night sleep(nocrurnal hypoglycemia at 3 o’clock),6-8 o’clock when waking up at dawn,12-14 o’clock after lunch(T2DM blood glucose rise period)and 19-21 o’clock in the evening(T2DM blood glucose rise period).When the HRV analysis duration of T2 DM patients is 30-90 min,it can comprehensively reflect the benchmark level of ANS function.The analysis of ANS function of T2 DM patients based on HRV should focus on RR-mean,RMSSD,p NN50,SD1/SD2,LF/HF,LFP and Samp En.Based on the results of MTS-HRV analysis,there was a significant correlation between multi period HRV and clinical indexes in T2 DM patients: HRV in T2 DM patients during sleep was correlated with their metabolic level and the degree of autonomic nervous system function injury(especially liver function)(r=0.55,p<0.001);HRV at dawn(6:00-7:00)was significantly correlated with renal function(BUN)in T2 DM patients(r=-0.57,p<0.001);HRV detection after lunch(13:00-14:00)is conducive to the early detection of T2 DM complications(r=-0.45,p=0.005),and can indirectly measure the degree of cardiovascular health(HDL-C and LDL-C)(r=-0.55,p<0.001);The impairment of ANS function in T2 DM patients,especially the metabolic changes affected by sympathetic nerve activity,was related to the HRV index in the evening(19:00-20:00)(r=0.63,p<0.001).