The Relationship Between Heart Rate Variability And Physical Function In The Elderly

Objective:To analyze the relationship between the indicators of heart rate variability(HRV)in 24h dynamic electrocardiogram and physical function in the elderly and the predictive value of heart rate variability indicators to physical function,in order to clarify the influence of autonomic nervous function on the physical function in the elderly and screen the HRV indicators with predictive value for the physical function in the elderly;to analyze the correlation between HRV and heart structure and function,and to explore the effect of autonomic nervous function on heart structure and function.Methods:A total of 157 patients,including 69 males and 88 females with an average age of 76.86±7.14 years,were enrolled in the department of geriatric medicine of Dalian Friendship Hospital from October 2017 to December 2018 who met the inclusion criteria,namely the age of patients was more than 65 years old and their gender was not limited.The following data were collected for all enrolled patients(1)general data:including name,gender,age,height,weight,body mass index,whether take any medications,whether have essential hypertension,coronary heart disease,cerebral palsy and type 2diabetes mellitus.(2)Laboratory data:fasting venous blood glucose(FBG),triglyceride(TG),total cholesterol(TC),high-density lipoprotein cholesterol(HDL-C),low-density lipoprotein cholesterol(LDL-C),glutamic-pyruvic transaminase(ALT),glutamic oxalacetic transaminase(AST),urea nitrogen(BUN),creatinine(CRE).(3)Heart structural and functional indicators:left atrial diameter(LA),left ventricular end diastolic diameter(LVEDD),left ventricular ejection fraction(LVEF);(4)the indicators of heart rate variability(HRV)in 24h dynamic electrocardiogram include:standard deviation of normal to normal sinus R-R intervals within 24 hours(SDNN,ms),standard deviation of the mean value of the 5-minute sinus R-R interval(SDANN,ms),the mean of the standard deviation of the 5 minutes sinus R-R interval(SDNN index,ms),the root mean square of the difference between the normal adjacent cardiac cycles(rMSSD,ms),the percentage of the difference between the two adjacent normal cardiac cycles greater than50ms(PNN50,unit%),the ratio of the total number of sinus interbeats to the histogram height of sinus interbeats(triangular index),total power(TP,ms~2/Hz),Ultra low frequency power(ULF,ms~2/Hz),very low frequency power(VLF,ms~2/Hz),low frequency power(LF,ms~2/Hz),high frequency power(HF,ms~2/Hz),low frequency/high frequency(LF/HF);(5)Physical function evaluation indicators:Activities of daily living(ADL)score,instrumental activities of daily living scale(IADL),pace measurement and handgrip strength.Grouping according to the score and measurement results of physical function:(a)According to the Activities of daily living(ADL)score,the patients were divided into self-care group,semi-self-care group and non-self-care group;(b)The patients were divided into normal group,mild dependence group,moderate dependence group and severe dependence group according to the IADL score;(c)The patients were divided into normal group and slow group according to the stepping speed measurements.(d)According to the handgrip measurement value,the patients was divided into the male normal group and the male descending group,the female normal group and the female descending group.The difference of heart rate variability indicators in different physical function states and its correlation with heart rate variability,the predictive value of HRV to body function and the correlation between HRV and heart structure and function were analyzed.Result:1.There were no differences in gender composition,height,weight,body mass index,FBG,TC,TG,LDL-C,HDL-C,ALT,AST,CRE and BUN among different physical function grade groups(P>0.05),but there were only differences in age,the age of the semi-self-care group and the non-self-care group was higher than that of the self-care group(P<0.05),but there was no difference in age between the semi-self-care group and the non-self-care group(P>0.05).The age of moderate dependence group and severe dependence group was higher than that of normal group and mild dependence group(P<0.05),but there was no difference among mild dependence group,moderate dependence group and severe dependence group(P>0.05);there was no difference in age between stepping speed measurement group and handgrip strength measurement group(P>0.05).2.There were no differences in taking angiotension converting enzyme inhibitor(ACEI),angiotonin receptor blocker(ARB),calcium-channel blockers(CCB),?-receptor blocker and diuretics for patients among different physical function grade groups(P>0.05),and there also were no differences in complicating with type 2 diabetes mellitus,coronary heart disease,cerebral hemorrhage and cerebral infarction(P>0.05).3.SDANN,SDANN and LF/HF in self-care group were lower than in self-care group(P<0.05),ULF and VLF in non-self-care group were higher than those in self-care group(P<0.05),triangular index in non-self-care group was lower than that in self-care group and semi-self-care group;SDANN,triangular index and LF/HF in severe dependence group were lower than those in normal group,SDANN,triangular index and LF/HF in severe dependence group were lower than those mild dependence group(P<0.05).ULF and VLF in severe dependence group were higher than those in normal group and mild dependence group(P<0.05);rMSSD,PNN50 and TP in slow stepping speed group were lower than those in normal stepping speed group(P<0.05);VLF and LF in in slow stepping speed group were higher than those in normal stepping speed group(P<0.05);the SDNN,SDNN index,rMSSD,PNN50,LF/HF in male descending handgrip strength group was lower than that in male normal handgrip strength group(P<0.05);the SDANN,MSSD,PN50 and HF in female descending handgrip strength group was lower than that in female normal handgrip strength group(P<0.05).the ULF in female descending handgrip strength group was higher than that in female normal handgrip strength group(P<0.05).4.The correlation analysis showed that ADL score,IADL score,stepping speed and handgrip strength were positively correlated with SDNN,rMSSD,PNN50,triangular index and LF/HF(P<0.05);heart rate variability index(SDNN,SDANN,triangular index,LF and HF)were correlated with heart structure and function indexes,such as LA,LVEDD and LVEF,respectively(P<0.05).5.Predictive value analysis of heart rate variability on physical function of elderly patients:SDNN,SDANN,triangular index,ULF,VLF,LF/HF had predictive value for ADL(P<0.05);SDNN,SDANN,triangular index,ULF,VLF,LF/HF had certain predictive value for IADL,but did not reach statistical difference(P>0.05);rMSSD,PNN50 had certain predictive value for stepping speed,male handgrip strength and female handgrip strength,which did not reach statistical significance(P>0.05).In addition,HF had certain predictive value for female grip strength,but did not reach statistical significance(P>0.05).Conclusion:1.The decrease of physical function was accompanied by the decrease of some indicators of heart rate variability.Physical function was positively correlated with some heart rate variability indicators,suggesting that impairment and regulation imbalance of autonomic nervous function might be related to the decline of physical function.2.The change of autonomic nervous function is consistent with the decrease of somatic function in different evaluation methods.However,the heart rate variability indexes that reflect the changes in autonomic nervous function are not completely consistent,indicating that the analysis of different heart rate variability indexes at the same time can increase the sensitivity to identify the changes in autonomic nervous function.3.The SDNN,SDANN,trigonometric index,ULF,VLF and LF/HF had certain predictive value for the activities of daily living of the elderly,suggesting that it is possible to predict the progress of the physical function of the elderly based on these indicators in the future,and to further evaluate and intervene the high-risk patients as soon as possible.4.Heart structure and function were correlated with some indicators of heart rate variability,suggesting that autonomic nervous system function might have some influence on heart structure and function.