Relationship Between Circadian Rhythm Of Heart Rate And Dysfunction Of Autonomic Nervous System In The Elderly With Four Common Diseases

Background and aim：With the improvement of living standard and increasing longevity，manycountries have entered the aging society. The advent of aging society has beenaccompanied by an increasing demand for medical care and brought great pressureand burden to our society. How to optimize the treatment, distribute medical resourcesrationally, and improve the quality of life in the elderly are the common problems weare facing. Coronary heart disease, hypertension, diabetes mellitus，benign prostatichyperplasia have become four common diseases in the elderly and affected the qualityof family life seriously. The aim of this study is to identify potential links betweencircadian rhythm of heart rate and dysfunction of autonomic nervous system in theelderly with above four common diseases by measuring circadian rhythm of heart rateand heart rate variability through the24-hour ambulatory electrocardiogram. Thereason to suspect such links rely on the fact that these common diseases exhibitincreased major adverse cardiac events. This may be due to the dysfunction of theautonomic nervous system which is the common process in above four diseases’occurrence and development. Hence, it is tempting to conduct this study and thisstudy may provide a basis for the prognosis prediction and treatment optimization ofcommon diseases in the elderly.Methods：A total of144subjects，aged60years or higher（average75.67±9.10years），who completed24-hour ambulatory electrocardiogram between August2014andFebruary2015in Geriatrics department of the First Affiliated Hospital of JilinUniversity were selected to this study. They were divided into A（not suffering from common disease,n=11）、B（suffering from one common disease, n=36）、C（sufferingfrom two common diseases, n=59）、D（suffering from three or four common diseases,n=38） four groups according to the number of diseases they were suffering from.Coronary heart disease， hypertension, diabetes mellitus and benign prostatichyperplasia were incorporated into this study. Daytime average heart rate, nocturnalmean heart rate,24-hour average heart rate, circadian rhythm of heart rate, circadianrhythm index of heart rate, SDNN, rMSSD, SDANN, triangle index were determinedto evaluate the function of autonomic nervous system. Data were analyzed usingSPSS17.0statistical software (SPSS17.0). A value of P <0.05was consideredstatistically significant.Results：The degree of abnormality of circadian rhythm of heart rate was positivelycorrelated to the number of the diseases that subjects were suffering from（r=0.611，P＜0.05）.The Sex ratio, nocturnal mean heart rate and24-hour average heart rate didnot show markedly differential in statistics（P＞0.05）. Daytime average heart rate,circadian rhythm index of heart rate, SDNN, rMSSD, SDANN and triangle indexdecreased regularly from group A to D（P＜0.05）, while age and the proportion ofusing drug increased regularly from group A to D（P＜0.05）.Conclusions：1、The elderly have lower circadian rhythm index of heart rate and more seriousdysfunction of autonomic nervous system when they have more common diseaseswhich includes coronary heart disease，hypertension, diabetes mellitus and benignprostatic hyperplasia.2、The elderly have lower heart rate variability and more serious dysfunction ofautonomic nervous system when they have more common diseases which includescoronary heart disease， hypertension, diabetes mellitus and benign prostatichyperplasia.3、The trend of change in circadian rhythm of heart rate is consistent with heartrate variability. 4、Simultaneous determination of the circadian rhythm of heart rate and heartrate variability through24-hour ambulatory electrocardiogram may improve the earlydetection rate of dysfunction of autonomic nervous system.