Predictive Value Of Heart Rate Variability In Patients With High-risk Acute Coronary Syndrome And Its Relationship With Changes In Cardiac Structure And Function

Objective:To compare the heart rate variability?HRV?indices between normal subjects and patients with acute coronary syndrome?ACS?with different risk stratification,and to obtain the characteristics of heart rate variability in patients with high-risk ACS.At the same time,the cardiac structural and functional indexes of high-risk ACS patients were measured,and the correlation between heart rate variability and cardiac structural and functional indexes of high-risk ACS patients was analyzed.In addition,this study also explored the relationship between the occurrence of malignant ventricular arrhythmias and heart rate variability in patients with ACS.Methods:260 patients with ACS admitted from August 2016 to August 2018 were divided into low-risk group?<85 points,n=76?,medium-risk group?<85-133 points,n=82?and high-risk group?>133 points,n=102?according to the GRACE score of patients at admission.At the same time,90 healthy people in the same period of our hospital were selected as normal control group.All subjects completed 24h continuous dynamic electrocardiogram monitoring and echocardiography within 24 hours of admission,and compared HRV and cardiac structural and functional indexes of each group.The cardiac structural and functional indexes of high-risk ACS patients were measured,and the correlation between heart rate variability and cardiac structural and functional indexes of high-risk ACS patients was analyzed.According to the results of24h electrocardiogram monitoring,ACS patients were divided into malignant ventricular arrhythmia positive group?n=137?and malignant ventricular arrhythmia negative group?n=123?.The HRV indexes of the two groups were analyzed to explore the relationship between the occurrence of malignant ventricular arrhythmia and heart rate variability in patients with ACS.Results:There were no significant differences in the general data of age,sex,history of hypertension,history of diabetes,history of smokingamong the four groups?P>0.05?.In ACS patients,the levels of SDANN,SDNNI,rMSSD,PN₅₀0 and HF were lower than those in the normal control group,and with the increase of risk stratification,the above indicators decreased more significantly?P<0.05?.The LF/HF of ACS patients was higher than that of the normal control group,and the increase was more significant with the increase of risk stratification?P<0.05?.The left atrial diameter?LA?and left ventricular end-diastolic diameter?LVEDD?in high-risk group were larger than those in medium-risk group,low-risk group and normal control group,and the left ventricular ejection fraction?LVEF?in high-risk group was lower than that in medium-risk group,low-risk group and normal control group?P<0.05?.SDNN was negatively correlated with LA and LVEDD and positively correlated with LVEF in high-risk group;SDANN was negatively correlated with LA and LVEDD and positively correlated with LVEF in high-risk group;SDNNI was negatively correlated with LVEDD and positively correlated with LVEF in high-risk group;rMSSD was positively correlated with LVEF in high-risk group;HF was negatively correlated with LVEDD and positively correlated with LVEFin high-risk group?P<0.05?.The SDNN,SDANN,SDNNI,rMSSD,PNN₅₀0 and HF of the malignant ventricular arrhythmia positive group were lower than the malignant ventricular arrhythmia negative group?P<0.05?.Conclusions:The decrease of heart rate variability in high-risk ACS patients indicates serious impairment of cardiac autonomic nervous function.HRV indexes can detect high-risk ACS patients earlier,and to some extent reflect the severity of ventricular remodeling and impaired cardiac function,so that clinicians can open the diseased vessels as soon as possible and reduce the occurrence of major adverse cardiovascular events?MACE?.