Heart Rate And Heart Rate Variability Relation To Heart Failure And Prognosis

Objective To explore whether the heart rate and heart rate variability relation to heartfailure and prognosis.Methods The245chronic heart failure patients admitted in Genearl Hospital of NingxiaMedical University between Octber2010and June2012were enrolled in this study. Mean heart rate at rest was categorized into predefined groups: A group (50-70beats/min), B group (71-90beats/min), and C group (＞90beats/min). After one year follow-up, the clinical data of230patients was collected.97patients among them performed a holter monitoring. Based onfunctional classifications, they were divided into class Ⅰ, Ⅱ, Ⅲ, Ⅳgroup,based on leftventricular ejection fraction(LVEF),they were divided into LVEF≥30%and LVEF＜30%group,and26healthy one as comparison. Heart rate variability indexs including standarddeviation of all normal RR interval (SDNN), standard deviation of the5-minute average RRinterval (SDANN), the percentage of intervals＞50ms different from preceding interval(PNN50), square root of the mean of the squares of successive RR interval differences(RMSSD) was collected.Rusults1.With increased heart rate, ejection fraction decreased significantly andreadmission and mortality rised up at the end of follow-up（P＜0.01）.2.After survivalanalysis clinical data of patients with different heart rate using Cox’s regression model, wefound a reverse association between heart rate and survival.3. Logistic regression analysismortality in patients with heart failure: Heart rate is an independent risk factor for mortality in patients with heart failure（OR﹦1.102,95%CI:1.059～1.146,P﹤0.01）.4.Compared to thecontrol group, heart rate variability indexs (SDNN, SDANN, PNN50, RMSSD) of heartfailure patients decreased (P＜0.01or P＜0.05).5. Heart rate variability indexes in differentcardiac function:With the severity of heart failure, SDNN, SDANN, PNN50and RMSSDdeclined significantly（P＜0.01）.6.Compared to LVEF≥30%group, heart rate variabilityindexs (SDNN, SDANN, PNN50, RMSSD) of LVEF<30%group decreased (P＜0.01or P＜0.05).Conclusion1.Heart rate as a prognostic risk factor in patients with heart failure. Withincreased heart rate, ejection fraction decreased significantly and readmission and mortalityrised up at the end of follow-up.2.Increased heart rate with worse survival in patients withheart failure. Heart rate is an independent risk factor for mortality in patients with heartfailure,and heart rate of>90b.p.m is a risk factor with heart failure.3.Patients with heartfailure have autonomic dysfunction and a decreased heart rate variability.4.The change ofheart rate variability is associated with the severity of heart failure and cardiacfunction.Decreased heart rate variability is associated with worse heart function.