Association Of Delta Power During NREM Sleep With Autonomic Nerve Function And Prognosis In Patients With Heart Failure And Insomnia

BackgroundHeart failure is a complex clinical syndrome with long course,poor prognosis and high mortality.Insomnia is common among patients with heart failure,which can promote the progression of heart failure and affects its long-term prognosis.Previous studies proposed that insomnia can lead to abnormal change in EEG power spectrum and there is a certain correlation with HRV.However,the effect of heart failure with insomnia on EEG power spectrum and its relationship with HRV are still unclear.And there is also a lack of research on the association between EEG power spectrum and the prognosis of heart failure.ObjectivesThe aims of this study were:1)investigate the effect of insomnia on the EEG power spectrum of patients with heart failure and its association with HRV through subjective and objective sleep examination and ECG;2)explore the association between specific frequency band in EEG power spectrum and the prognosis of heart failure.MethodsThe information of patients with heart failure who hospitalized in the Department of Cardiovascular Medicine,The First Affiliated Hospital of Xinxiang Medical College and met the inclusion criteria were collected from April 2019 to December 2021.Then these patients were divided into insomnia group（53 cases）and non-insomnia group（80cases）according to whether they had insomnia.General clinical data,sleep and psychological questionnaire,echocardiography,24-hour dynamic electrocardiogram of the two groups were collected and compared.All the participants were monitored by PSG overnight to evaluate the macroscopic sleep structure and analyze EEG power spectrum.The patients were followed for one year,and the end points were defined as heart failure death and readmission.Results1 A total of 133 patients with heart failure were enrolled in this study.87 males（65.4%）and 46 females（34.6%）with an average age of 60.9±12.8 years.Among them,79 cases（59.4%）had complicated with hypertension,97 cases（72.9%）had coronary heart disease,37 cases（27.8%）had diabetes and 23 cases（17.3%）had cerebrovascular disease.Compared with non-insomnia group,patients with insomnia had higher scores of HAD,PSQI,ESS and FS-14,and higher proportions of positive inotropic drugs and sedative-hypnotic drugs（all P<0.05）.2 HRV analysis:Time domain analysis found that SDNN and trigonometric index of the two groups were lower than the reference value.However,there were no significant differences between the two groups in SDNN,SDNN-index,p NN50 and triangular index（all P>0.05）.Frequency domain analysis showed no significant difference in each band spectrum between 2 groups（all P>0.05）.3 PSG monitoring:PSG provided varying degrees of disordered sleep structure in both groups.Compared with non-insomnia group,patients with insomnia had lower SE,longer sleep latency in REM stage and higher proportion in W stage（all P<0.05）.There were no significant differences in TST,SL,WASO,etc.between 2 groups（all P<0.05）.Five-minute EEG power spectrum analysis indicated that Delta power in insomnia group was significantly lower than that in non-insomnia group（P<0.05）.The power of Alpha,Beta,Gamma and Theta bands between the two groups have no statistical significances（all P>0.05）.4 Correlation between EEG power spectrum and HRV:Spearman’s correlation analysis showed that there was no significant correlation between 5-minute EEG power spectrum（Delta,Alpha,Beta,Gamma and Theta）and HRV indexes（SDNN,SDNN-index,p NN50,triangular index,HFnu,LFnu,LF/HF）（all P>0.05）.5 Association between Delta power and the prognosis of heart failure:This study followed 133 patients,up to December 2021,131 cases were followed up,with a loss to follow-up rate of 1.5%.After excluding patients with invalid EEG data,100 patients participated in this analysis.Dichotomous grouping at the first quartile of Delta power with Q1 group（Delta power<51.7μV~2/Hz）and Q2-Q4 group（51.8-378.5μV~2/Hz）,and perform Kaplan-Meier（KM）survival analysis and COX regression analysis.KM survival analysis showed that the incidence of end-point events in the Q1 group was much higher than that in the Q2-Q4 group after one year,with statistical significance（P=0.025）.After adjusting for relevant confounders（gender,age,comorbidities and medication,etc.）,COX regression analysis found that the Delta waves was still significantly associated with a higher risk of heart failure death and readmission[HR3.665（1.466,9.162）,P=0.005].ConclusionThis study confirmed a high incidence of insomnia in patients with heart failure.EEG analysis showed excessive hyperarousal during sleep in patients with heart failure and insomnia,which was mainly manifested by the decrease of Delta power during NREM sleep,and Delta power could be used as a new indicator of the prognosis of heart failure death and readmission.