| BackgroundViral myocarditis(VMC)is a disease in which viral infection leads to myocardial interstitial inflammatory infiltration and necrosis of adjacent myocardial cells,leading to cardiac dysfunction and other system damage.It is a common cardiovascular disease in children.Clinically,the children of VMC are prone to combine with arrhythmias and premature ventricular beats(VPB)is the most common.The long-term frequent high load and complex premature ventricular beats tend to aggravate myocardial damage.Heart rate variability is a measure of the change in R-R between successive heart rate in cardiac cycle.It is a quantitative non-invasive assessment of cardiac sympathetic nerve,vague nerve and its balance.Common indicators of HRV in clinical practice include time domain indicator(SDNN,SDANN,RMSSD and PNN50)and frequency domain indicators(HF,LF and LF/HF).HRV analysis has been widely used in risk prediction and risk stratification of clinical cardiovascular disease.ObjectiveThe purpose of this study was to investigate the relationship between HRV index and premature beat load and complexity in children of VMC complicated with VPB,to explore the changes of autonomic nerve function in children of VMC complicated with VPB,and to provide reference for the clinical diagnosis,treatment and risk of VMC complicated with VPB.MethodsThe 288 case of VMC complicated with VPB were selected from January 2016 to December 2018 visited in the First Affiliated Hospital of Zhengzhou University as experimental group,95 healthy children were selected as normal control group.HRV time domain index and frequency domain index were monitored by 24-hour dynamic electrocardiogram.According to the age,the children were divided into different stage,children of all ages were divided into different groups by different load(24-hour VPB number as a percentage of the total heart rate)and Lown grade.The differences of HRV were compared between different groups.Spearman rank correlation analysis was used to compare the correlation between the HRV and the load of VPB in VMC.Results1.Comparison of HRV indexes between children with VMC complicated with VPB(experimental group)and normal control group: In the infant period,the HRV index SDNN,SDANN,PNN50,HF,LF and LF/HF were lower in the experimental group than in the normal control group(P all<0.05).In the preschool age period,the HRV index SDNN,SDANN,PNN50,LF and LF/HF were lower in the experimental group than in the normal control group(P all<0.05).In the school age period,the HRV index SDNN,PNN50,LF and LF/HF were lower in the experimental group than in the normal control group(P all<0.05).2.In the infant period,the HRV index RMSSD,PNN50,HF,LF and LF/HF were lower in high-load group than low-load group(P all<0.05);the HRV index PNN50 and HF were lower in high-load group than median-load group(P all<0.05);the HRV index LF/HF was lower in median-load group than low-load group(P all<0.05).In the preschool age period,the HRV index SDNN,SDANN,RMSSD,LF and LF/HF were lower in high-load group than low-load group(P all<0.05);the HRV index SDANN and RMSSD were lower in high-load group than median-load group(P all<0.05);the HRV index SDNN,LF and LF/HF were lower in median-load group than low-load group(P all<0.05).In the school age period,the HRV index SDNN,PNN50,HF,LF and LF/HF lower in high-load group than low-load group(P all<0.05);the HRV index SDNN,HF and LF were lower in high-load group than median-load group(P all<0.05);the HRV index LF and LF/HF were lower in median-load group than low-load group(P all<0.05).3.In the infant period,the load of VPB were negatively correlated with HRV index SDNN,RMSSD,PNN50,LF and LF/HF(r =-0.284,-0.336,-0.429,-0.352,-0.500,P<0.05).In the preschool age period,the load of VPB were negatively correlated with HRV index SDNN,LF and LF/HF(r =-0.251,-0.254,-0.430,P<0.05).In the school age period,the load of VPB were negatively correlated with HRV index SDNN,SDANN,RMSSD,PNN50,HF,LF and LF/HF(r =-0.438,-0.260,-0.222,-0.249,-0.183,-0.547,-0.670,P<0.05).4.In the infant period,the HRV index SDNN,RMSSD and PNN50 were lower in the L3-L5 group than the L1-L2 group(P all<0.05).In the preschool age period,the HRV index SDNN,SDANN,RMSSD,PNN50,LF and LF/HF were lower in the L3-L5 group than the L1-L2 group(P all<0.05).In the school age period,the HRV index RMSSD,PNN50 and LF/HF were lower in the L3-L5 group than the L1-L2 group(P all<0.05).Conclusion1.The autonomic nervous function of VMC complicated with VPB in children is significantly impaired,mainly vague nerve function,and sympathetic-vague nerve balance is disrupted.2.With the increase of load and complexity of VPB in VMC,the sympathetic and vagal nerves and its balance disorders increased.3.HRV index can provide a reference for the severity of VMC complicated with VPB in children. |
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