Analysis Of Autonomic Nerve Function In Children With Vasovagal Syncope

Objective: To explore the changes of heart rate deceleration capacity(DC),heart rate deceleration runs(DRs),and heart rate variability(HRV)in children with vasovagal syncope(VVS),and analyze the predictive value of DC in the diagnosis of VVS.Methods: Select 45 children who were diagnosed with VVS in our hospital during the period from 2018.01.01 to 2019.12.31 as the VVS group,and 45 healthy children,who came for physical examination,were selected as the control group.24 h dynamic electrocardiogram was performed and the changes of basic DC value,DRs and HRV indexes of children with VVS and healthy children were compared,and again grouped by age and gender;at the same time analyzed the correlation between DC and HRV indexes,and the predictive value of DC in the diagnosis of VVS.Results: Among the study subjects,45 cases were in the VVS group and 45 cases were in the control group.1.VVS classification: Among 45 children with VVS,27 cases(60%)were vasodepressor VVS(VVS-VI),0 cases werecardioinhibitory vasovagal syncope(VVS-CI)and 18 cases weremixed type VVS(VVS-M).2.Comparison of the DC,DRs and HRV of the VVS group and the control group:The ratio of low frequency power to high frequency power(LF/HF),DC,and DR8 in the VVS group were significantly higher than those in the control group(P<0.05).3.Changes of DC,DRs,and HRV indexes with age and gender: In the VVS group,compared with school-age children,DC,DR4 and low frequency power(LF)of adolescent children were significantly higher(P<0.05).However,DC,DRs,and HRV of male and female children were no significant difference in each index(P>0.05).The control group was grouped by age and sex and there was no significant difference in DC value,DRsand HRV indexes(P>0.05).4.Comparison of HRV,DC,and DRs between the VVS group and the control group at school-age and adolescence:In school-age,the DC of children in the VVS group was significantly higher than the control group(P<0.05);during adolescence,the DC value,DR4,DR8 and LF of the VVS group were significantly higher than the control group(P<0.05).5.The correlation between DC and HRV indexes:DC and multiple indexes of HRV showed significant positive correlation(r=0.31～0.67,P<0.05),while DC and LF/HF were significantly negatively correlated(r=–0.36,P <0.05).6.The predictive value of DC in the diagnosis of VVS: The binary Logistic regression analysis was performed on the statistically significant independent variables in school-age and adolescent children respectively,and it was found that only DC was correlated with VVS in school-age and adolescent children.The ROCwas used toanalyze the predictive value of DC,and it was found that when the DC value of school-age is 7.72 ms as the cutoff value and the DC value ofthe adolescent is 8.36 ms as the cutoff value,there was a higher sensitivity and specificity.Conclusion: The autonomic nerve function was abnormal in asymptomatic stage of VVS children,and it became more significant with age.Both school-age and adolescent children with VVS had increased vagus nerve tension,and adolescent VVS children had a certain degree of increased sympathetic nerve tension.The DC has an obvious positive correlation with vagus nerve tension and has a good predictive value for the diagnosis of VVS.