Diagnostic Value Of Heart Rate Variability In Vasovagal Syncope In Children

Objective :The diagnostic value of heart rate variability（HRV）in children with vasovagal syncope（VVS）was studied by measuring heart rate variability（HRV）in children with vasovagal syncope（VVS）.Methods:A total of 60 children with VVS diagnosed in the Children’s diagnosis and treatment Center of Xuzhou Central Hospital from September 2019 to May 2021 were divided into syncope test group,head-up tilt test（head-uptilttabletest,HUTT）and dynamic electrocardiogram monitoring,including 33 males（55%）and 27 females（45%）.The average age was（11.15±4.97）years old.At the same time,60 healthy children were selected as the control group,including 32 males（53.3%）and 28 females（46.7%）.The average age was（10.70±2.46）years old.The difference of HRV between the two groups was compared to analyze the diagnostic value of HRV in children’s VVS.Results:（1）compared with male children,the time domain and frequency domain indexes of female children in VVS group were lower,but there was no significant difference between female children and male children.（2）In the healthy children group,the time domain indexes SDNN,p NN50（%）,r MSSD and frequency domain indexes HF and VLF decreased slightly,while the time domain indexes TI,SDNNi and frequency domain index LF increased slightly.The difference was not statistically significant.（3）In VVS group,the time domain indexes SDNN,TI,SDNNi,r MSSD and frequency domain indexes HF and VLF were slightly lower,while the time domain indexes p NN50（%）and frequency domain index LF were slightly higher in children under 12 years old than those in children ≥12 years old.The difference was not statistically significant.（4）In the healthy children group,compared with children ≥ 12 years old,the time domain indexes SDNN,p NN50（%）,TI and frequency domain indexes LF and VLF of children <12 years old decreased slightly,while the time domain indexes SDNNi,r MSSD and frequency domain indexes HF increased slightly.The difference was statistically significant in HF.（5）The time domain indexes SDNN,p NN50（%）and TI in VVS group had no significant change compared with the control group,and the difference was not statistically significant.The time domain indexes SDNNi and r MSSD in VVS group were significantly increased,and the frequency domain indexes LF,HF and VLF were significantly increased.Compared with healthy children group,the difference was statistically significant.（6）There was no significant difference in time domain indexes SDNN,p NN50（%）and TI between the positive group and the negative group.The time domain indexes SDNNi and r MSSD in the positive reaction group were significantly increased,and the frequency domain indexes LF,HF and VLF were significantly increased.Compared with the negative reaction group,the difference was statistically significant.（7）There was no significant difference in time domain indexes SDNN,p NN50（%）,TI,SDNNi,r MSSD and frequency domain indexes LF,HF and VLF among children with syncope of mixed type,cardiac inhibitory type and vascular inhibitory type.（8）ROC curve analysis the sensitivity and specificity of SDNNi,r MSSD,LF,HF and VLF for predicting HUTT diagnosis of VVS were0.710、0.741、0.780、0.786 and 0.831,95%CI were（0.547,0.873）、（0.602,0.880）、（0.609,0.951）、（0.663,0.909）and（0.713,0.949）,respectively.It is suggested that SDNNi,r MSSD,LF,HF and VLF have certain value in the diagnosis and prediction of HUTT.Different SDNNi,r MSSD,LF,HF and VLF values were used as cutoff points to analyze the sensitivity and specificity of predicting HUTT diagnosis.It was found that LF,HF and VLF had higher sensitivity and specificity for predicting HUTT diagnosis.When the cutoff values of LF,HF and VLF,496,867.5 and 865.5 were used as cutoff values,the prediction effect of the positive rate of diagnosis was better,the sensitivity was85%,62% and 68% respectively,and the specificity was 63%,88% and 84%,respectively.Conclusion:（1）The related indexes of HRV may predict the positivity of HUTT test,which is closely related to predicting the positivity of HUTT test.（2）HRV can be used as a non-invasive examination to predict the sensitivity and specificity of HUTT in the diagnosis of VVS.