Predictive Value Of Ventricular Repolarization Parameters In The Diagnosis Of Vasovagal Syncope In Children

Objective:To explore the predictive value of ventricular repolarization parameters in the diagnosis of vasovagal syncope(VVS)in children.Method:From January 2020 to September 2022,children who were admitted to the Department of Cardiology,Children’s Hospital Capital Institute of Pediatrics for syncope or presyncope and completed the head-up tilt test(HUTT)were collected.Grouping according to HUTT results:①VVS group for HUTT-positive,control group for HUTTnegative;②The VVS group was divided into vascular inhibition type,cardiac inhibition type and mixed type according to the changes of blood pressure and heart rate(HR)during HUTT.③The VVS group was divided into malignant VVS group and non-malignant VVS group according to whether there was sinus arrest over 3 seconds during HUTT.The demographic characteristics,laboratory indexes and ventricular repolarization parameters of each group were evaluated and compared.This study used logistic regression analysis to investigate the potential risk factors associated with VVS in children.A decision tree model was constructed to predict the diagnosis of vasovagal syncope in children.The predictive value of the model was evaluated by receiver operating curve.Results:1.Altogether 241 consecutive patients were enrolled,including 189 in the VVS group and 52 in the control group.The HUTT positive group included 96 patients(50.8%)with vascular inhibition type,28 patients(14.8%)with cardiac inhibition type and 65 patients(34.4%)with mixed type.2.The VVS group was older than the control group(P<0.05).No significant difference was found in gender between the two groups.The albumin(Alb)and HR in VVS group were lower than those in control group,and QTmax,QTd and QTcd were longer than those in control group(P<0.05).3.QTd and QTed were independent risk factors for VVS in children as showed by multivariate logistic regression analysis,and body mass index(BMI)and Alb were protective factors for VVS.The decision tree model results show that QTd,Alb,HR and BMI can be used for clinical decision-making.The area under the ROC curve of the decision tree model for predicting vasovagal syncope was 0.862.and the accuracy rate of it was 82.2%.4.There was no significant difference in age,sex and BMI between VVS vascular inhibition type,cardiac inhibition type and mixed type(P>0.05).The levels of Tp-Te,TpTe/QT and Tp-Te/QTc in children with cardiac inhibition type were higher than those in the other two groups(P<0.05).5.There were 7 cases(3.7%)of malignant VVS,and no significant difference was found in ventricular repolarization parameters between children with malignant and nonmalignant VVS group(P>0.05).Conclusion:QTd and QTcd are independent risk factors for VVS.The decision tree model showed that QTd,Alb,HR and BMI were the influential factors of VVS in children,and the decision tree model had a good predictive value in children with VVS.