Predictor of Syncopal Recurrence in Children With Vasovagal Syncope Treated With Metoprolol

Abstract

Objective: To explore the predictors for syncopal recurrence in a pediatric population with vasovagal syncope (VVS) treated with metoprolol.

Study design: This study was conducted retrospectively among children suffering from VVS with or without syncopal recurrence. Data on the detailed medical history and auxiliary examinations were obtained from the electronic medical records. The risk factors for syncopal recurrence were studied by cox regression analyses and the corresponding best cutoff values were determined using receiver operating characteristic analysis. Kaplan-Meier curves were plotted to determine the trends of the syncopal recurrence-free survival rate.

Results: Forty-two consecutive VVS children were enrolled in the study. At the end of a median follow-up duration of 9.0 (4.8, 19.1) months, 12 patients (29%) experienced ≥1 syncopal episode. Cox regression analyses revealed that the number of previous syncopal episodes before treatment was a risk factor for syncopal recurrence (hazard ratio = 1.027, 95% confidence interval 1.009 - 1.045, P = 0.003). Moreover, 4 previous syncopal episodes were certified as the best cutoff value, and the Kaplan-Meier curves showed that the syncopal recurrence-free survival rate over time in patients with > 4 previous syncopal episodes was significantly lower than that in patients with ≤4 episodes (P = 0.019 at the log-rank test).

Conclusion: In a pediatric population with VVS while on the treatment of metoprolol, the number of previous syncopal episodes before treatment played a significant role in predicting syncopal recurrence.

Keywords: children; metoprolol; predictor; syncopal recurrence; vasovagal syncope.

FIGURE 1

Number of patients with different syncopal episodes before treatment. The y-axis represents the number of patients; the x-axis represents the number of previous syncopal episodes before treatment. The median frequency was 4.0 episodes/person/year.

FIGURE 2

Trend of the syncopal recurrence-free survival rate in all eligible patients over time. The y-axis represents the survival rate for non-recurrence of syncope; the x-axis represents follow-up duration.

FIGURE 3

Receiver operating characteristic curve for determining the best cutoff for the number of previous syncopal episodes in predicting syncopal recurrence. The y-axis represents the sensitivity to predict the recurrence of syncope; the x-axis represents the false-positive rate (100%–specificity%). The 45 reference line of the chart indicates that the sensitivity and the false-positive rate are equal. The area under the curve was 0.743 with a 95% confidence interval 0.574 to 0.912 (P = 0.015).

FIGURE 4

Kaplan–Meier curve analysis of the syncopal recurrence-free survival rate between patients with >4 previous syncopal episodes and with ≤4 previous sycopal episodes. The y-axis represents the survival rate for non-recurrence of syncope; the x-axis represents follow-up duration. The recurrence-free survival rate of syncope in patients with >4 previous syncopal episodes before treatment was significantly lower than that of patients with ≤4 episodes (P = 0.019 at the log-rank test).