Evaluation of Heart Rate Variability in Children Presenting with Syncope

Objective: This study evaluated the diagnostic value of heart rate variability (HRV) parameters obtained from 24-hour Holter monitoring in pediatric patients with vasovagal syncope (VVS) and compared them to a control group. The study also analyzed time-domain and frequency-domain HRV parameters to explore the autonomic mechanisms underlying VVS and the diagnostic potential of HRV. Methods: This retrospective study was conducted at *** Women’s and Children’s Health Training and Research Hospital. Forty-one children with VVS and 36 healthy controls undergoing 24-hour Holter monitoring for ventricular extrasystoles were included. Comprehensive cardiac, neurological, and demographic evaluations were performed for all participants. HRV parameters were analyzed from 24-hour Holter recordings, and group comparisons were performed using the Mann–Whitney U test. Spearman correlation and Receiver Operating Characteristic analyses were also conducted. Results: Time-domain HRV parameters were significantly lower in the syncope group compared to those in the control group (p < 0.05). No significant differences were observed in frequency-domain parameters. The standard deviation of normal-to-normal RR intervals (SDNN) demonstrated the highest diagnostic accuracy, with a cut-off value of