[The relationship between anxiety and vasovagal syncope in children and its impact on autonomic nervous function]

Objective: To explore the correlation between anxiety and the vasovagal syncope (VVS) in children and the impact of anxiety on the autonomic nervous function in pediatric VVS patients. Methods: A cross-sectional study was conducted. From January 2022 to October 2024, a total of 81 children diagnosed with VVS by head-up tilt test (HUTT) from the Department of Pediatric Cardiology, Capital Center for Children's Health, Capital Medical University were retrospectively enrolled. The VVS symptoms were quantified. The emotional state was evaluated using the screen for child anxiety related emotional disorders (SCARED). Autonomic nervous function was evaluated by the heart rate variability (HRV). According to the HUTT results, VVS children were categorized into vasoinhibitory type (VVS-VI), cardioinhibitory type (VVS-CI) and mixed type (VVS-M). The anxiety scores of VVS children were evaluated and the differences in anxiety scores among different subtypes were analyzed. According to the SCARED results, VVS children were divided into anxiety group and non-anxiety group. General characteristics, VVS symptoms scores, and HRV indicators were compared between the two groups. The comparison between groups was performed using independent sample t test, Mann-Whitney U test, Kruskal-Wallis H test, and chi-square test. Correlation analysis was completed using Spearman correlation analysis. Results: Among 81 VVS children, there were 31 males and 50 females, with the age of (11.6±2.0) years. The scores of somatization or panic, generalized anxiety disorder, separation anxiety disorder, social phobia, school phobia and the total score of anxiety in VVS children were 5.0 (2.0, 10.0), 5.0 (2.0, 9.0), 4.0 (2.0, 7.0), 5.0 (3.0, 8.0), 1.0 (0, 3.0) and 22.0 (13.0, 38.0). There were 40 cases of anxiety, accounting for 49% and 41 cases without anxiety, accounting for 51%. There was a significant difference in separation anxiety between VVS subgroups (P<0.05). Compared with the non-anxiety group, the anxiety group had a lower score of syncope symptom and a higher score of palpitation symptom (both P<0.05). Anxiety was positively correlated with palpitation score (r=0.25, P=0.011). Anxiety score was negatively correlated with syncope symptom score (r=-0.26, P=0.008), and positively correlated with chest tightness and palpitation symptom score (r=0.23, 0.26, both P<0.05). For HRV indices, the anxiety group showed significantly higher values in standard deviation of all normal-to-normal intervals, standard deviation of the average sequential 5 min normal-to-normal interval means and low-frequency power compared with the non-anxiety group (all P<0.05). Conclusions: The prevalence of anxiety in children with VVS is high and its manifestations are diverse. Those with VVS and comorbid anxiety have fewer syncope episodes but more palpitations. Children with VVS and comorbid anxiety exhibit an overall enhanced autonomic nerve tension, mainly sympathetic nerve activation.