Heart rate variability and trait anxiety in children with irritable bowel syndrome: is there a link?

Aim. The aim of current study was to evaluate parameters of heart rate variability and their correlation with the levels of anxiety in children with irritable bowel syndrome. Materials and methods. We enrolled 22 children aged 6–12 years with verified diagnosis of irritable bowel syndrome according to the Rome criteria IV. The control group included 10 children of the same age and sex. The CMAS (Children’s Manifest Anxiety Scale) test was used for evaluation of the trait anxiety level. A non-invasive method of heart rate variability is used as a transdiagnostic biomarker of neurohumoral regulation and, thus, of the stress resistance. Time and frequency domain parameters of heart rate variability were studied in 5 min ECG-recordings in supine position. Data were processed using Microsoft Excel 2016 and analyzed with GraphPad (Prism 5.0). Results. Children with irritable bowel syndrome had significantly 1.7-fold higher levels of trait anxiety and 2.2-fold lower values of heart rate variability parameters as compared to the control group. In addition, reduced sympathetic (LF) activity was accompanied by upregulation of neurohumoral component (VLF) and parasympathetic (HF) activity. A positive correlation between parameters of heart rate variability and trait anxiety was found in children with irritable bowel syndrome. Conclusions. Children with irritable bowel syndrome were shown with increased levels of trait anxiety. Reduction in heart rate variability and changes of its spectral structure were suggestive about the dysregulation in the gut-brain axis with reduction of the autonomic activity and predominance of neurohumoral regulation. In summary, our study has provided important information about the pathophysiology of irritable bowel syndrome in children.