Diagnostic value of functional tests for determining autonomic system balance in children with respiratory pathology

Holter monitoring of electrocardiogram (ECG) is a modern method for assessing the balance of the autonomic nervous system (ANS) and its impact on the activity of the cardiovascular system. Heart rate variability (HRV), as a characteristic of heart rate fluctuations of R-R intervals, reflects the balance of the ANS. The diagnostic value of the method increased by cardiovascular reflex tests, such as orthostatic, breath holding, Valsalva maneuver. Aim - to determine the diagnostic sensitivity and capabilities of functional tests in the process of ECG monitoring to assess the balance of autonomic innervation in children in the model of acute bronchitis. Materials and methods. The study examined 35 children aged 12-15 years: 15 children with acute bronchitis and 20 clinically healthy individuals. The ANS balance assessed by the data of short-term Holter monitoring of the background ECG and with the following tests: orthostatic and Valsalva. Heart rate variability assessed by heart rate variance dispersion. Results. The paper analyzes of HRV indicators which have a clear physiological basis, such as the measure of the central tendency of the RR interval, indicators of variance (SDNN), heart rhythm concentration (rMSSD) and the level of parasympathetic effects on the heart rhythm (pNN50). A significant difference between the data obtained in children with bronchitis relative to the clinically healthy persons. The possibility of the assessing autonomic balance in an individual patient according to the data obtained with an orthostatic test and interval analysis with a Poincaré graph is shown. Conclusions. Assessment of the balance of the ANS using Holter monitoring of ECG with a short recording is a modern method for diagnosing its disorders. In acute bronchitis, the most sensitive indicators are the rMSSD and the pNN50. The use of functional tests during short-term Holter monitoring of ECG recording expands the diagnostic capabilities of the method. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.