The aim of the study was to improve the early diagnosis and prognosis of cardiac dysfunction in children with reduced exercise tolerance, taking into account the somatotype, hemodynamic features, endothelial function, the state of stress- realizing and stress-limiting systems.To perform the tasks, 120 adolescents with cardiac pathology((arterial hypertension (AH), disturbances in the rhythm and conduction of the heart) and systemic connective tissue dysplasia (CTD), aged 11-17 years,were observed.
All tested adolescents with cardiac pathology clinical, anthropometric, instrumental studies, a clino-orthostatic test, Rufier’s test, "6-minute walk" were performed; vascular endothelial function was determined by occlusion tests; the daily excretion of catecholamines in the urine was determined by the fluorometric method - adrenaline, norepinephrine; serotonin content in the blood, the lactate content, the cortisol content in the blood were determined.
In order to assess the general situation regarding to physical activity and exercise tolerance of modern children, 342 schoolchildren of two schools in the city of Kharkiv were studied.
In the first stage, physical activity and exercise tolerance were assessed in children who studied in secondary school, as well as in patients who had high blood pressure, small abnormalities in heart development and signs of CTD. Children with obesity and thyroid pathology were excluded from the study. It was found 41.5 % of healthy schoolchildren had reduced exercise tolerance, in 88.9 % of cases unsatisfactory results were shown by physically inactive children. In adolescents with AH decreased tolerance was observed in 65.1 %, in children with CTD - in 51.0 % of cases.
The analysis of morphofunctional characteristics of the heart, indicators of general hemodynamic and vascular endothelial function in children with reduced exercise tolerance was performed, taking into account the nature of somatic pathology and physical activity of patients. It was found that reduced adaptive capacity often recorded in adolescents with low physical activity and more clearly observed in children with AH. However, in boys with AH reduction in exercise tolerance was combined with the initial signs of the cardiac remodeling. Insufficient endothelium-dependent vasodilation was observed both, on the background of AH and CTD, in 57.9 % of adolescents.
At the second stage, the indicators of neurohumoral regulatory systems were analyzed. It was found that the decreased exercise tolerance is accompanied by an increase in cortisol levels and a decrease in serotonin levels in the blood, both among children with AH and with CTD. The relationship between anthropometric parameters, functional characteristics of the cardiovascular system and indicators of neurohumoral regulation and significant factors in ensuring of adequate adaptive response were identified.
At the final stage of the study, the principles of increasing physical activity in children with AH, secondary cardiomyopathies and CTD were substantiated. An algorithm for monitoring children with reduced adaptability has been developed.
