Level of cardiovascular adaptations in children with the different types of syncope

changes which in turn depend on the basic level of functional capabilities of the cardiovascular system and its adaptation mechanisms that determine the intensity and duration of adaptive responses. Purpose - to determine the level of cardiovascular adaptations in children with syncope; to assess their relationship with some clinical, anamnestic and instrumental parameters. Materials and methods. A total of 81 children with vasovagal syncope, 25 with syncope due to orthostatic hypotension, 19 with cardiogenic syncope (aged 8-17 years) were included in our study. The control group included 41 healthy children. All patients underwent a clinical and functional examination of the cardiovascular system to determine the level of its adaptative mechanisms. Results. Children with vasovagal syncope and syncope due to orthostatic hypotension had significantly higher values of cardiac output and systolic blood volume compared to control group (p<0.05), which indicated the intensity of pumping ability of the heart. Children with syncope due to orthostatic hypotension had marked decrease in the efficiency of the heart muscle, as low values of left ventricular rate, circulatory efficiency and cardiac index compared with healthy individuals (p<0.05), as well as the trend to economize hemodynamic responses, as indicated by a significant difference between the values of the Robinson index, a decreased systolic index and the index of functional changes compared with those without syncope (p<0.05). Children with cardiogenic syncope had a significantly reduced the circulatory efficiency coefficient (p<0.05). Significant correlations were detected between the parameters of a series of integrative indicators of the adaptive mechanisms of the cardiovascular system and anamnestic, clinical, and the reports of instrumental studies in children with syncope. Conclusions. Despite the fact that children with syncope of various types had normal values for most cardiovascular indicators at rest, the tension of pumping capacity of the heart was detected, the efficiency of the cardiac muscle and circulatory efficiency were reduced, which are signs of reduced compensatory responses in children of the study groups determined. The results of the study confirm the close combination of pathogenetic mechanisms of syncope with a decrease in the adaptive mechanisms of the cardiovascular system of this category of patients. The research was carried out in accordance with the principles of the Declaration of Helsinki. The research protocol was approved by the Local Ethics Committee of the institutions mentioned in the work. Informed consent of the children’s parents was obtained for the research. No conflict of interests was declared by the authors. Key words: children, syncope, cardiovascular adaptations.