[Evaluation of the phase changes in cardiac activity in respect of age]

A comparative analysis is made of the chronocardiometric indicators among teenagers with a special reference to the age factor. The presence of phasic syndromes is established by the type of hyper- and hypodynamia of the myocardium in 22.3 per cent average of the children under study. Up to the 15th year of life, the diseases characterized by hyperdynamia show a two-times higher incidence in comparison with hypodynamia cases. In the 16 to 17-year age group the ratio is altered and accordingly reveals a predomination of hypodynamia conditions. Development of phase changes of the type of hyper- and hypodynamia in the myocardium is attributed to the anatomo-physiological characteristic features of the cardiovascular system during the puberty period. Parallel to aging, the discrepancy in development between heart and vessels gradually disappears. The relative myocardial hyperfunction, occurring as a compensatory reaction of the organism, loses its significance. The heart begins to work in a regimen of relative hypodynamia.