REVEALING RISK-FACTORS FOR HEMODYNAMIC DI SADAPTATION DURING EXERCISEAS EVIDENCED BY GENETIC-STUDIES .2.

Examination in 28 pairs of twins who were studied by echocardiography just after their performance of exercise (Stage I) and at the peak of effects produced by oral anapriline (Stage II) have shown that at rest such parameters as end-systolic volume, ejection fraction, relative c hanges in the internal dimension of the left ventricular cavity during a cardiac cycle, show moderate-to-high genetic predisposition. At the same time, a persistent contribution of hereditivity to myocardial co ntractility is found only for end-systolic volume when the conditions of the examination were changed. The lesser extent to which contractil ity parameters had hereditable signs, the more intensively they varied under different conditions. It is assumed that the contraction rate o f circulatory myocardial fibers is less resistant to environmental fac tors. A significant decrease in this parameter during anapriline admin istration allows one to suppose that cardiac decompensation in patient s with coronary heart disease starts with damages to the very myocardi al circulatory muscles.