[Compensatory-adaptive changes in the endocardium in functional overload of the heart]

In experiments on 46 dogs a structural rearrangement of the endocardium of the left atrium in the process of development of the chronic compensated cardial insufficiency was studied. Dynamics of changes, caused by hypertrophy of the subendothelial layer of the endocardium and its subsequent differentiation, which led to hyperelastosis of the endocardium, as well as hypertrophy and hyperplasia of the smooth-muscle elements of the endocardium were revealed. Analysis of the data obtained, from the functional point of view, enabled the authors to consider the described rearrangement of the endocardium as one of the mechanisms of cardiac compensation.