[Myocardial contraction and relaxation in a regimen with a physiological loading sequence].

A regimen imitating the intact heart loads revealed independence of the terminal-systolic strength of the trajectory of shortening in the isolated myocardium, the strength being determined by the terminal-systolic length of the preparation, the latter being also the mechanical determinant of velocity of the relaxation isometric phase. The heterometric relaxation portion revealed within the distension phase, depended on the distension velocity, diastolic rigidity and the terminal-systolic length. The experimental possibilities of the regimen are discussed.