[Topography of the contours of the inner surface of the wall of the left ventricle of the heart in systole].

Chosen at random 38 diastolic preparations of human hearts from persons having not any cardiac pathology, as demonstrate the postmortem examination, have been investigated. The left ventricle casts have been made during the first 24 hours after death according to a strictly fixed technique by means of filling the cardiac chambers with polymere mass--protacryl--under a physiological pressure of the diastolic filling. The trabecules are arranged as a spiral from the apex of the ventricle up to the atrioventricular fibrous ring, with approaching the apex the spiral step increases and the trabecules straighten.

[Autovibration of a circular locking element of the aortic valve prosthesis].

Some experimental results when studying self-sustained vibrations of the ball locking element for an artificial heart valve are presented. The sign-changing dependence of a ball drag coefficient upon the ball stroke has been shown to cause these vibrations. Undamped oscillations result in a considerable growth of the valve hydrodynamic resistance.

[Relief of the internal surface of the left-ventricular wall at different phases of cardiac activity and its functional role].

The work has investigated 33 preparations of the heart taken at random from people who died not of a heart pathology. The heart chambers were filled with protacryl . It was shown that when changing from systole to diastole a rotating clockwise movement of ventricle walls took place round its long axis.

[Flow past an artificial heart valve with a lens-shaped shutoff element].

An axisymmetric stream-line steady flow of perfect noncompressible liquid through the artificial heart valve with the lens-shaped shut-off element is considered. The liquid motion is described by a continuity equation for which the Dirichlet's problem in the plane of the valve meridional section is stated. Written in the finite differences the differential equation is solved by using a digital computer (ZDBM-220).