[Mechanical tension in different parts of the left ventricle of the heart exposed to inotropic factors]. / Mekhanicheskoe napriazhenie v razlichnykh otdelakh levogo zheludochka serdtsa pri deistvii inotropnykh faktorov.

A study was made of the effects of different inotropic factors on mechanical tension in the left ventricular wall and in the apex of the heart and of the participation of these regions in the formation of hemodynamic characteristics. Adrenaline caused similar effects whereas CaCl2 exerted different inotropic effects on the left ventricular wall and the apex of the heart. Changes in mechanical tension of the wall correlated with variations in the pressure inside the left ventricle. Tension in the apex of the heart produced alterations in the stroke volume.

[Long-term antiorthostasis (-90 degrees) of animals as a model of critical disorders of homeostasis]. / Prolongirovannyi antiortostaz (-90 gradusov) zhivotnykh kak model' kriticheskikh narushenii gomeostaza.

The cardiovascular effect of head-down tilt (at an angle of -90 degrees) was investigated in 25 mongrel dogs exposed to general anesthesia, myorelaxation or pulmonary ventilation. Changes in the circulation and contractility parameters can be subdivided into three periods. At early stages of the exposure an increase in contractile function and hemodynamic changes typical of preload were seen. At later stages progressive disorders of systemic and regional hemodynamics, inhibition of contractile function, and increasing metabolic changes were observed. All this resulted in the death of the animals after 12-20 hours of head-down tilt. Gross structural changes that occasionally were irreversible were detected in organs of the dead animals.