[The relationship between left ventricular end-systolic pressure and volume. Comparative study of changes in load and inotropism].

This work consists of a comparison of the indices of left ventricular performance measured during the isovolumic nad/or ejection period under changes in load and inotropism, and of the findings on measuring the pressure/volume ratio of the left ventricle. The indices of performance of the left ventricle. The indices of performance of the left ventricle during the ejection phase (ejection fraction, mean speed of fibre shortening, mean standardised speed of systolic ejection) and the ratio pressure/volume were listed for 36 patients, 21 of them before and after perfusion with nitroprussiate, in 6 before and after perfusion of angiotensine, and in 9 from the group before and after post-extra-systolic potentialisation. The indices of left ventricular performance during the isovolumic (formula see text) were measured in 24 of these patients, 15 of them before and after nitroprussiate, and 9 before and after post-extra-systolic potentialisation. These results show that the level of the pressure/volume ratio at the moment of end-systole is independent of the conditions of load--to a greater extent than any other index measured during the isovolumic period or ejectional period--and appears to be thoroughly related to the changes of inotropism.