[Study of left ventricular function in chronic volume overload (author's transl)].

51 patients with aortic incompetency (AI), 46 with mitral insufficiency (MI) and 31 with congestive cardiomyopathy (CM) have been studied as examples of primitive myocardial lesions. The mean parameters calculated were: the left ventricular end-diastolic pressure (LVEDP), the ventricular volumes, the ejection fraction (EF), the end-systolic pressure-volume ratio (Emax) and the eccentricity. In the chronic volume overload, the relationship between the pump performance and the contractility (EF-Emax) is parabolic with an initial plateau (myocardial failure without circulatory failure); the EF-Emax relationship, in the CM, is linear without a plateau. The LVEDP is a limiting factor of the pump-contractility relationship in the AI; for the same value of the contractility, the pump function is greater depressed if the LVEDP is 25 mmHg (loss of the preload modulation); in the MI and CM, the depression of the pump performance is a function only of the depressed contractility. The end-systolic eccentricity is correlated with Emax; the changes in the geometrical shape of the left ventriculr chamber is due to the depressed contractility.