[Study of hemodynamic effects of the methoxamine in 8 cases of obstructive cardiomyopathy with mitral valve insufficiency].

The haemodynamic effects of intravenous Methoxamine were studied in 8 patients with hypertrophic obstructive cardiomyopathy (HOCM) with mitral incompetence (group I) and 8 patients with mitral incompetence due to valvular, subvalvular or other causes (group II). In both groups the left ventricular end-diastolic pressure rose significantly without any great change in the end diastolic surface area: the ventricular distensibility is reduced in both cases. The mean capillary pressure, the V wave/mean capillary pressure ratio, and the degree of regurgitation of the two groups changed in opposite ways : in mitral incompetence due to varying causes (group II) the regurgitation increased, but in mitral incompetence due to HOCM (group I), it decreased. The left ventricular intracavitary gradient in HOCM tended to disappear under the effect of Methoxamine as the systolic aortic pressure approached the basal values recorded in the apical area.