[Left heart catheterization].

IN patients with mitral valvular disease, right heart catheterization is often performed in evaluating whether or not an operation is indicated. Measurements of pulmonary arterial pressure are made during rest and exercise. The "pulmonary capillary" pressure, which is approximately the same as the pressure in the left atrium, is also measured. In many instances the form of the "pulmonary capillary" pressure curve is identical with the left atrial pressure curve. In some cases, however, the two curves show a different form. As the obstruction to blood flow is between the aorta, the left ventricle and the left atrium. More direct and significant data are then obtained for evaluation of mitral and aortic valvular disease.