Studies on the Pathologic Physiology of Pulmonary Hypertension in Mitral Valvular Disease : Part 2. About the Role of the Pulmonary Venous Resistance

In order to clarify the contribution of pulmonary venous system to developing pulmonary hypertension when the left atrial pressure is elevated, simultaneous right and BROCKENBROUGH'S trans-septal left heart catheterization were carried out. Pulmonary venous resistance were increased when left atrial pressure exceeded 18mm Hg, and positive correlation was obtained between pulmonary arteriolar resistance and pulmonary venous resistance. The resistance in pulmonary venous system is in part responsible for development of the passive pulmonary hypertension as well. It is also suggested from the results of administration of noradrenaline during catheterization in mitral stenosis and the infusion of noradrenaline in normal dogs that catecholamine would be a contributory factor to increase in pulmonary venous resistance under the condition of elevated left atrial pressure.