Hemodynamic Mechanisms of Reduction of Venous Return and Pulmonary Circulation during Experimental Myocardial Ischemia

Ischemia of left ventricular myocardium in cats moderated blood flow in the venae cavae and decreased venous return, which leads to a drop of blood flow and blood pressure in the pulmonary artery. Shifts in the right atrial pressure had no effects on changes in venous returns. After elevation of the left atrial pressure, promoted by a decrease in contractility of the left ventricular myocardium, blood pressure in the pulmonary artery decreased to a lesser extent than pulmonary blood flow, but did not correlate with shifts in pulmonary vascular resistance.