Left Ventricular Function in Experimental Pulmonary Embolism

Abstract

The hemodynamic effects of acute pulmonary embolism were studied in 13 pentobarbital-anesthetized dogs (19.1 to 27.2Kg). Pulmonary embolism was produced by injections of 1-8ml. of a 33% barium sulfate emulsion into the right ventricle. Observations were made before and 10-15min. after each of several injections. Cardiac output, stroke volume, left ventricular systolic pressure, aortic mean pressure, left ventricular ejection fraction, and left ventricular end-diastolic volume fell following repeated pulmonary embolization. Left ventricular end-diastolic pressure did not change significantly; thus, left ventricular end-diastolic distensi-bility diminished. Peak circumferential-shortening rate of the left ventricle normalized as rate per unit length of circumference remained unchanged in spite of a decrease in developed force. Left ventricular stroke work for any given end-diastolic volume in each animal following pulmonary embolization fell below the regression line for the control state. We conclude that repeated acute pulmonary embolization impairs left ventricular contractility.