Left Ventricular Residual Volume in the Intact and Denervated Dog Heart

Abstract

Left ventricular volumes were measured at rest and during electrically stimulated muscular exercise in 28 anesthetized dogs. Volumes were calculated from images obtained during biplane cineangiofluorography. Under control resting conditions from 30 to 55% of the diastolic volume of the left ventricle remained after ejection. This residual volume of blood became an immediate source of the increased ventricular output during the beginning of exercise. Following vagectomy, sympathectomy, and total cardiac denervation, the ability to increase cardiac output during exercise persisted, but was accomplished by increased ventricular filling rather than by diminution of the residual volume.