Left Ventricular Volume Studies in Tranquilized Dogs with Local Anesthesia

Left ventricular volumes were estimated by thermodilution in unanesthetized dogs given the tranquilizer, perphenazine. During systole, the left ventricle emptied an average of 40% of its end-diastolic volume. This is a significantly greater proportion than observed previously during general anesthesia with several different agents. Left ventricular mid-systolic wall force was calculated. Higher force values at a given end-diastolic volume occurred during intravenous infusion of norepinephrine. Methoxamine failed to change these relationships.