Compliance of the apex of the left ventricle in unanesthetized dogs

¹ Cardiac Research Laboratory, Cincinnati General Hospital, and Department of Medicine, University of Cincinnati, Cincinnati, Ohio

A method has been developed for determining the compliance of the left ventricle of the unanesthetized dog through the chronic sealing of an oncometer to the cardiac apex. The volume of the enclosed apex could be increased by a known amount and the end-diastolic transmural pressure measured. The heart rates of the unanesthetized dogs were slow and the volume of the apex was held constant, hence rate-dependent nonelastic factors were minimized. It is concluded that under the conditions of these experiments, end-diastolic compliance either decreased during infusions of l-epinephrine and angiotensin or did not change. Acetylstrophanthidin administration had no effect on ventricular compliance.

Submitted on June 8, 1964