Serial pressure-volume studies in the excised canine heart

Abstract

Serial left ventricular pressure-volume curves were obtained on excised canine hearts maintained at different constant temperatures. The technique employed permitted detection of slight changes in distensibility of the ventricular wall and in shortening of muscle fibers. The results demonstrated that the ventricular distensibility and fiber length at 36°C were unaffected until approximately 80 minutes after excision, beyond which time they decreased rapidly at a constant rate. Hypothermia prolonged the onset and rate of these changes and, at 5°C, changes did not occur until after 5 hours. Sodium fluoride, injected into the left coronary artery in order to block glycolysis, induced early and rapid changes in distensibility and fiber length.