Abstract
A laboratory study designed to investigate the independent pump-like function of the right ventricle of the dog heart is presented. Systolic and diastolic pulmonary arterial pressure fluctuations were used as the definitive criterion for pumping efficiency. Control pressure levels are compared with those recorded after complete damage, by electrosurgical coagulation, of the free right ventricular myocardium. The degree of damage so produced was ascertained from an analysis of electrocardiographic, physiologic and histologic observations. The results are discussed and explained in terms of a postulated mechanism based upon the architecture of the individual ventricular muscle bands.