Shrinkage of the heart in anesthetized, thoracotomized dogs.

Changes in heart size have been studied by means of intra ventricular gages, serial roentgenography and cinefluoiographic angiocardiography. Evidence is presented that the area of the cardiac silhouette and the area and diameter of the left ventricle all diminish in response to thoracotomy and during recovery return toward the pre-operative dimensions. Since fundamental concepts of cardiac function and control are based largely on investigation of exposed hearts, these concepts must be re-examined in intact, unanesthetized animals and man.