Radiographic Visualization of Lymphatic Drainage of Heart Muscle and Pericardial Sac in the Dog

¹ Cardiovascular Institute, the Division of Cardiovascular Disease, and the Department of Diagnostic Roentgenology, Michael Reese Hospital and Medical Center, Chicago

The present study was done to determine whether radiopaque material instilled into the pericardial sac in the dog would be removed via lymphatics, thereby allowing radiologic visualization of the lymphatic system. In addition, we wished to determine whether the mediastinal lymphatic system draining the pericardial space was the same as that draining the ventricular myocardium. Micropulverized barium sulfate injected into the pericardial space and into the heart muscle in the dog gave radiographic visualization of the mediastinal lymphatic system draining these areas. These studies show that the lymphatic drainage route is essentially the same from the pericardial sac and the myocardium, though a retrosternal node was often seen after the barium was injected into the pericardial space which was not seen after the heart muscle injection. Furthermore, the results suggest that the lymphatic drainage from the pericardial space is probably primarily via subepicardial lymphatics, rather than from the parietal pericardium. Such observations may prove to be important to the understanding of the dynamics of pericardial effusions.