1 Departments of Pediatrics and Pharmacology, and the Beaumont-May Institute of Neurology, Washington University School of Medicine, Saint Louis, Missouri
The effect of extracorporeal circulation upon the radioactivity from tritium-labeled digoxin and/or its metabolites in heart muscle and other tissues of patients who underwent open heart surgery with the aid of extracorporeal circulation was studied. These experiments demonstrate that the digoxin concentration of the heart muscle was not significantly altered by extracorporeal circulation as measured by the radioactivity in the heart tissue and that no significant radioactivity was detected in the blood from the heart-lung pump. It should be emphasized that patients who are digitalized preoperatively and who undergo open heart surgery with the aid of extracorporeal circulation still have an appreciable amount of the digoxin in the myocardium and other tissues after cardiopulmonary by-pass. Since the concentration of digoxin in heart muscle which would produce maximal cardiotonic effect is not known, the postoperative administration of digoxin and other cardiac glycosides must be approached with caution.
Submitted on December 8, 1962