Newborns with congestive heart failure are universally treated with digitalis compounds. The hypothesis tested in these studies is that this drug is deleterious in the setting of ischemia and reperfusion because of Na/k. ATPase inhibition of abnormally low concentrations of this enzyme. Newborn pigs will be treated with digoxin for five days in clinically relevant doses. Treated and non-treated hearts will have intracellular myocardial sodium and calcium concentrations determine. Three groups of 20 hearts each will be placed on an isolated working heart apparatus. Ischemia and reperfusion will be used and contractility functions assessed together with biochemical analyses. Age matched non-treated controls will be used.
