Factors Which Initiate or Influence Edema in the Isolated Dog's Heart

Abstract

Isolated dog hearts were perfused while time heart weight was electrically recorded. Arterialized blood was pumped into a coronary perfusion reservoir either from the femoral artery of a donor dog or from the arterial outlet of various oxygenators. The right heart was widely open. The presence of myocardial edema and the rate of fluid accumulation in heart muscle were observed from the slopes of tile weight registration and from the difference of the directly measured heart weights before and after an experiment. Blood hold-up was measured in three experiments with tagged red cells: it accounted for 15 per cent or less of the observed weight gain. When the heart was perfused from a donor dog and was not otherwise injured, myocardial edema fluid did not accumulate unless the coronary pressure exceeded 200 mm. Hg. Myocardial edema also formed when blood was diluted with Ringer's solution or after cardiac injury; the rate of edema formation was then dependent on the coronary perfusion pressure. Edematous hearts could often be made to lose weight (i.e., edema fluid) when perfused at pressures below 100 mm.Hg. Perfusion with blood from a disposable bag oxygenator initiated inyocardial edema formation almost immediately.