1. Methods of retrograde coronary perfusion and direct coronary artery perfusion in combination with a bubble oxygenator were investigated in dogs. 2. Ventricular fibrillation occurred more frequently during the operation
in hypothermia than in the operation performed in combination with the extracorporeal circulation. 3. The optimal pressure of perfusion is considered to be 30 to 35
mm Hg in retroperfusion, whereas, 100 mm Hg in direct coronary artery perfusion. 4. Perfusion by the pressure bottle method is preferable to the gravity method because the fall of blood temperature in the irrigation tubing might cause ventricular fibrillation.
5. From the metabolic study of the methods is clear that there is a tendency to myocardial anoxia after 15 to 20 minutes of perfusion in both methods.</p