Cardiac function during perfusion of the circumflex coronary artery, with venous blood, low-molecular dextran, or Tyrode solution

Abstract

1. 1. Perfusions of venous blood for 60 minutes at a rate of 25 ml. per minute into the circumflex coronary artery did not alter significantly the rate of heartbeat nor the aortic or venous pressure. Perfusion of low-molecular-weight dextran after perfusion of venous blood at the same rates had similar effects as long as decompensating exsanguination was not performed. 2. 2. Perfusion of low-molecular dextran or Tyrode solution at low rates resulted in fibrillation within 20 minutes. After defibrillation a gradual increase in the perfusion rate to 25 ml. per minute could maintain the normal heartbeat and systemic pressures. 3. 3. When the starting rates of perfusion began at a high level, fibrillation occurred, especially when either low-molecular dextran or Tyrode solution was perfused. In no instance did fibrillation occur when the perfusions were started at lower rates and then gradually increased to 25 ml. per minute within 2 minutes. 4. 4. When, during fibrillation after perfusion of dextran, the perfusion was continued, heart edema occurred. Defibrillation was possible when the perfusion was stopped. 5. 5. After the coronary perfusion with dextran or Tyrode solution was stopped, a steady correlation was observed between the time of establishment of the back pressure, the viscosity of the perfused fluid, and the initial level of postocclusive back pressure. 6. 6. Perfusion of isotonic glucose solution at the same rates resulted in fibrillation. After defibrillation, perfusion of low-molecular dextran could maintain heartbeat and pressures. After re-perfusion of glucose, fibrillation reappeared.