[Effect of a decrease in viscosity on myocardial blood flow and function in myocardial infarct]

In 5 dogs the effect of a decrease in blood viscosity on myocardial blood flow (radioactive microspheres) and left ventricular function (Sarnoff curves) following ligation of the left anterior descending coronary artery was tested. Moderate anaemia produced a significant increase in coronary blood flow to the total left ventricle (+ 100%) and to the ischemic area (+ 400%). Depressed left ventricular function after coronary ligation alone was restored when blood viscosity was lowered only slightly. Severe anaemia further increased coronary blood flow but left ventricular function worsened.