Blood flow in intact and constricted coronary arteries under the influence of ouabain

The effects of ouabain on intact and experimentally constricted coronary arteries were investigated in anaesthetized, thoracotomized dogs. Ouabain decreased the blood flow in the intact artery without changing the flow per beat values and increased flow in the constricted artery. Since ouabain decreased left ventricular enddiastolic pressure, it is proposed that the drug-induced augmentation of flow in the constricted artery is related to an elevation of driving pressure to the endocardial layers of the myocardium which are supplied by the constricted artery.