Experimental Study of Coronary Circulation by Coronary Artery Catheterization : (3) Direct Effect of Noradrenalin on Coronary Circulation and Electrocardiographic Changes

Abstract

It has been said that nor-adrenalin exerts a vaso-dilator action on coronary vessels. There are a few investigators, however, who claim a vaso-constrictor action of the drug on coronary vessels. The author, as in part II, examined the action of nor-adrenalin on the coronary circulation following a direct infusion of the drug into the left coronary artery by the coronary catheterization in anesthetized, closed-chest dogs. Electrocardiographic changes caused by the infusion of nor-adrenalin were also studied. Method In addition to the experimental method described in part I, the left coronary was also perfused from a donor dog's femoral artery at a constant blood pressure. The experiments were performed 11 times on 5 adult dogs. Leads CψD and CψS were mostly used in taking electrocardiograms. Results (1) Experiments with coronary artery perfusion from the dog's own femoral artery (a) With 0.013 mg. of nor-adrenalin coronary blood flow increased. Both coronary wedge pressure and femoral arterial pressure also showed a rise. (b) Infusion of 0.13mg. of nor-adrenalin caused an increase in coronary blood flow, and a rise both in the coronary wedge pressure and the femoral arterial pressure. (c) With 0.33mg. of nor-adrenalin coronary blood flow markedly increased. Both coronary wedge pressure and femoral arterial pressure were elevated. (d) When 0.13mg. of nor-adrenalin were infused after the atropinization, coronary blood flow increased, and both coronary wedge pressure and femoral arterial pressure rose markedly. Single use of atropine caused changes neither in the coronary blood flow nor in the blood pressure. (2) Experiments with coronary artery perfusion from a donor dog's femoral artery under constant blood pressure. (a) With 0.013mg. of nor-adrenalin coronary blood flow decreased, while coronary wedge pressure and femoral arterial pressure showed an elevation. (b) With 0.13mg. of nor-adrenalin coronary blood flow decreased, while coronary wedge pressure and femoral arterial pressure became elevated. (c) With 0.33mg. of nor-adrenalin coronary blood flow decreased, while coronary wedge pressure and femoral arterial pressure became markedly elevated. (d) When 0.13mg. of nor-adrenalin were infused after the atropinization, coronary blood flow decreased, and coronary wedge pressure and femoral arterial pressure became markedly elevated. Conclusions (1) Nor-adrenalin exerts a vaso-constrictor action on the coronary artery as adrenalin does. (2) Action of nor-adrenalin on the coronary vessels were strengthened with a previous administration of atropine. (3) The electrocardiogram showed a decrease in pulse rate, an elevation of the T wave, occasional occurrence of right bundle branch block or WPW syndrome. With a previous administration of atropine the electrocardiogram presented changes similar to those in the case of adrenalin infusion.