THE EFFECT OF VARIOUS ANESTHETICS AND CERTAIN DRUGS ON THE ELECTROCARDIOGRAM OF THE DOG

¹ Fellow in Anesthesia, The Mayo Foundation, Rochester, Minnesota

The electrocardiographic changes in the dog during anesthesia with ether, cyclopropane, sodium amytal and pentothal sodium were studied after a control series of 219 electrocardiograms had been taken on four dogs over a period of three months. The only attempt to control the position of the heart was by placing the animal in exactly the same position for each experiment. Ether caused negative T waves to become positive in leads I, II and III, but there was little change in lead IV. Cyclopropane caused negative T waves to become positive in leads II and III and caused a marked deepening of the T wave in lead IV. Sodium amytal and pentothal sodium caused no changes of significance. Arrhythmias occurred most frequently with ether and cyclopropane anesthesia. The modifications were of a transient nature. The physiologic mechanism remains unexplained.