OBSERVATIONS ON THE GENESIS OF THE ELECTRICAL CURRENTS ESTABLISHED BY INJURY TO THE HEART

Abstract

In the first expt. a very small injured area on the dog''s ventricle was produced by pressure, and the electrical changes followed by means of a unipolar lead from this spot. On injury, the spot became negative when the heart was at rest and positive during complete cardiac activation, measured with respect to the potential of uninjured cardiac muscle. These changes disappeared on recovery from the injury. This observation confirmed the recent results of Eyster, Meek, et al. In the 2d expt., a small area of injury was produced by intramyocardial inj. of 95% alc. By means of unipolar leads, the potential changes with time were followed in the injured area and at points on the ventricles at different distances from the center of injury. Changes in the contour of the QRS complex, indicating an alteration in the pattern of impulse spread, occurred in the injured area and later also in other areas outside this region. A depression of the S-T level occurred, which was maximum in the injured region and became smaller out toward the periphery. These changes tended to disappear with time. A coronary type of upright T wave appeared some time after the injury was produced, and was confined to the margin of the injury and a narrow region surrounding it. This T wave tended to disappear with time. An explanation of the results of both types of expt. is offered on the basis of the classical membrane theory.