THE SIGNIFICANCE OF DISPLACEMENT OF THE RS-T SEGMENT

Abstract

By applying pledgets soaked in M/5 KCl soln. to the surface of the heart definite electrocardiographic patterns were produced. When placed on the right ventricle, KCl produced depression of the S-T segment in the 3 conventional leads. Elevation of the S-T segment followed treatment of the surface of the left ventricle. This was interpreted as the result of depolarization of the surface treated, and the removal of its contribution to the normal electrocardiogram, with resulting preponderance of the opposite ventricle. When adjacent surfaces of both ventricles were treated with KCl, leads I and III showed opposite deflections. Elevation of S-T in lead I and depression in lead III characterized anterior lesions, while depression in lead I and elevation in lead III were found with posterior lesions. This indicates that action currents from contiguous areas of the 2 ventricles are not summed in leads I and III.