Electrocardiographic Studies on Artificially Produced Pulmonary Artery Occlusion in Human Beings

The clinical differentiation between pulmonary artery occlusion and coronary artery occlusion is difficult, and at times impossible. In the past this was a matter purely of academic interest, since treatment of both consisted of complete rest and supportive care. Now, however, when the application of specific therapy is possible, early accurate diagnosis becomes imperative. The electrocardiograph is a physical apparatus which accurately records the curves of differences in electropotential generated by the functioning heart. With any appreciable obstruction to pulmonary artery circulation (as that produced by an embolus) there is a rise in the pulmonary artery pressure gradient, and therefore increased resistance is presented to the discharge of blood from the right ventricle. On this basis, it is, a priori, to be suspected that there would be a disturbance in the electropotential balance which would be reflected on the electrocardiogram. McGinn and White (1935)1coined the term acute cor