Observations on the Atria of the Human Heart by Direct and Semidirect Electrocardiography

Abstract
By evaluation of direct electrocardiographic leads from the right atrium and semidirect esophageal leads from the left atrium, "atriodiagrams" have been constructed for both atria. The spread of activation in the atria has been studied under normal conditions as well as in cases of mitral heart disease, cor pulmonale, etc. In cases of doubtful enlargement of the left atrium, esophageal electrocardiograms may be helpful for diagnosis. In six cases of auricular flutter the results were not uniform.