Electrocardiography has been accorded distinction as a valuable diagnostic adjunct, but as yet relatively little attention has been given to its prognostic value. I have been especially interested in the study of abnormal electrocardiograms with special reference to clinical types of heart disease and the significance of these graphic changes with regard to life expectancy. In the analysis of large groups of cases of heart disease one is impressed with the frequent occurrence of certain graphic abnormalities in definite clinical types of cardiopathies. Such cases invariably present unmistakable objective evidence of high grade myocardial disease. I am referring particularly to significant T wave negativity, to aberration of the QRS complex in all derivations of the electrocardiogram, and to the coexistence of these abnormalities. From the standpoint of prognosis, these changes constitute three well defined groups. A very obvious fact that is brought to the attention of those who correlate large