The electrocardiographic patterns of acute myocardial infarctions are a matter of common knowledge, and the serial changes have been documented by a number of authors. Less attention, however, has been directed to the serial changes due to second infarctions, which are the subject of this study. This report is limited to cases in which an original infarction of the anterior type is followed at a later date by a second of the posterior type. REVIEW OF THE LITERATURE On this subject, the earliest pertinent reference we were able to find was that of Levine and Brown1in 1929. They reported a series of 46 cases of coronary thrombosis; 6 of these showed both "old and recent lesions." Of these six, one (case 19) showed an electrocardiographic pattern of the anterior type in 1922 and a posterior type pattern five months later. Four years later, Wood, Bellet, McMillan, and Wolferth