Since the first observations by LaDue and co-workers, in 1954, the serum glutamic-oxalacetic transaminase determination (SGO-T) has become a widely accepted adjuvant for the diagnosis of acute myocardial infarction.1 It is of particular value when the clinical picture or electrocardiogram is atypical. Operative and postoperative cardiovascular crises produce situations that are atypical as a rule. History is usually unobtainable; examination often is difficult; leukocyte count, sedimentation rate, temperature, and other indices are distorted by the surgical procedure. The electrocardiogram is of inestimable value, but it has limitations: Diagnostic electrocardiographic changes may take time to develop; they may be obscured by ventricular arrhythmias or intraventricular block, and subendocardial lesions may cause only nonspecific changes. The clinician is not infrequently faced with the dilemma of an unresponsive, hypotensive patient whose electrocardiogram may show only sinus tachycardia and primary T-wave changes. If the SGO-T determination is to be of value in assessing the