The Electrocardiogram during Exercise

The electrocardiogram after exercise has proved to be an extremely valuable tool in the diagnosis of coronary artery disease. However, it fails to record the events during the actual period of exercise at the time of the greatest stress on the circulation. Recent technics have enabled us to take the electrocardiogram during the period of exercise. Data presented indicate that the electrocardiogram taken during this period of exercise adds much to the information obtained in the postexercise electrocardiogram; at times, this information may be crucial in determining evidence of abnormalities in the exercise study. The tracings may be solely positive or more markedly positive during the period of exercise. Evidence of such changes would be helpful in diagnosis and in the early termination of the exercise test. It is our belief that the complete electrocardiographic exercise study should include tracings taken both during and after exercise, and the data obtained during both of these periods should be available for evaluation. Although the complete exercise test adds much to the diagnosis of coronary artery disease, the presence of a normal test does not necessarily exclude this state. Evaluation of the tracing taken during exercise is in its infancy. Much still needs to be done relative to (a) more adequate standardization of the type of exercise to suit the individual subject, (b) improvement of standardization of apparatus, (c) standardization of leads and their placement, and (d) more rigid standardization of criteria for normality and abnormality.