The postexercise electrocardiogram ∗: Its value in the diagnosis and prognosis of coronary arterial disease

Abstract

The results of long-term clinical follow-up evaluation and postmortem evaluation in a large series of patients, and in a smaller series of normal healthy persons who have had postexercise electrocardiograms, are briefly reviewed and summarized. The postexercise electrocardiogram with an ischemic S-T configuration has been found to be the only reliable electrocardiographic manifestation of coronary insufficiency. It has both diagnostic and prognostic value. The presence of electrocardiographic changes in either the resting or postexercise electrocardiogram should not be considered synonymous with organic coronary arterial disease, especially obstructive coronary atherosclerosis. Such changes have been observed in patients who have normal coronary arteries but in whom metabolic and hemodynamic abnormalities are associated with either severe anemia, electrolyte disorders, drug therapy, pulmonary and systemic hypertensive vascular disease, or obstructive valvular and vascular lesions with a low and fixed cardiac output. However, since obstructive coronary atherosclerosis is by far the most common cause of coronary insufficiency, its presence should be strongly considered as the cause of coronary insufficiency until proved otherwise. Correlation with abnormalities in the coronary arteries of deceased persons who had had postexercise ischemic electrocardiographic changes indicate that, in general, ischemic S-T segment changes occur only when advanced and diffuse occlusive coronary disease is present. This finding is in agreement with physiologic and radiologic correlations as made by others in living patients. Usually people who show such ischemic S-T changes have a poor prognosis and are sensitive to complicating factors, such as thrombosis or hemorrhage into sclerotic placques, which further compromise the coronary circulation. Sudden death or arrhythmic deaths in the early stages of an infarction are common. The interval between the initial finding of ischemic changes and death, however, was quite variable and a positive test result does not indicate a grave prognosis. After 10 years, 40 per cent of the subjects studied were still living. This finding indicates the type of coronary death which might be expected. The degree and severity of S-T depression are not important in diagnosis, but they do reflect to a significant degree the severity of the insufficiency and the prognosis of heart disease. Other postexercise electrocardiographic changes, such as isolated changes in T wave polarity and junctional RS-T depression with adequate precordial tracings, presented poor correlation with subsequent clinical coronary disease or coronary disease at autopsy. These changes are not considered useful in the diagnosis and prognosis of obstructive coronary disease. When coronary atherosclerosis was the only condition found at necropsy, neither lesser degrees of generalized occlusive disease nor complete occlusive lesions in an isolated vessel, either with or without myocardial infarction or fibrosis, was regularly associated with ischemic changes. Therefore, the absence of abnormal changes in a postexercise electrocardiogram does not exclude organic coronary disease. Such a finding may occur with a different type and a lesser degree of coronary disease which has been observed to provide a more favorable prognosis for longevity but not for the eventual development of significant clinical coronary disease.