Exercise Tests in the Diagnosis of Coronary Heart Disease

Abstract

If the resting ecg is within normal limits the best way of testing the patency of the coronary arteries is to subject the patient to factors which increase the work and oxygen consumption of the heart to a constant percentage of the resting value, and determine whether or not this leads to ecg signs of coronary insufficiency. This can be accomplished best by the standardized two-step exercise test introduced by Master. Several modifications of the test are suggested which could make the results of this test even more predictable. Methods of ecg evaluation are described which allow a better differentiation between changes of the S-T segment and T wave caused by tachycardia, heart position and hyperventilation from those caused by coronary insufficiency. The peculiarities of the ecg response to exercise in the presence of ventricular hypertrophy, intraventricular conduction disturbances and myocardial infarction scars are discussed in detail, as well as the factors which may prevent true coronary insufficiency from affecting the ecg in the typical manner.