Exercise Electrocardiography as an Estimation of Cardiac Function

More than two score years of experience with the standardized two-step test have confirmed it to be a safe, simple and reliable procedure for aiding in the discovery and evaluation of coronary heart disease and for the evaluation of the adequacy of the coronary circulation on exercise in those with other forms of heart disease. “Ischemic” depression of the RS-T segment is the chief finding of a “positive” response, but “junctional” type depressions may also occur in patients who have compromised coronary artery circulation. A positive test suggests myocardial ischemia, and carries with it increased risk of cardiac morbidity or death, even in asymptomatic persons. A negative response has statistically proven favorable prognosis. The test may be performed in the presence of an abnormal control ECG, provided it is stable and does not represent “impending” myocardial infarction. Monitoring the ECG during exercise is also feasible, but does not appear to increase the overall diagnostic yield. It is worthwhile, however, in the detection of arrhythmias which may appear only in the exercise period. Monitoring techniques, both electronic and “hard-wire,” depend on careful and secure application of electrodes, the most convenient of which are commercially available band-aid types. Various “bipolar” leads or conventional unipolar leads V4, V5, or V6 can now also be recorded.