Multiple-Lead Exercise Electrocardiography

A system of multiple-lead exercise electrocardiography has been applied to the study of 107 normal subjects and 67 patients with angina pectoris. The results of this test are compared to those of coronary cinearteriography in 84 patients. In-exercise ECGs gave useful additional information in 59% of the angina patients but were essential for interpretation in 9%. It added considerably to the safety of the test. The value of each individual lead and of the multiple lead system was assessed. Lead V6 was the most often positive, but each made a contribution in some cases. Test-retest reproducibility survey indicated that five of 65 tests on 25 subjects failed to conform. Evidence has been presented that 1.0 mm of ischemic S-T segment shift was the best criterion for a positive test in the subjects studied. The test was positive in 84% of 67 patients with angina pectoris and 3.7% of 107 normal subjects (excluding vasoregulatory hyperreactors). The double two-step test given to the first 41 of the same angina patients for comparison was found to give 61% positive reactions despite the use of multiple leads and in-exercise recording. The test was administered to 84 subjects who were studied concurrently by selective coronary cinearteriograms and these two parameters were compared with the clinical diagnosis of angina in each patient. Since each of these parameters represents a different facet of coronary arterial disease, the agreement among them is very instructive.