Radioelectrocardiography during Exercise in Patients with Angina Pectoris

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Abstract
The electrocardiographic changes during exercise were examined by means of the radio-electrocardiograph and compared with the changes in the postexercise period in 70 patients with coronary artery disease. This method permitted the recording of one-lead tracings during exercise with a stable baseline and minimal interference. In addition, it has the advantage of permitting free exercise because of the absence of wire connections between the patient and the recording machine. Tracings may be taken on patients performing exercise at a distance of up to several hundred feet from the electrocardiograph. The criteria for abnormality based on double Master two-step tests in 127 normal individuals below the age of 40 years were appearance or increase in ischemic S-T-segment depression of 1 mm. or more, appearance or increase of S-T-segment elevation of 1 mm. or more, inversion of a positive or reversion of a negative T wave, frank inversion of the U wave, widening or narrowing (of a previously widened) QRS complex, and appearance of multiple premature beats. Thirty-seven of the 70 patients (53 per cent) showed electrocardiographic abnormalities during the period of exercise (single Master two-step test), while only 24 (34 per cent) had similar changes in the postexercise period. Twenty-three of the 70 patients had normal resting electrocardiograms. Of these, 11 (48 per cent) had abnormal alterations during, and six (26 per cent) after exercise. Forty-seven of the 70 patients had abnormal resting electrocardiograms. Twenty-six of these (55 per cent) had abnormal changes during exercise and 18 (38 per cent) after exercise. The advantage of recording the electrocardiogram during exercise is shown by the fact that in 17 of the 37 patients with abnormal responses, the changes were limited to the actual period of exercise and the immediate postexercise period, and would probably be missed were the postexercise tracing taken alone. Possible improvements in technic aimed at increasing the incidence of positive responses are discussed. It is suggested that the recording of the electrocardiogram both during and after exercise should replace the presently used technic in the Master two-step test.