Quantitation of QRS and ST segment responses to exercise

Journal/Book: Reprinted (from American Heart Journal St. Louis Vol. 71 No. 4 Pages 455-466 April 1966. 1966;

Abstract: Robert A. Bruce M.D.; John A. Mazzarella M.D.*; John W. Jordan Jr. M.D.; Elmer Green E.E.; Seattle Wash. From the Division of Cardiology Department of Medicine University of Washington Seattle Wash. These studies have been supported by Grants CD-00066-03 and CD-00150-01 from the United States Public Health Service Chronic Disease Division and Grant HT 5022 from the National Heart Institute National Institutes of Health United States Public Health Service. Received for publication June 10 1965. *Medical Officer Heart Disease Control Program United States Public Health Service. Summary 1. A new method is described for dual track magnetic-tape recording of the exercise electrocardiogram and quantitative analysis of successive voltages of 100-beat samples at each workload by means of a computer of average transients. This minimizes respiratory and other distortions and facilitates objective appraisal of responses. 2. Optimal loci with respect to inherent variability both at rest and during maximal physical exertion of middle-aged "healthy" men were defined for the PQ reference voltage segment and for parts of the ST segment. 3. The entire group of 57 clinically normal men exhibited progressively more depression - of the ST segment with increasing workloads and considerable restitution within 3 minutes of recovery from maximum exertion. Even greater ST segment changes were observed in 9 of these men whose postexercise ST responses were visually classified as abnormal prior to automated quantitative analysis. 4. Ventricular conduction time was shortened only in normal subjects; changes in QRS forces were also detected. 5. It is concluded that more quantitative and objective appraisal of ECG responses to exercise is feasible for further studies of the pathophysiology of the ischemic responses as well as epidemiological surveys for detection of individuals with increased risk for subsequent clinical manifestations of coronary heart disease. schö

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