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(Circulation. 1968;38:691.)
© 1968 American Heart Association, Inc.

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Computer Quantitation of the ST-Segment Response during Maximal Treadmill Exercise

Clinical Correlation

PAUL L. MCHENRY USAF, MC¹; DARWELL E. STOWE B.S.¹; MALCOLM C. LANCASTER USAF, MC¹

¹ From the Internal Medicine Branch, Clinical Sciences and Biometrics Divisions, USAF School of Aerospace Medicine, Brooks Air Force Base, Texas.

The ST-segment response during maximal treadmill exercise was quantitated by digital computer after excessive noise in the electrocardiographic data was reduced by computer averaging. Both the slope and the depression were quantitated.

Two groups of subjects were studied. Group A consisted of 35 subjects between 33 and 57 years of age with confirmed or suspected coronary artery disease. Group N consisted of 73 clinically normal subjects between 24 and 52 years of age. The responses of the group A subjects and the 26 subjects over age 35 in group N were compared by graphically plotting their ST slope and depression values from the last minute of exercise. A linear discriminant analysis computed from these values resulted in a line of separation between the majority of subjects in each of these two groups. This separation was accomplished even though the majority of subjects in group A did not demonstrate segmental ST depression.

Key Words: Coronary artery disease • Quantitation of ST slope and depression • ST-segment abnormalities during exercise • Computer averaging • Maximal exercise stress testing