Electrocardiographic response to maximal exercise: Treadmill and double master exercise tests in middle-aged Chinese men

Abstract

A prospective study of cardiovascular disease was started in Taiwan in 1965 with the initial emphasis on ischemic heart disease. In the first year of screening examination, 942 middle-aged Chinese men were examined. The multi-stage treadmill test and double Master two-step test were used in addition to the complete clinical history, physical examination and various laboratory tests. Seventy-five (8%) of the 942 patients given the treadmill exercise test showed S-T segment depression of 1 mm. or more after exercise; 89 showed either an S-T segment depression of 0.5 to 0.9 mm. or a respiratory variation of junctional and segmental S-T depressions. The remainder showed S-T segment changes of lesser magnitude. The procedure for the exercise test was modified in the early recovery period to diminish the occurrence of postexercise hypotension in Chinese men. As a result of this modification, the maximal frequency of appearance of postexercise abnormal S-T depression was delayed to four to six minutes after maximal exercise. The prevalence of resting and postexercise T abnormalities was significantly different when persons with abnormal S-T depressions were compared with age-matched controls. Also, the prevalence of a high amplitude R in the left precordial lead differed significantly between the groups with and without abnormal S-T segment depressions ( p < 0.01). QRS axis deviation, exercise arrhythmias and heart rate response did not differ significantly. Exercise S-T segment depression of 1 mm. or more was found in 22 patients subjected to a double Master two-step test. The prevalence of this abnormality was roughly one-third that occurring with treadmill exercise. Exercise arrhythmias and T abnormalities occurred less frequently in the double Master test. The significance of these changes is discussed.