Exercise graded by heart rate in electrocardiographic testing for angina pectoris.

ATYPICAL features of location, quality, time course, radiation, precipitating and ameliorating factors of angina pectoris evoke in the clinician a desire for objective evidence to aid in this sometimes difficult diagnosis. Interest in the electrocardiographic response to exercise of subjects with and without angina pectoris is a manifestation of this difficulty. The "two-step" test, introduced by Master and Jaffe in 1941,1 is by far the most widely used procedure of this type, but other investigators prefer an unstandardized test,2' 3 allowing the patient to exercise at his accustomed rate until dyspnea, fatigue, or pain develops. Of greater importance than the mode of exercise is, in our opinion, the reproduction in every subject of a standardized degree of cardiac stress regardless of age or work capacity of the individual undergoing the procedure.