The clinical value of myocardial scintigraphy with 99mTc-pyrophosphate in conjunction with bicycle ergometry was assessed through the correlation of the latter's results with the clinical course of coronary heart disease over 1 year in 21 patients with first myocardial infarction during its early healing stage and 17 anginal patients without a history of myocardial infarction. The disease ran a stable course at the time of the testing in all the patients; later on, 11 of those developed various complications associated with coronary heart disease, or died. Three scintigraphic recordings were made: prior to, at the peak of, and after the exercise. Thirteen scintigraphic patterns were identified. They are interpreted on the basis of presumed variation in the degree of myocardial damage and blood supply to affected areas under the effect of exercise; a relation is also noted with predicted risk of complications. The method has proved reliable in identifying patients at low risk for complications. Providing indirect evidence of the quality of blood supply to damaged myocardial areas during rationed exercise, it furnishes additional criteria for the assessment of the patients' working capacity.