The present study summarized the results of QTc. in 54 subjects, 8 of which were patients with coronary heart disease and 46 normal.The exercise tests were carried out on an ergometric bicycle with a submaximal exercise andQT interval was corrected for heart rate according to Bazett's formula (QTc=QT/R-R-). All patients were subjects to resting ECG before the test, during excerxise, and immediately fol owing the end of the exercise. Electrode jelly contact disk electrodes were used for the CMS. Results showed that coronary heart disease patients all had a prolongation of the QTc following exercise with variations of 0.06+0.02s The QTc of all normal subjects, except one, Showed a shortening or no ohange.Our study thus reveaded that the finding of QTc variations with exercise all of value for the diagnosis of coronary heart disease.