Coronarography and bicycle ergometry data in 70 patients with ischaemic heart disease and in 35 patients with the intact cardiac arteries have been compared. In 42 patients with ischaemic heart disease and in 28 healthy individuals the state of intracardiac haemodynamics after exercise have been studied with echocardiography. It was shown that the changes in the total of R (sigma R) waves in multiple leads serve as a sensitive (70%) and specific (88.6%) criterion to detect lesions of the coronary arteries. The increase of sigma R after exercise is, as a rule, combined with marked atherosclerosis, upset contractile function of the myocardium and decreased tolerance to exercise. Uniform decrease of sigma R in multiple leads points to normal or insignificant changes in the function of the left ventricle and is seen in patients with lesion of one vessel or with intact coronaries.