Changes in the presystolic length in the phase of late diastole and in the size of active shortening in the phase of ejection were determined in the ischemic area and in areas of the myocardium bordering upon and in those remote from the focus of ischemia in acute experiments on the 20th and 60th seconds of reversible clamping of the coronary artery. Marked increase in the presystolic length and size of active shortening of the remote areas was noted by the 20th second. In the ischemic zone these values decreased. Due to the effect of a therapeutic dose of inderal, the intensifying reaction of the remote areas diminished markedly and the unfavourable effect of ischemia on the stretching and shortening functions of the ischemic zone became somewhat weaker. Metacin caused no such effect.