Left ventricular angiograms of 60 patients with ischaemic heart disease and 10 normal subjects were digitized frame by frame in order to study abnormalities of wall movement during the period of isovolumic relaxation. Plots were made of regional wall movement around the cavity throughout the cardiac cycle. In normal subjects 1-5 to 3-0 mm of symmetrical outward wall movement occurred during isovolumic relaxation, associated with an apparent increase of left ventricular volume of 10 +/- 4 per cent. The corresponding peak velocities of wall movement were 4-3 to 5-7 cm/s, significantly less than those recorded in the same region of the cavity after mitral valve opening. In patients with ischaemic heart disease, the following abnormalities were encountered: (1) Abnormal inward movement, which, in single coronary artery disease, occurred in the area supplied by the affected vessel. (2) Abnormal outward movement of more than 6 mm in non-affected areas which appeared to be a compensatory phenomenon. (3) An abnormal cavity shape change towards a more circular configuration before mitral valve opening. (4) Reduced peak rates of wall movement in affected areas during systole and filling. It is concluded that such inward wall movement during isovolumic relaxation is abnormal and a sign of local ischaemia whose presence has significant effects on overall left ventricular function in both systole and diastole.