In a prospective study we examined the strength of association between preoperative left ventricular performance measured by radionuclide cardiography in patients with cardiac or pulmonary insufficiency (high-risk patients) and cardiopulmonary complications associated with anaesthesia and surgery. Detailed pre-, intra- and postoperative data collected for 7306 anaesthetized patients were included in the study. One hundred and thirty-one patients (1.8%) were classified as high-risk patients, and 95 patients were examined with radionuclide cardiography. The results demonstrated a 58% incidence of cardiovascular complications for high-risk patients when the left ventricular ejection fraction (LVEF) was abnormal (less than 50% or greater than 70%) compared with 12% when LVEF was normal (50-70%). In addition, high-risk patients with left ventricular end-diastolic volume (LVEDV) greater than 140 ml developed cardiovascular complications in 37% of the cases. Patients admitted to major surgery with LVEF less than 50 or greater than 70% were at greater risk than patients with LVEF = 50-70% as demonstrated by a significant increase in the total incidence of cardiopulmonary complications, 70% vs. 17%. It is appropriate to measure LVEF in patients admitted for major surgery who have an increased risk of cardiopulmonary complications as clinically evidenced by heart failure or severe ischaemic heart disease. As the predictive information given by LVEDV was less than that given by LVEF, there are no clinical reasons for measurement of LVEDV.