Lee and co-workers' revised cardiac risk index was used to study the perioperative cardiac outcome of 296 patients. The index uses a history of ischaemic heart disease, congestive cardiac failure, diabetes treated with insulin, a creatinine greater than 180 micromol/l, cerebrovascular disease and high risk surgery as the risk factors involved in predicting a perioperative cardiac event. It was derived on the basis of data from patients over the age of 50 years undergoing elective, noncardiac surgery with an expected inpatient stay of two or more days. The presence of one, two and three or more risk factors predicted a risk of a major cardiac event of 1.3% (95% confidence interval [CI] 0.7 to 2.1), 3.6% (95% CI 2.1 to 5.6) and 9% (95% CI 5.5 to 13.8) respectively in Lee's derivation group of 2,893 patients. In our audit of 296 patients we observed a cardiac event rate of 0.8% (95% CI 0 to 2.3%), 6.7% (95% CI 1.6 to 10%) and 2% (95% CI 0 to 5.9%), in patients with one, two and three or more risk factors respectively. The more frequent use of ECGs and troponin levels in the routine postoperative care of high risk patients undergoing major noncardiac surgery is recommended on the basis of the frequency of a positive result and the impact of a positive result on a patient's management.