The effects of propofol (emulsion formulation) on cardiovascular dynamics, myocardial blood flow and myocardial metabolism were studied in 12 patients scheduled for elective coronary artery bypass surgery. Measurements were performed with the patient awake, during steady-state maintenance anaesthesia with propofol 200 micrograms kg-1 min-1 at rest, and during sternotomy when the propofol was supplemented with fentanyl 10 micrograms kg-1. Propofol alone decreased mean arterial pressure and cardiac index; heart rate was increased. Myocardial blood flow and myocardial oxygen consumption were decreased by 26% and 31%, respectively. Myocardial lactate production was seen in one patient during this period. Surgical stimulation, under propofol-fentanyl anaesthesia, led to the return of arterial pressure and heart rate towards baseline; cardiac index decreased further. Myocardial blood flow and oxygen consumption increased such that they almost achieved their baseline values. Myocardial lactate production was seen in one patient. These results suggest that propofol may on occasions, lead to myocardial ischaemia in patients with coronary artery disease, but that it is able to block the sympathetic responses to surgical stimulation when combined with a suitable analgesic.