BACKGROUND: Desflurane has some cardiovascular effects similar to isofl-urane. Desflurane has decreased systemic vascular resistance and demonstrated a myocardial depressant property in vivo animal stulies. The purpose of this study was to compare the myocardial and coronary effects of desflurane and isoflurane. METHODS: Cardiac effects were examinated in 24 rat hearts perfused with modified Krebs solution containing 1 MAC and 2 MAC desflurane or isoflurane for 10 min. at each concentration in a retrograde manner. Left ventricle pressure, heart rate and rate of change of ventricular pressure (dp/dt) were mea-sured, as were coronary flow and partial oxygen pressure. Oxygen delivery, myocardial oxygen consumption and percent oxygen extraction were calculated by each measurement. RESULTS: Heart rate, left ventricle pressure and dp/dt decreased each anesthetic similarly in a concentration-dependent manner. Heart rate decreased by 243.86 15.7 beats/min at 1 MAC and 219.14 15.8 beats/min at 2 MAC with isoflurane (control: 262.99 2.35 beats/min.) and by 250 23 beats/min at 1 MAC and 223.89 23 beats/min at 2MAC with desflurane (control 266.94 22.30 beats/min). Coronary flow increased by 13.72 0.99 ml/g/min at 1 MAC and 14.30 1.05 ml/g/min at 2 MAC with isoflurane (control :12.04 0.84 ml/g/min) and by 12.80 1.63 ml/g/min at 1 MAC and 13.71 1.46 ml/g/min at 2 MAC with desflurane (control 14.04 1.22 ml/g/min). Oxygen delivery increased proportionally with coronary flow. The increase in MVO2 was accompanied by a decrease in heart rate and pressure but there were no significant differences. Percent oxygen extraction decreased in a concentration dependent manner. CONCLUSIONS: This study shows that desflurane and isoflurane decreased heart rate, myocardial depression and coronary vasodilating effects, resulting in improved oxygen perfusion effects.