Inhalation anesthetics, particularly the halogenated hydrocarbons and cyclopropane, lower the threshold to the arrhythmogenic activity of catecholamines. This intemction is of concern during the resection of a pheochromocytoma when the surgically-induced release of large amounts of norepinephrine and epinephrine from tumors sets the stage for ventricular arrhythmias by a direct effect on the myocardium together with an increase in blood pressure.1Because of the flammability of ether and fluroxene, thearrhythmogenic activity of halo thane,2–1and the potential nephrotoxicity of methoxyflurane,4enflurane has recently been recommended for this operation.5,6In this communication we report our experience with this anesthetic, and in addition, for the first time, cardiac performance has been evaluated by noninvasive techniques during pheochromocytoma resection.