In vitro effects of desflurane, sevoflurane, isoflurane, and halothane in isolated human right atria

Background: Direct myocardial effects of volatile anesthetics have been stu died in various animal species in vitro. This study evaluated the effects o f equianesthetic concentrations of desflurane, sevoflurane, isoflurane, and halothane on contractile parameters of isolated human atria in vitro. Methods: Human right atrial trabeculae, obtained from patients undergoing c oronary bypass surgery, were studied in an oxygenated (95% O-2-5% CO2) Tyro de's modified solution ([Ca2+](o) = 2.0 mM, 30 degrees C, stimulation frequ ency 0.5 Hz). The effects of equianesthetic concentrations (0.5, 1, 1.5, 2, and 2.5 minimum alveolar concentration [MAC]) of desflurane, sevoflurane, isoflurane, and halothane on inotropic and lusitropic parameters of isometr ic twitches were measured. Results: Isoflurane, sevoflurane, and desflurane induced a moderate concent ration-dependent decrease in active isometric force, which was significantl y lower than that induced by halothane. In the presence of adrenoceptor blo ckade, the desflurane-induced decrease in peak of the positive force deriva tive and time to peak force became comparable to those induced by isofluran e. Halothane induced a concentration-dependent decrease in time to half-rel axation and a contraction-relaxation coupling parameter significantly great er than those induced by isoflurane, sevoflurane and desflurane. Conclusions: in isolated human atrial myocardium, desflurane, sevoflurane, and isoflurane induced a moderate concentration-dependent negative inotropi c effect. The effect of desflurane on time to peak force and peak of the po sitive force derivative could be related to intramyocardial catecholamine r elease. At clinically relevant concentrations, desflurane, sevoflurane, and isoflurane did not modify isometric relaxation.