MYOCARDIAL EFFECTS OF DESFLURANE, SEVOFLURANE, ISOFLURANE, AND HALOTHANE ON ISOLATED HUMAN RIGHT ATRIA IN VITRO

Abstract

Introduction. We studied the direct inotropic effects of volatile anesthetics on isolated human right atrial trabeculae in vitro. Methods. With approval of the local medical ethics comittee, human right atrial tissue was obtain from patients scheduled for coronary artery bypass surgery. Fourty human atrial trabeculae were vertically suspended in an oxygenated (95%O2/5%CO2) modified Tyrode's solution (30[degree sign]C, pH 7.40, [Ca++] (0) = 2.0 mM, stimulation frequency 0.5 Hz), and attached to an isometric force transducer (Gould, Cleveland, USA). After 90 min stabilization, equianesthetic concentrations (0.5, 1, 1.5, 2, 2.5 MAC) of desflurane (n=10), sevoflurane (n=10), isoflurane (n=10), and halothane (n=10) were administred by continuous bubbling in the Tyrode's solution. Anesthetic concentration in the gas phase was continuosly measured by an infrared analyzer (Capnomac, Datex, Helsinki, Finland). Mechanical parameters recorded were active isometric force (AF), peak of the positive force derivative vs time (+dF.dt (-1)). Data are mean +/- SD. Results. Desflurane, sevoflurane, and isolfurane induced a comparable dose dependant negative inotropic effect (Figure 1). Halothane induced a significantly greater negative inotropic effect than that induced by desflurane, sevoflurane, or isoflurane (Figure 1).Figure 1: Effects of desflurane, sevoflurane, isoflurane, and halothane on isometric force (AF, left panel) and the peak of the positive force derivative vs time (+dF.dt (-1), right panel).Discussion. In isolated human right atrial trabeculae, desflurane, sevoflurane, isoflurane, and halothane induced a dose dependant negative inotropic effect comparable to that observed previously in vitro, in rat left ventricular myocardium [1].