Effects of desflurane in rat myocardium: comparison with isoflurane and halothane.

Abstract

The cardiovascular effects of desflurane have been investigated in several in vivo animal and human studies. To determine the possible contributions of myocardial depression, the effects of desflurane on various contractile parameters in isolated cardiac papillary muscles were compared with those of isoflurane and halothane. The effects of desflurane, isoflurane, and halothane (0.5-2.5 minimum alveolar concentration [MAC]) were studied in rat left ventricular papillary muscles (29 degrees C; pH 7.40; stimulation frequency, 12 pulses/min). The inotropic effects were compared under low (isotony) and high (isometry) loads, using the maximum unloaded shortening velocity (Vmax) and maximum isometric active force (AF). The lusitropic effects were compared in isotonic and isometric conditions. Desflurane has no significant inotropic effect (AF at 2.5 MAC: 95 +/- 11% of control values; NS) in contrast with halothane and isoflurane (AF at 2.5 MAC: 37 +/- 14 vs. 65 +/- 10%, respectively; P < 0.05). After alpha- and beta-adrenoceptor blockade or pretreatment with reserpine, desflurane induced a negative inotropic effect (AF at 2.5 MAC: 83 +/- 11 vs. 89 +/- 8%, respectively) that was not significantly different from that of isoflurane (AF at 2.5 MAC: 80 +/- 12%). Halothane induced a negative lusitropic effect under low load, which was significantly greater than those of isoflurane and desflurane. In contrast to halothane, isoflurane and desflurane induced no significant lusitropic effect under high load and did not modify postrest potentiation. These results suggest that desflurane did not impair sarcoplasmic reticulum function. When compared with isoflurane, desflurane induced a moderate positive inotropic effect related to intramyocardial catecholamine release. After adrenoceptor blockade, desflurane induced a negative inotropic effect comparable with that induced by isoflurane.