Figure 5. The effects of volatile anesthetics on atrioventricular nodal conduction time. Shown are concentration-dependent effects of halothane, isoflurane, and desflurane on the atrium-to-His bundle interval. Each bar represents a mean +/- SD of seven experiments for the halothane and isoflurane groups and of six experiments for the desflurane group. Significant changes (P < 0.05) are indicated:*control versus 1 or 2 minimum alveolar concentration (MAC) for a given anesthetic;[dagger] halothane or isoflurane versus desflurane at a given MAC;[double dagger] halothane versus isoflurane at a given MAC; and [section] 1 versus 2 MAC for a given anesthetic.