Fig. 4. Effect of halothane and sevoflurane on maximum stiffness in neonatal versus  adult cardiac muscle. Data are expressed in absolute stiffness (A  and C ), and relative to control values (B  and D ). *Indicates a significant difference between ages (P < 0.05; n = 12 for controls, and n = 6 for all other groups). †Indicates a significant difference between control and halothane groups. ‡Indicates a significant difference between 1 and 2 minimum alveolar concentration (MAC) anesthetic. Note the considerably smaller effect of sevoflurane.