Ito, and its underlying subunit mRNA and protein expression in control, DHF, and CRT. A, Representative current traces in lateral myocytes from control, DHF, and CRT ventricles elicited by the voltage-clamp protocol shown in inset. B, Peak current-voltage relationship of Ito in each group. C, Ito density at +40 mV in anterior and lateral myocytes of each group. D through G, Kv4.3 and KChIP2 mRNA and protein expression in LV midmyocardial tissue isolated from control, DHF, and CRT dogs. A or ANT indicates anterior; L or LTR, lateral; and CSQ, calsequestrin. †P<0.05 vs control.