Figure 7. Dependency of E-4031 modulation of APD on repolarization rate.

Effect of I_Kr inhibition (3 μm E-4031) on action potentials with repolarization rates (dV/dt)≤ 1 V s⁻¹ (A) and > 1 V s⁻¹ (B). C, E-4031-induced APD prolongation in cells with dV/dt≤ 1 V s⁻¹ and > 1 V s⁻¹. Action potential duration was modulated by constant current injection during the repolarization phase. Cells were paced at constant cycle length (2 s); I_Ks was blocked (10 μm chromanol 293B) throughout the experiment.