Figure 6. Dependency of E-4031-sensitive current (I_Kr) on the rate of repolarization.

A, I_E-4031 recorded, by applying the voltage protocol shown in the inset, during ramps of variable steepness (dV/dt). B, model simulation of the experiment of A. C, peak I_E-4031 magnitude recorded from 9 cells as a function of ramp dV/dt (•); in order to eliminate differences between cells, I_E-4031 magnitude is expressed as the percentage of the value observed at dV/dt = 1.5 V s⁻¹, which was measured in all cells. The continuous line represents the relationship independently predicted by the model. D, effect of changes in the time constant of inactivation (τ) on the predicted relation between I_Kr amplitude and dV/dt (data expressed as C.