Figure 2.

A schematic of the experimental procedure showing the sequence of voltage-clamp protocols used. A total of nine voltage-clamp protocols were used, and each of them was performed four times: twice before E-4031 addition and twice after to ensure stability and reliability of the recordings. Only the staircase protocol (green, 15 s) was used for fitting (or calibrating) the mathematical model. All of the other eight protocols (blue) were used for validation only. White sections indicate a nonmeasurement region, where cells were held at −80 mV to allow the cells to settle to steady state between protocols (>5 s) or were continuously stimulated by the hERG screening protocol to allow the drug to wash in (>5 min). For details of the protocols, please refer to Supporting Materials and Methods, Section S1. To see this figure in color, go online.