Figure 5. Effect of a HERG channel mutation probed with dynamic action potential clamp.

The native delayed rectifier potassium current (I_Kr) of an isolated rabbit left ventricular myocyte was blocked by E-4031 and replaced with either wild-type or R56Q mutant HERG current expressed in a HEK-293 cell using the dynamic clamp technique of Fig. 2C (Berecki et al. 2005). A, superimposed action potentials of the isolated myocyte, which was paced at 1 Hz. B, associated HERG current.