Characteristics of the Atrial APs Used for AP-Clamp and the Corresponding I_HERG in the Presence of Varying K⁺ Channel Blockers to Inhibit I_to, I_Kur or I_CaL.

Ito–: Ito blocked by 500 nM nicotine; IKur.d–: IKur.d blocked by 100 nM 4-AP; ICaL–: ICaL blocked by 10 µM nisodipine; VPeak: the voltage at which IHERG peaks; APDPeak: % repolarization at which IHERG peaks; hence, the value 62% in the table can be expressed as APD62; A: area under IHERG trace, a measure of the volume of K+ passing through HERG channel during an AP; V1/2,IT: voltage for half maximum inactivation calculated from the Boltzmann fit to the instantaneous inactivation curve; k: sloe factor from the Boltzmann fit for instantaneous conductance curve.