Schematics of Markov model for gating and ionic currents of WT hERG1 channels. The model consists of two components, one for voltage sensing with the states S₀ to S₁₄ (A) and the other for activation and inactivation with the states C₀, C₁, O, and I (B). The coupling between the components is via the rate coefficient α_C0,C1, which is a function of the states S₄, S₈, S₁₁, S₁₃, and S₁₄ in the component for voltage sensing.