FIGURE 1.

Simulated behaviors of APs (EADs), sarcolemmal ionic currents (I_Ks, I_Kr, I_CaL, I_NCX) and intracellular Ca²⁺ concentrations (Ca_ss, Ca_i, Ca_SR) in the M cell versions of the original TP06 (A), mTP06a (B), and mTP06b (C) models. To mimic the pathological conditions of LQT1 and LQT2, g_Ks and g_Kr values, respectively, were decreased by 30–100%; individual APs are labeled by the numbers representing the residual g_Ks or g_Kr (%Control), with ionic currents and Ca²⁺ concentrations for each g_Ks and g_Kr value shown by the same colors. The horizontal dashed lines denote the 0 mV, zero current and zero concentration levels. Current amplitudes for the y-axis scale bars are given in pA/pF. The model cells were paced at 0.5 Hz, i.e., with the cycle length (CL) of 2 s for 60 min; AP waveforms, ion currents and Ca²⁺ concentrations after the last stimulus are shown as steady-state behaviors under each condition.