Figure 2. Effects of individual conductances on the Ca²⁺ transient (CaT).

(A) CaT amplitude defined as the difference ${\displaystyle \mathrm{\Delta }{\left[\text{Ca}\right]}_{\text{i}}}$ between the peak and diastolic values of the cytosolic Ca²⁺ concentration ${\displaystyle {\left[\text{Ca}\right]}_{\text{i}}}$ versus G/G_ref where G is the individual conductance value and G_ref some fixed reference value. (B) Time-averaged ${\displaystyle {\left[\mathrm{C}\mathrm{a}\right]}_{\mathrm{i}}}$ over one pacing period (${\displaystyle ⟨{\left[\text{Ca}\right]}_{\text{i}}⟩}$) versus G/G_ref. Illustration of the effect of varying ${\text{I}}_{\text{Ca},\text{L}}$ conductance (C) and ${\text{I}}_{\text{to},\text{f}}$ conductance (D) on AP and CaT profiles, where 50%, 100%, and 150% correspond to G_ref=0.5, 1.0, and 1.5, respectively. (E) Effect of varying RyR conductance on SR Ca²⁺concentration ${\displaystyle {\left[\mathrm{C}\mathrm{a}\right]}_{\mathrm{S}\mathrm{R}}}$ and CaT. Different time windows are plotted for the CaT and SR load (0 to 150 ms) and AP waveforms (0 to 50 ms) in (C-–E).