Calsequestrin-Mediated Mechanism for Cellular Calcium Transient Alternans

(Biophysical Journal 95, 3767–3789; October 2008)

Instead of

$$\beta \left(c\right)={\left(1+\frac{K_C{B}_{\text{CSQN}}n\left(c\right)+{\partial }_{c}n\left(c\right)\left(c{K}_C+c^2\right)}{{\left(K_C+c\right)}^2}\right)}^{-1},$$ (1)

Eq. 18 should read

$$\beta \left(c\right)={\left(1+\frac{K_C{B}_{\text{CSQN}}n\left(c\right)+{\partial }_{c}n\left(c\right)B_{\text{CSQN}}\left(c{K}_C+c^2\right)}{{\left(K_C+c\right)}^2}\right)}^{-1}.$$ (2)

In Eq. 40, c_JSR and K_JSR should read c_NSR and K_NSR, respectively. With the corrected Eq. 18, alternans still occur, but at different parameter values. To illustrate this, we show in the figure below peak averaged cytosolic Ca²⁺ concentration on alternate beats during steady-state pacing, $c_i^{\text{peak}}$, as a function of pacing period T using the model with the original Eq. 18, here Eq. 1, (red circles) and with the corrected Eq. 2 (blue squares).

Fig. 1.

Peak averaged cytosolic Ca²⁺ concentration on alternate beats during steady-state pacing, $c_i^{\text{peak}}$, as a function of pacing period T using the model with the original Eq. 18, here Eq. 1, (red circles) and with the corrected Eq. 2 (blue squares). Values for parameters that differ from those in Tables 4–10 are ν_up = 0.36 μM ms⁻¹, B_CSQN = 460 μM, τ_u = 145 ms, and ξ = 0.4 (ξ is defined at the end of the section Diffusive Coupling).