Evacuability is inversely related to releasable amount of calcium in the SR. Symbols plot the initial value of E, calculated by an average of NFRC as described in Fig. 5, versus the corresponding R(∞), calculated on the same or a contemporaneous transient of adequate duration, for individual cells after varying times of exposure to 0 Ca. Colors identify individual cells. The blue circle and the large pink circle represent, respectively, the example WT cell of Fig. 2 and average values for 17 cells in reference solution. The continuous line plots the function E = ab/(R+b), with a = 334 mM⁻¹s⁻¹ and b = 0.0615 mM.