FIGURE 3.

Simulated dynamics of the model HVM. (A) Steady-state behaviors of the AP, underlying sarcolemmal currents, and [Ca²⁺]_i transient. The model HVM was paced at 1 Hz with 1-ms stimuli of 80 pA/pF. Differential equations (Eqs. 55–64) were numerically solved for 20 min with the initial conditions appropriate to a resting state, which were determined by Eqs. 65–69 with [K⁺]_i fixed at 140 mM. Model cell behavior after the last stimulus (during the last AP) is depicted. (B) Rate dependence of APD, I_Ca,L, and [Ca²⁺]_i transients. The model HVM was paced at 0.5, 1, and 2 Hz with 1-ms stimuli of 80pA/pF. The differential equations were numerically solved for 20 min at each pacing rate; model cell behaviors after the last stimulus are depicted.