Figure 9. Rate dependence of Ca²⁺ dynamics.

The myocyte was paced as previously [44] with a pacing frequencies [1], [2], [3] Hz. Each pacing frequency was applied for 5 minutes in a continuous stimulus train. Rate dependence of Ca²⁺ dynamics (A) matches qualitatively to the force-frequency relation (B) reported by Sossalla et al. [44]. (C) Changes of Ca²⁺ transient dynamics in response to fast pacing. (D) Ca²⁺ influx via the reverse mode of the NCX (right panel) increases substantially during fast pacing, whereas the influx via the LTCC is decreased slightly (left panel).