We simulate elementary calcium release events (sparks) in a single calcium release unit in ventricular myocyte. Previously developed and tested electron-conformational model of the stochastic dynamics of RyR-channels is integrated to the calcium dynamics model in the cardiac cell. This approach allows to observe RyRs opening/closing in details on the macromolecular level during the calcium dynamics course. We simulate calcium diffusion in the dyadic space and “domino-like” RyR’s activation during the so-called “calcium induced-calcium release process”. Ca²⁺ sparks initiation, spread and termination are investigated in the computer experiments. Sparks’ initiation and termination rate dependence on the Ca²⁺ diffusion velocity is observed. We show that sarcoplasmic reticulum lumen local depletion and RyR’s stochastic attrition could be the reasons of Ca²⁺ spark termination.