Numerical Simulations of Calcium Ions Spiral Wave in Single Cardiac Myocyte

The calcium ions (Ca²⁺) spark is an elementary Ca²⁺ release event in cardiac myocytes. It is believed to buildup cell-wide Ca²⁺ signals, such as Ca²⁺ transient and Ca²⁺ wave, through a Ca²⁺-induced Ca²⁺ release (CICR) mechanism. Here the excitability of the Ca²⁺ wave in a single cardiac myocyte is simulated by employing the fire-diffuse-fire model. By modulating the dynamic parameters of Ca²⁺ release and re-uptake channels, we find three Ca²⁺ signaling states in a single cardiac myocyte: no wave, plane wave, and spiral wave. The period of a spiral wave is variable in the different regimes. This study indicates that the spiral wave or the excitability of the system can be controlled through micro-modulation in a living excitable medium.