Annihilation of the pacemaking activity in the sinoatrial node cell and tissue

Sinus node arrest is a dangerous disease, which is associated with the annihilation of the cardiac biological oscillators. The present work investigates in detail the pacemaking annihilation of the modeled single SAN cell and heterogeneous tissue by the conventional nonlinear dynamics approach. It is found that annihilation should generally exist in the SAN system, which is due to the subcritical Hopf bifurcation. However, the annihilation is strict with the stimulus and the physiological parameters, for which the difficulty is estimated. Intracellular calcium cycling makes the pacemaking more robust against annihilation. Furthermore, some general methods for exploring the annihilation dynamics are demonstrated, which may be helpful for the investigations of the other complex biological oscillators. The present work may provide suggestive ideas for the treatments of the sinus arrest and the relevant arrhythmogenesis.