Study of calcium sparks and calcium wave propagation in cardiac cells

Abstract

Contraction of cardiac cells is initiated by an increase in the level of intracellular calcium concentration. The calcium response is the combination of the local stochastic release of tens of thousands of release sites. The possible responses range from sparks (local release) to a global calcium increase, passing from calcium waves that propagate along the cell. In this project we model the intracellular calcium dynamics as a network of excitable elements that fire stochastically, and study the occurrence of calcium waves and spark nucleation. In an initial part, we model the sparks of a homogeneous distribution of calcium nodes. We study the wave propagation of this model depending on properties accounting for the state of the heart. We develop a simplified mean-field theory which will shed light on various aspects of the dynamics of the model. In a second part, we proceed to add clustering onto our model, and with it, we study its new wave propagation and the dynamics of the model.