Calcium concentration in the myocytes is crucial in cardiac excitation-contraction coupling (the conversion of an electrical stimulus to a mechanical contraction of the heart cells). This part of the intricate process can be studied by simulating the calcium dynamics. In this project we consider a model that combines stochastic transitions among different states of channels and deterministic calcium dynamics and perform some computer simulations employing MATLAB. Then, we examine whether the model makes correspondence with empirical results taken from the Cellular Physiology Laboratory of the Cardiovascular Research Center (CSIC-ICCC) 2014/2015