Hierarchical Reconstructions of Cardiac Tissue

We consider the general problem of comparing and integrating computational models of cardiac tissue at different levels of physiological detail. We use a general theory of synchronous concurrent algorithms to model spatially extended biological systems, and expand the theory to create hierarchical models by relating observable behaviour at different levels. The general concepts and methods are illustrated by a detailed study of electrical behaviour in cardiac tissue, in which models based on coupled systems of ordinary differential equations, partial differential equations and cellular automata are compared and combined.