Three topics of importance to modeling the integrative function of
the heart are reviewed. The first is modeling of the ventricular
myocyte. Emphasis is placed on excitation-contraction coupling and
intracellular Ca$^2+$ handling, and the interpretation of experimental
data regarding interval-force relationships. Second, data on use
of diffusion tensor magnetic resonance (DTMR) imaging for measuring
the anatomical structure of the cardiac ventricles are presented.
A method for the semi-automated reconstruction of the ventricles
using a combination of gradient recalled acquisition in the steady
state (GRASS) and DTMR images is described. Third, we describe
how these anatomically and biophysically based models of the cardiac
ventricles can be implemented on parallel computers.