Many numerical simulations have been proposed to determine the mechanisms of cardiac excitation-contraction coupling. However, neither potential distribution nor mobility of the cytosol and ions has been taken into consideration in these models. We developed a 3D finite element model of cardiomyocytes based on triphasic theory to examine the significance of these factors in cardiac physiology. The salient feature of triphasic theory allowed us to study the behavior of solids (proteins), fluids (cytosol) and ions governed by mechanics and electrochemistry in an integrative manner in detailed subcellular structures, including myofibrils, mitochondria, the sarcoplasmic reticulum, membranes and t-tubules.
