Multiscale Modeling of Calcium Dynamics in Ventricular Myocytes With Realistic Transverse Tubules.

Spatial-temporal Ca^2+ dynamics due to Ca^2+ release, buffering, and reuptaking plays a central role in studying excitation–contraction (E–C) coupling in both normal and diseased cardiac myocytes. In this paper, we employ two numerical methods, namely, the meshless method and the finite element method, to model such Ca^2+ behaviors by solving a nonlinear system of reaction–diffusion partial differential equations at two scales. In particular, a subcellular model containing several realistic transverse tubules (or t-tubules) is investigated and assumed to reside at different locations relative to the cell membrane. To this end, the Ca^2+ concentration calculated from the whole-cell modeling is adopted as part of the boundary constraint in the subcellular model. The preliminary simulations show that Ca^2+ concentration changes in ventricular myocytes are mainly influenced by calcium release from t-tubules. [ABSTRACT FROM AUTHOR]