1. In Vivo Left Ventricular Geometry and Boundary Conditions

The first basic biomechanics modeling step outlined in the introductory chapter is to define the geometric configuration. In Chapters 12 and 14 we demonstrate the application of either simple (i.e., axisymmetric truncated ellipsoid) or complex (i.e., fully 3-D) left ventricular (LV) geometric models or finite element (FE) meshes. This chapter is primarily concerned with an instructive review of the methodology we have used to create both types of FE meshes, which relies on the “parametric” meshing software TrueGrid^®. Since TrueGrid is rather expensive, Section 1.6 describes the use of free software executables available from the Pacific Northwest National Laboratory. The second basic biomechanics modeling step (determine mechanical properties) is addressed in the next three chapters. The third and fourth basic biomechanics modeling steps (governing equations and boundary conditions) are discussed briefly at the end of this chapter.