Figure 2.

TriSeg model of ventricular mechanics. (a) The TriSeg model (gray shading) incorporated in the modular CircAdapt model of the systemic (syst) and pulmonary (pulm) circulations.3 Three thick-walled spherical segments representing LV free wall (LW), RV free wall (RW), and septal wall (SW) form a ventricular composite consisting of a left ventricular (LV) cavity, with volume V_LV and pressure p_LV, and a right ventricular (RV) cavity, with volume V_RV and pressure p_RV. (b) Cross-section of the ventricular composite through the axis of rotational symmetry (x). The ventricular walls are coupled mechanically at the common junction circle where their midwall surfaces (thick lines) meet. This junction circle perpendicularly intersects the plane of drawing (open dots). The midwall surface divides the wall with wall volume V_w in two shells of equal volume. The center of the junction circle is the origin (0) of the cylindrical coordinate system applied. Note that x-direction is defined positive toward the RV free wall. (c) Cross-section of a single wall segment through the axis of rotational symmetry. Note that only midwall geometry is shown. The shaded area indicates midwall volume V_m enclosed between the midwall surface and the junction plane. Midwall volume V_m, area A_m, and curvature C_m (reciprocal of radius of curvature) depend on distance x_m and radius y_m of the boundary circle. Each wall is loaded by transmural pressure difference resulting in a representative midwall tension T_m. With half opening angle α, T_m is resolved in an axial (T_x) and a radial (T_y) component