Figure 10

Chamber Pressure-Volume Relationships using Different Septal Models. P-V relationships for the four cardiac chambers shown for three septal model cases – case a: passive septum with ESPVR only (red); case b: passive septum with EDPVR only (blue); case c: active septum with ESPVR and EDPVR modulated by an activation function (see text for details). For case a, the stiff, unstressed septum reduces V_LV, increasing end-diastolic P_LV and restricting LV filling, while increasing systolic P_RV due to no leftward movement, and not contributing to RV ejection. In case b, the less-compliant, rightward-shifted septum expands V_LV and reduces V_RV overall, increasing systolic P_RV and contributing little to ventricular ejection (Panels C-D). In both cases, the reduced cardiac output decreases P_RA (Panel A) and end-diastolic P_RV (Panel C). Reduced stroke volume causes blood to accumulate in the pulmonary bed, increasing P_LA (Panel B).