Computational modeling of ventricular-ventricular interactions suggest a role in clinical conditions involving heart failure

Figures

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  FIGURE 1. Cardiovascular model schematic with pressures (P), resistances (R), and compliances (C) indicated for the six model compartments with a pericardium encapsulating the left and right ventricles (LV, RV). SA—systemic arterial. PA—pulmonary arterial. SV—systemic venous. PV–pulmonary venous.

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  FIGURE 2. End-diastolic pressure-volume relationship (EDPVR) optimization and validation. (A) and (B). The left (red) and right (blue) ventricular model-predicted ex vivo EDPVRs (circles) plotted with the Klotz EDPVRs (solid black curve) for the optimized γ value. (C) and (D). Reproduction of the Klotz experiment (2006) (Section 3.1). The ex vivo EDPVR across various heart sizes with the Klotz EDPVR curve at a volume of 125 mL (solid grey). (E) and (F). The EDPVR curves from (C) and (D) with the volumes normalized according to Klotz et al. (2006). The normalized curves lay on top of each other. (G) and (H). The left (red) and right (blue) in vivo model EDPVRs (points) plotted with the Klotz EDPVRs (curves).

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  FIGURE 3. Healthy case at a mean systemic arterial, SA, pressure of 95 mmHg (baseline). (A). Left (LV) and right (RV) ventricular pressure-volume loops shown with approximated EDPVR curves (Klotz et al., 2006). (B). LV and RV volume time courses. (C). LV and SA pressure time courses. (D). RV, systemic venous (SV), pulmonary arterial (PA), and pulmonary venous (PV) pressure time courses.

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  FIGURE 4. Visualization of simulated ventricular geometry during the cardiac cycle in the healthy (A) and severe dysfunction (B–E) cases. The geometry of the Triseg model, representative of a biventricular transverse plane view, is illustrated at several times in the cardiac cycle, including start and end of systole and diastole with left ventricle (LV) on the left and right ventricle (RV) on the right. The overlap of the ventricular walls and septum follows from the simplifying assumption of the TriSeg model geometry. Dashed lines represent the TriSeg midwall, creating intersection points with balanced tensions. At end-diastole, LV and RV lumens are maximally full. During contraction, the walls progressively thicken until end-systole. In RV dysfunction, the effect of elevated RV preload on septal curvature is apparent at end-diastole, where the septum has become much more flattened compared to the other cases.

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  FIGURE 5. Left ventricular (LV) systolic dysfunction (SD) simulation. From the healthy (H) case, LV contractility is reduced (Section 2.5) for the moderate (M) and severe (S) cases. (A, B) The left (red) and right (RV, blue) ventricular pressure-volume loops at the healthy total blood volume for the H, M, and S cases shown with the healthy-case Klotz EDPVR curve (gray). (C, D). The end-systolic pressure-volume relationship and the end-diastolic pressure-volume relationship for the LV and RV. After volume loading, the baseline at full compensation is denoted by the black bolded marker. (E, F). The LV and RV pressure-volume at full compensation, corresponding to the markers in C and D. (G, H). The LV and RV Frank-Starling relationship curve for the H, M, and S case with baseline indicated by the black bolded marker.

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  FIGURE 6. Left ventricular (LV) diastolic dysfunction (DD) simulation. From the healthy (H) case, the LV passive stiffness is increased (Section 2.5) for the moderate (M) and severe (S) cases. (A, B). The left (red) and right (RV, blue) ventricular pressure-volume loops at the healthy total blood volume for the H, M, and S cases shown with the healthy-case Klotz EDPVR curve (gray). (C, D). The end-systolic pressure-volume relationship and the end-diastolic pressure-volume relationship for the LV and RV. After volume loading, the baseline at full compensation is denoted by the black bolded marker. (E, F). The LV and RV pressure-volume loops at full compensation, corresponding to the markers in C and D. (G, H). The LV and RV Frank-Starling relationship curve for the H, M, and S case with baseline indicated by the black bolded marker.

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  FIGURE 7. Right ventricular (RV) systolic dysfunction (SD) simulation. From the healthy (H) case, the RV contractility is reduced (Section 2.5) for the moderate (M) and severe (S) cases. (A, B). The left (red) and right (RV, blue) ventricular pressure-volume loops at the healthy total blood volume for the H, M, and S cases shown with the healthy-case Klotz EDPVR curve (gray). (C, D). The end-systolic pressure-volume relationship and the end-diastolic pressure-volume relationship for the LV and RV. After volume loading, the baseline at full compensation is denoted by the black bolded marker. (E, F). The LV and RV pressure-volume loops at full compensation, corresponding to the markers in C and D. (G, H). The LV and RV Frank-Starling relationship curve for the H, M, and S case with baseline indicated by the black bolded marker.

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  FIGURE 8. Right ventricular (RV) diastolic dysfunction (DD) simulation. From the healthy (H) case, the RV passive stiffness is increased (Section 2.5) for the moderate (H) and severe (S) cases. (A, B). The left (red) and right (RV, blue) ventricular pressure-volume loops at the healthy total blood volume for the H, M, and S cases shown with the Klotz EDPVR curve (gray). (C, D). The end-systolic pressure-volume relationship and the end-diastolic pressure-volume relationship for the LV and RV. After volume loading, the baseline at full compensation is denoted by the black bolded marker. (E, F). The LV and RV pressure-volume loops at full compensation, corresponding to the markers in C and D. (G, H). The LV and RV Frank-Starling relationship curve for the H, M, and S case with baseline indicated by the black bolded marker.

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  FIGURE 9. Cardiac power output (CPO) at baseline for healthy (H), moderate (M), and severe (S) cases for the four dysfunction simulations. Healthy-normal ranges for the left ventricular (LV, red) and right ventricular (RV, blue) CPO are indicated by the shaded regions. (A) LV systolic dysfunction (LVSD). (B) LV diastolic dysfunction (LVDD). (C) RV systolic dysfunction (RVSD). (D) RV diastolic dysfunction (RVDD).

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  FIGURE 10. Septal curvature time courses at baseline for the severe (S) case for the four dysfunction simulations with curvature at baseline for the healthy (H) case. Systole and diastole for the H case are indicated by the shaded regions. Positive curvature indicates bowing of the septum toward the right ventricle (RV) and a negative curvature would indicate bowing toward the left ventricle (LV). (A) LV systolic dysfunction (LVSD). (B) LV diastolic dysfunction (LVDD) (C) RV systolic dysfunction (RVSD). (D) RV diastolic dysfunction (RVDD).