Computer model for determining localized changes in ventricle wall thickness as a function of changing wall stress determined by Laplace's law

The ventricular myocardium remodels in an attempt to normalize local wall stress (σ) created by physical forces and optimize cardiac function. This σ is considered a major driving determinant of growth or regression of myocardial cells that in turn change the local ventricular myocardial wall thickness (h) and area stress. A computer model was developed that describes the magnitude and time course of changes in h in response to variations in physical factors (pressure, geometry). The model algorithm describes the driving changes in myocardial protein synthesis and h based on a stimulus of wall stress (Δ
_s
) outside of the normal range (σ
_ο
). Changes in the segmental wall thickness (dh/dt) are considered directly related to the differential in σ integrated over time. As h changes, the actual wall stress (σ
_o
) also changes as defined by Laplace's Law. The iteratively determined σ drives the growth/atrophy of the ventricle wall until an equilibrium is reached and Δ
_s
= 0. Model performance was compared to values from the literature that examine changes in σ
_a
during a clinical perturbation and was found to closely map changes in σ
_a
with an exponential approach to a maximum loss of about 35% of total h at 60 days with a k value of 0.0006. This model can serve as a driving algorithm for defining myocardial plasticity in a FEM of the heart and used to study cardiac remodeling.