Optimization of cardiac fiber orientation for homogeneous fiber strain at beginning of ejection

Influence of left-ventricular shape on passive filling properties and end-diastolic fiber stress and strain

“…The left ventricle was modeled as a truncated thick-walled ellipsoid with circumferential symmetry as often done in modeling studies such as Bovendeerd et al (1992), Rijcken et al (1997) and Vendelin et al (2002). The real geometry of the left ventricle does not exhibit the same degree of symmetry, but it is assumed that this approximation contains the major characteristics of the LV shape while allowing for a more simplified mathematical description of LV mechanics.…”

“…Bovendeerd et al, 1992;Rijcken et al, 1997;Vetter and McCulloch, 2000;Vendelin et al, 2002). However, the focus of these studies has been mainly on tissue elasticity or fiber orientations, assuming a certain shape of the left ventricle based on gross anatomical measurements.…”

Modeling of cardiac growth and remodeling of myofiber orientation

“…Parameter p 3 represents the maximum value of a t , occurring at the apex at midwall. Maximum homogeneity of fiber strain at begin ejection was obtained for p 1 ¼ 21:0 o , p 2 ¼ À69:2 o and p 3 ¼ 15:3 o (Rijcken et al, 1997). These parameter settings remained virtually unchanged when homogeneity of fiber strain during ejection was added as an optimization criterion .…”

“…In later studies, the optimization of fiber orientation was performed automatically by coupling a model of LV mechanics to an optimization algorithm (Rijcken et al, 1997. The spatial distribution of the helix and transverse angle was described by a three-parameter model:…”

“…Model studies: solutions from optimization models with linear transmural distribution (thick dashed gray line) from Rijcken et al (1997) and nonlinear transmural distribution (thick solid gray line) from Bovendeerd et al (1999); solution from adaptation model (thick dashdot gray line) from Arts et al (1994). the actual physiological adaptation process, in which a local stimulus leads to a local change.…”