In a biventricular finite element model, adaptive myofiber reorientation of ~8° increased total pump work by 11-19%, whereas geometrical variations of 16-27% changed total pump work by only ~5%.
Does myofiber orientation or geometry have a greater influence on model predictions of cardiac function in a biventricular finite element model?
In mathematical models of cardiac electromechanics, implementing realistic myofiber orientation is at least as important as defining patient-specific geometry for predicting cardiac function.
In patient-specific mathematical models of cardiac electromechanics, usually a patient-specific geometry and a generic myofiber orientation field are used as input, upon which myocardial tissue properties are tuned to clinical data. It remains unclear to what extent deviations in myofiber orientation and geometry between model and patient influence model predictions on cardiac function. Therefore, we evaluated the sensitivity of cardiac function for geometry and myofiber orientation in a biventricular (BiV) finite element model of cardiac mechanics. Starting out from a reference geometry in which myofiber orientation had no transmural component, two new geometries were defined with either a 27 % decrease in LV short- to long-axis ratio, or a 16 % decrease of RV length, but identical LV and RV cavity and wall volumes. These variations in geometry caused differences in both local myofiber and global pump work below 6 %. Variation of fiber orientation was induced through adaptive myofiber reorientation that caused an average change in fiber orientation of 8^ predominantly through the formation of a component in transmural direction. Reorientation caused a considerable increase in local myofiber work (18\, \%) and in global pump work (17\, \%) in all three geometries, while differences between geometries were below 5 %. The findings suggest that implementing a realistic myofiber orientation is at least as important as defining a patient-specific geometry. The model for remodeling of myofiber orientation seems a useful approach to estimate myofiber orientation in the absence of accurate patient-specific information.
Pluijmert et al. (Wed,) conducted a other in Cardiac mechanics (mathematical model). Adaptive myofiber reorientation vs. Initial state (generic myofiber orientation) was evaluated on Total pump work. In a biventricular finite element model, adaptive myofiber reorientation of ~8° increased total pump work by 11-19%, whereas geometrical variations of 16-27% changed total pump work by only ~5%.
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