Finite element modeling of blood flow-induced mechanical forces in the outflow tract of chick embryonic hearts

Forces exerted by the flow of blood on the walls of the embryonic heart, such as pressures and shear stresses, influence heart development; and deviations from normal flow conditions lead to structural defects. To better understand the effect of blood flow on the development of the heart, it is important to characterize the hemodynamic forces that act on the heart walls. Other studies have attempted to quantify such forces. However, shear stresses on the heart walls cannot be measured directly, and quantifications using in vivo velocity measurements are not yet accurate due to the challenges of obtaining velocity profiles near the moving walls of a beating heart. The objective of this work is to quantify hemodynamic forces on the heart wall of chick embryos that are about 3.5 days of incubation (stage HH21), using a combination of physiological data and finite element (FE) models. We focused on the heart outflow tract (OFT) since at this stage the development of the OFT is very sensitive to hemodynamic forces. In this paper, we present a three-dimensional dynamic FE model that is based on a series of ultrasound images of the OFT. Simulations of the FE model, performed for the ventricular ejection phase of the cardiac cycle, showed a complex blood flow pattern within the OFT and gave temporal and spatial distributions of shear stresses and pressures at the inner surface of the OFT wall.