Flow in the early embryonic human heart: a numerical study.

Computational fluid dynamic (CFD) experimentation provides a unique medium for detailed examination of flow through complex embryonic heart structures. The purpose of this investigation was to demonstrate that streaming blood flow patterns exist in the early embryonic heart and that fluid surface stresses change significantly with anomalous alterations in fetal heart lumen shape. Stages 10 and 11 early human embryo hearts were digitized as calibrated two-dimensional (2D) cross-sectional sequential images. A 3D surface was constructed from the stacking of these 2D images. CFD flow solutions were obtained (steady and pulsatile flow). Particle traces were placed in the inlet and outlet portions of these two stages. Sections of the embryonic heart were artificially reshaped. CFD flow solutions were obtained and surface stress changes analyzed. Streaming was shown to exist, with particles released on one or the other side of the cardiac lumen tending not to cross over and mix with particles released from the opposite side of the cardiac lumen. Shear stress changes (stage 10) occur in the altered lumens. Streaming exists in steady and pulsatile flow scenarios in the embryonic heart models. There are differences in local shear stress distributions with surface shape anomalies of the fetal heart lumen. These observations may help shed light on the potential role of fluid dynamic factors in determining patterns of abnormal heart development.

Graphical and stereolithographic models of the developing human heart lumen.

Scaled physical models can be useful in analyzing stage-specific hemodynamics in the embryonic human heart to address correlations between early physical stressors and myocardial wall responses. We generated models of the cardiac blood space from reconstructions of four digitized human embryo images from Carnegie Collection at the Armed Forces Institute of Pathology. From physical scale models manufactured by stereolithography, compliant sleeves can be created for flow dynamics studies. This novel use of Carnegie collection images and graphical modeling software provides tools for broadening our understanding of normal and aberrant heart formation.