Heart Embryology: Overview

Human heart has a complex embryological development process driven by genetic mechanisms that have successive and unitary progression in a global context together with other developments of organogenesis. The first elements of cardiogenesis occur prematurely from mesoderm where cellular differentiation at this level acquires cardiogenic specificity by creating the first heart field. From this stage, cellular multiplication is specific for myocardial, endothelial, and smooth muscle cells through the second heart field. Accordingly to up-to-date evidence, the mechanisms of this process are genetically coordinated mainly by NKX2.5, GATA4, Mef2, TBX5 and Hand which establish not only the structure of the embryonic cord but also the sequential evolution of the differentiation and completion of the cardiac structures including the inlet and outlet paths. First field and second field are the initial particular stages of cardiogenesis. In the primary heart tube, the differentiation into adult anatomical cardiac structures (the atrial and ventricular cavities) begins. The heart tube looping initiates the separation of the primitive atria, ventricle and outflow tract. The separation between these cavities is made by different but concordant mechanisms. Coronarogenesis is the last stage before embryonic heart becomes functional.