VISUAL UNDERSTANDING OF CARDIAC DEVELOPMENT - THE NEURAL CRESTS CONTRIBUTION

Understanding normal and abnormal cardiovascular development is of int erest to basic scientists as well as to clinicians taking care of infa nts with heart defects, This article presents a visual overview of car diac development, It provides a framework on which to understand how a bnormal cardiac development leads to groups of cardiovascular defects requiring clinical care, Human heart development is presented schemati cally and is correlated with similar points in chick cardiac developme nt, Studying both normal and abnormal cardiac development in neural cr est-ablated embryos has highlighted two major themes of cardiac develo pment: there is a mechanism of differential growth in the developing c ardiovascular system that is not seen to a major extent after birth an d cardiac defects can be pictured as arrested stages of normal develop ment, At a particular stage of development, it is normal to have a cer tain relationship between developing structures, However, if the devel opment is arrested and this relationship of structures is allowed to p ersist, it then becomes abnormal, Visualizing heart defects as arreste d points in normal development is better used as a tool to categorize defects than as a causative mechanism, The exact mechanisms of how abn ormal development results in cardiac defects is not well understood, S tudy of the neural crest model of cardiac defects suggests possible me chanisms.