Changing scene in cardiac embryology.

Recent significant advances in experimental embryology and experimental teratology of the heart contribute to the renaissance in studies of cardiac development. Examples taken from the author's laboratory demonstrate the need for reference points in the description of heart morphogenesis and speak against the existence of conus resorption. The discovery of animal models of congenital heart disease, e.g. Keeshond dog or fetal mouse trisomy, represent another promising opening in studies of pathogenesis of heart anomalies. To permit a reasonable understanding of the univentricular heart following basic questions need to be answered: a) what is the origin of its rudimentary cavity, b) what is the origin of its incomplete muscular septum, c) why are one or both great vessels attached to the rudimentary chamber, d) what determines the position of the rudimentary chamber and e) why may the great vessels be normally or abnormally arranged? The experimental analysis of the proliferative and growth pattern of the right ventricle as well as the studies on embryonic hemodynamic factors are presented as examples of how to approach these fundamental questions.