Description: This module is Module 3 in a 13 Module Pediatric Echocardiography eCourse series. For information on the full Pediatric Echocardiography eCourse, please click here. This module covers cardiac development with special emphasis on those areas of cardiac embryology that lead to certain types of congenital defects. A solid understanding cardiac development and embyrology can greatly enhance the understanding of certain defects. The fetal circulation is a critical part of early development. It is important to understand the normal physiology of the fetus in order to understand how birth defects affect the fetal circulation in-utero as well as after birth.