Figure 4 - 34 . embryology of the atrioventricular junction . the primitive atrioventricular canal is partitioned by the growth of the endocardial cushions ( ec ) , interatrial septum ( ias ) , and interventricular septum ( ivs ) 房室交界处的胚胎发育。原始房室管生长分化为心内膜垫（ ec ） ，房间隔（ ias ）和室间隔（ ivs ） 。
Results : there are 20 cases of fchd , in which 2 cases is of endocardial cushion defect , 3 of atrial septa defect , 2 of single atrium , 2 of single ventricle , 2 of double outlet of right ventricle , 2 of ebstein ' s malformation , 5 of interventricular septal defect , 2 of fallot ' s tetrad . 16 cases were diagnosed by ultrasonography and 4 cases were missed diagnosis in prenatal 结果：发现20例胎儿有先天性心脏缺陷，其中完全性心内膜垫缺损2例，原发孔性房间隔缺损3例，单心房、单心室、右室双出口、三尖瓣下移畸形各2例，室间隔缺损5例，法乐四联症2例。
