Identification of congenital cardiac malformation and in utero arrhythmia by fetal echocardiography

M-mode, 2D and Pulsed Doppler Echocardiography were performed on 111 fetuses of high-risk pregnancies. Fetal gestation ages ranged 16-41 weeks. Six congenital cardiac diseases were detected in utero and confirmed at autopsy in 4 cases, and one by Pulsed Doppler Echocardiography after delivery. These included a rhabdomyoma, an endocardial fibroelastosis with hydrops, a pulmonary stenosis with tricuspid regurgitation, a VSD, a VSD with descending aortic stenosis, an AV canal defect with single atrium and single AV valve with regurgitation. Arrhythmia was diagnosed in 23 fetuses, 9 had transient sinus bradycardia, 8 had premature atrial contraction, 2 had premature ventricular contraction which disappeared after birth, 4 had sustained sinus bradycardia, one of them combined PVC occurring in bigeminy and trigeminy, which continued after birth. These 4 fetuses had congenital heart disease. Conclusion: (1) 2 DE and PDE are the most valuable non-invasive technique for detection of fetal structural cardiac abnormalities. (2) M-mode and PDE make correct rhythm diagnosis in fetus. (3) The fetus with transient sinus bradycardia or PAC usually has a favorable prognosis. Sustained bradycardia has a more ominous prognosis, particularly if associated with heart abnormalities. (4) Fetal hydrops may associate with congestive cardiac failure in uterus. The incidence of cardiac disease is high in hydrops.