The Use of Fetal Echocardiography to Uncover an Incidental Finding in Late Gestation

Late-term fetal echocardiography can be challenging due to fetal position, acoustic windows, and difficulty obtaining all the necessary cardiac views. These challenges can create temptation to delay diagnostic cardiac imaging until after birth, in late third trimester patients. However, there are many critical cardiac diagnoses that can be harmed by that approach, leading to gaps in knowledge and care in the immediate perinatal period. Urgent referrals for fetal echocardiography in appropriate settings are essential, even in the third trimester. Isolated total anomalous pulmonary venous return (TAPVR) is an uncommon but serious form of critical congenital heart disease that is rarely diagnosed, in utero, but illustrates the vital importance of prenatal diagnosis, before birth. In this case study, a late term patient was urgently referred for fetal echocardiography for right/left heart discrepancy, at 37 5/7 weeks. Because of right ventricle enlargement a coarctation was suspected. A full fetal cardiac evaluation demonstrated a “twig sign,” not appreciated on the detailed obstetric sonogram, which led to a diagnosis of obstructed infradiaphragmatic TAPVR. Isolated TAPVR is difficult to diagnosis prenatally, with a detection rate of 2-10% but requires emergent evaluation and surgical repair soon after birth. This unique late term case study highlights the importance of urgent cardiac referrals, even in late gestation when delivery is imminent.