Prenatal diagnosis of total anomalous pulmonary venous connection: 2D and 3D echocardiographic findings.

Total anomalous pulmonary venous connection (TAPVC) is a rare cyanotic congenital heart disease that accounts for less than 1% of all congenital heart diseases. TAPVC is characterized by the absence of pulmonary venous drainage into the left atrium. It is underdiagnosed in utero, with prenatal detection rates of less than 1.4%. The prenatal diagnosis of TAPVC affects the postnatal outcome, particularly in obstructive forms (critical TAPVC), since planned delivery and perinatal management are mandatory. Thus, identifying the ultrasound key markers of TAPVC is important for the prenatal diagnosis and perinatal assistance. The ventricular size discrepancy (right ventricle > left ventricle) can be a useful marker. Furthermore, the increased retroatrial distance between the left atrium and the aorta could be a diagnostic marker for prenatal TAPVC, especially when the left atrium is small. Three- (3D) and four-dimensional ultrasonography may improve the prenatal diagnosis of TAPVC. This study reviews the two (2D) and 3D ultrasonographic markers used in the antenatal diagnosis of TAPVC, with a focus on the tools that can be used by sonographers, obstetricians, and fetal medicine specialists to improve the prenatal diagnosis of TAPVC, and when to refer the case to a fetal cardiac specialist.