A Journey from Adult to Fetal Echocardiography

Abstract

As a cardiologist in a group practice or hospital settings, many a times you are requested to comment on fetal Echocardiography performed by radiologist or fetal medicine specialist. With overconfidence, we perform or comment on fetal echocardiography without knowing critical differences between adult and fetal echocardiography. First, fetal heart at 20 weeks of gestation is of the size of an almond. Due to the limitation of resolution of ultrasound machines, small size of fetal heart makes it difficult to visualize many direct signs of congenital heart defects such as total anomalous pulmonary venous connection (TAPVC), transposition of the great arteries (TGA), coarctation, and double outlet right ventricle (RV). Hence, in fetal echo, we use indirect signs and clues to diagnose these disorders. Second, there are two physiological shunts in fetal circulation; fossa ovalis and ductus arteriosus which make its very different from adult circulation. A cardiologist needs to know about indirect signs, special views, peculiar fetal cardiac defects, and hemodynamics of fetal circulation before attempting fetal echocardiography. Many of us have an impression that fetal heart is just a miniature form of adult heart. Fetal echocardiography is a lot different from adult or pediatric echocardiography because there are many structural and functional differences in fetal circulation. Moreover, many congenital heart defects such as TGA, TAPVC, and ventricular septal defect, can present with only subtle findings, so we need to be more vigilant while performing fetal echocardiography.