Teaching fetal hearts – why is it so difficult?

The first person to perform a fetal sonogram on a pregnant woman is by far the most important observer of potential fetal and newborn problems. Ultrasound examination has the potential to determine abnormal placentation, viability, fetal age, fetal number, amniotic fluid index, fetal movement, and make the mother and the family happy. That is a lot to ask of anyone when there are potentially so many things that can go wrong with the pregnancy, including the fact that 1/4 will end in miscarriage, while realising that more than 95% of all pregnancies scanned at 20 weeks’ gestation will have normal outcomes [1]. Scanning the fetal heart with ultrasound is considered the most difficult form of any ultrasound endeavour: major anatomic and functional anomalies can be missed [2]. Nonetheless, we recommend that a basic evaluation of the fetal heart using a simple protocol be performed at every prenatal ultrasound scan, including follow-up and indicated growth studies.
The referral indication for fetal echocardiography with the highest yield of true congenital heart disease (CHD) in our database and in other published articles is that of a questionable or abnormal fetal anatomy scan. Abnormal 4-chamber views account for the majority of fetal CHDs detected [3]. However, the most missed versions of CHD on fetal anatomy studies are conotruncal malformations including tetralogy, truncus, and transposition variants and great vessel anomalies including aortic and pulmonary atresias, coarctations, vascular rings, and interrupted aortic arch. Small ventricular septal defects (VSDs) and mild semilunar valve stenoses that we scan because of heart murmurs in well baby units are almost never seen in fetal echocardiograms [4].
My first boss in this business of perinatal cardiology, Bill Rashkind, often told me to go figure it out, explain what you found, then do it, then teach it. That was his version of the see one – do one – teach one rule. We got to do a lot of innovative stuff in the animal labs and of course in the cath lab. I had worked a bit as an undergraduate in the basement of the med school where some of the first ultrasound transducers were being made, so he assigned me to get the new A-mode ultrasound devise, which we attached to the cath lab recorder for m-mode recordings. If we did find something unusual with the heart in a child with ultrasound, Dr. Rashkind would say, “Let’s prove it in the cath lab.” I believe he would now say, “Let’s go fix it...


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