Dear Tarheel,
Typical OB ultrasound looks at a 4 chamber view of the heart without any Doppler (color or the spectral waveforms) to make sure that the heart is grossly formed normally. However, that's about it, so it's not nearly so comprehensive as a fetal echo. The heart is a complex three-dimensional structure that requires all kinds of different interrogations from multiple views, something that the typical targeted anomaly screen does not do. That's why the OB ultrasound is considered a "level II" study, while a fetal echo is considered "level III".
DiGeorge syndrome, a chromosomal anomaly where there is a deletion of a small portion of the long arm of the 22nd chromosome, is typically associated with much more complex heart defects. Can isolated VSDs be seen with diGeorge syndrome? Yes, but it's MUCH more likely that the VSD is an isolated finding without any gross chromosomal abnormalities.
We LOVE Asheville!
Thank you for your response. We found out its a small to moderate muscular vsd. I guess I'm worried because why was this not detected on ultrasound and only on fetal echo? Does this mean other things such as brain or kidney anomalies may have been undetected or is the heart just more intricate? Also are isolated muscular vsds the type you'd see with degeorges? My doctor didn't seem concerned but I read too much. Thanks again . And yes north Carolina alum :)
Dear Tarheel (I'm presuming North Carolina?),
Congenital heart defects occur in approximately 0.8 to 1% of all babies born. Ventricular septal defects are the most common congenital heart defect (after bicuspid aortic valve). They are most commonly NOT associated with genetic syndromes. In fact, we do not know why most heart defects occur in the absence of a genetic syndrome. And, genetic syndromes definitely make up the minority of the reasons for congenital heart disease. I obviously cannot promise you that your baby doesn't have a genetic syndrome. But, if your initial testing was normal and a targeted anomaly screen (level II OB ultrasound) was normal, the likelihood is quite low that there is an associated syndrome.
Having said that, in the end, ALL heart defects are due to some genetic change or difference that causes something to happen in the programming of the cells that create the heart. We just do not know or understand the vast majority of the processes or reasons that they happen. Most likely they are minimal changes that cause these isolated heart issues, with no other systemic abnormalities found. We hope to have more of this understood over the next decade, or so, though. However, we do not do any genetic "screening" for these because we wouldn't know what we'd be screening for.