Eif(bright spot on my babies heart) help.

So my quad screen came back negative for every thing, then i had my 20wk ultra sound and it came back that they saw a little light spot on my babies heart, the doctor told me that with every thing else looking perfectly fine along with my quad results i should not worry because there are typically more markers for downs and that a bright spot is very common in normal pregnancies.... Have any of you mother's ever had this happen?