Echogenic heart focus....

I've done my research, my quad screen came back negative like 1 in 10,000 for downs, but then i had my 20week u/s and they say they saw a small eif(bright spot in babies heart) that is a soft marker for downs but typically resolves on its own and doesn't mean my girl has chrom defect, and it is very common in healthy pregnancy, my doctor told me not to worry because typically there would be other markers and there is none and it could just be a build up of calcium, some one that has experienced this please comment, i need some peace of mind