19 week anatomy scan-shadow on heart

anonnn

Today I had my 19week anatomy scan and they said they found a shadow on babies heart I can’t remember the medical term but they said that it’s usually a marker for Down syndrome but then went on to say how they don’t believe it’s likely because it’s just that one thing. I’m getting blood work done tomorrow to make sure .. this is my second and this is scary nothing like this with my first. Has anyone experienced this?