Worrying

I went for a growth scan today and during the scan they spent soooo long looking at the heart and whispering to each other, I could only hear little bits of what they were saying like “get her last scan up”...

After some time one of the women said “I’m ok with that” so I asked if something was wrong with baby’s heart and they said “no no, just checking that it speeds up and slows down as normal”

I’m worried that they thought they saw something that wasn’t right! Has this happened to anyone before?