W.L.
Usually abnormalities in the heart go away. It's mostly due to the baby still developing. That's why if they are born that early they cant live because they are still developing. I'm sure one of the main reasons your doc wants you to have another ultrasound from someone that knows more about it than they do is just to rule everything out if they can and if there is something wrong they can prepare for the birth. Meaning they can have the necessary doctors there to look at your little baby boy and be sure he's ok. I would do the ultrasound if I were you as a previous post said if for nothing else to ease your mind. We always worry about the worst when we are pregnant and usually it's worrying for nothing. I"m 12 weeks along now and feel like I can breathe i'm over the worry hump. Go have your ultrasound hunni! Plus you get to see your baby again!
Best Wishes,
W.