Hi
I was where you are 26 weeks ago. My baby was diagnosed with ASVD and coarctation ofthe aorta (a narrowing in one of the branches of her heart.)
Its so scary, i was terrified through most of my pregnancy and had loads of other complications too. At birth it was discovered babys nose was blocked too.
We eventually decided to have the amnio at 33 weeks once the miscarriage risk passed as we had a few other factors for Downs syndrome and wanted to be prepared. It wasnt as bad as i expected it to be, and it came back clear for all genetic disorders.
But there is more good news.
She had open heart surgery at 8 days old. Your LO might not need that it is possible it could be fixed via keyhole surgery it depends entirely on the exact location of the defect and the surgeons preferences, it wont be determined until after baby is born when they can get better views of the heart.
Our LO survived her surgery, and recovered really well. we are being transfereed back to our home hospital tomorow but the only reason were not going home as LO has problems feeding due to her nose issue nothing to do with her heart.
We are staying in a ronald mcdonald house near the hospital and another family here had the same issues as us and there baby was discharged home four weeks after her operation.
It might not seem like it now but its good news they found this defect now as often it can be missed until after birth when baby gets sick, this way they can be prepared to help straightaway. You may not need immediate help depending on the seriousness of the hole our surgeon said if LO only had the hole he would have left it till she was a few m,onths older as it wasnt a large hole.
If you want to ask any questions feel free, im by no means an expert but will try to help best i can. Ive not included the scary parts of the statistics of the operation itself as i was well prepared to hear them when i was told and obviously our heart defect was a little different to yours but if you'd like to know the odds he gave us I can (they were better thsan i thought).
Also my biggest fear was what my little girl would look like with a scary horrible scar on her chest, but it was nothing like i thought. I took pics most days to see it healing I can let you see those as well if you like so you can see its not all bad.

Hope i helped a bit, its such a scary time but youll get through it.
Oh and DO NOT GOOGLE, google is not your friend. The only things you will find are worst case scenarios, dont do it.
The pic is me and my LO three weeks after her heart op.