Thank you very much for sharing your experience and advice.
Wish you and your family long & healthy life.
It's amazing what doctors can do now. My son was born with Transposition of the Great Arteries, a VSD and an ASD. After open heart surgery and 2 weeks in the hospital he is now a healthy 8 month old boy. No meds, nothing. Your baby is getting all his oxgygen from the mother right now, so no harm should come to the other baby or the mom (but i'm not a doc). Heart babies are never "cured", just fixed. I would advise checking out these websites ;
www.littlehearts.org
www.itsmyheart.org
www.childrensheartfoundation.org
Do a search to find a heart group in your area to help out when you are in the hospital (did you know 1:100 babies is born with a heart defect?)
Best luck to you and both of your children, congratulations! :)