Hi,

I found your story of breastfeeding your first baby really inspirational - you did a fabulous job. It must be very stressful for you contimplating this little one's birth. He will so badly need your milk. But the good news is, you will be able to provide it for him. I think, first of all, you will want a long and honest talk with your caregivers about how important it is that your baby breastfeeds, and what support they can give you. Skin to skin, early expressing are a start. If she could remain with you for 48hours that would be fabulous. The simple question "why" is a good way to slice through what may be just unhelpful hospital convention and what is medical need.
If your baby can't feed at the breast, you might want to start hand expressing every 2-3 hours (remember you will get colostrum in the first days - just small amounts) Then by day 3 start pumping with an electric breastpump. You may like to hire one through ABA prior to your baby being born, so you know you have the right equipment on hand.
One issue with babies with a heart problem is that they have difficulty growing. They use a lot of energy. It's worth being prepared for this. Many mothers are pressured to into giving formula because of this. Your breastmilk will protect your baby from infection - and this is vital where there is a heart condition.
If you can express from 36 weeks I don't think this can do any harm. Get some 5ml syringes with caps from the hospital or chemist. This way, if he needs anything else it can be your milk
Let us know how you go - we will be thinking of you.