MY almost 5yo dd1 was diagnosed antenatally with a congenital heart defect - she had a complete Atrial Ventricular Septal defect - AVSD and a dodgy av valve.
IT was a very scary time - we did a lot of research so we knew what we were dealing with - found it especially helpful hearing from other parents about their experiences.
THe positive in knowing antenatally is that everything was in place in terms of dd1's post birth care. We toured the special care/icu unit at our local hospital where dd1 was born, we already had the referrals to the London hospital that did her cardiac surgery etc. So what would have been a worrying time post natally wasn't - so much was in place that we felt okay about it all - iyswim.
Dd1 had surgery at the Royal Brompton when she was 8 weeks old. Since then she has not looked back - she is an amazingly healthy little girl. Whilst her av valve is still slightly leaky and may mean surgery as a teen or later if the valve needs further repair - she just has annual check ups at this stage.
It can be a very worrying time but I felt knowing what was to happen and I also had more specialised care which helped ease my fears. FOr us researching and informing ourselves of what was ahead was also very helpful.
Despite having a heart defect - I had the opportunity to have a vaginal birth - did not work out that way - other factors to do with me meant I had an emergency c-section. So I can't imagine how dh and I would have coped if we did not know and she was rushed to ICU etc on top of an emergency section.
Talk toy our consultants - ask all the questions you can think of - no matter how silly or small they seem.
Heartline were also helpful for us to refer to.
HTH