Did your newborn have a congenital heart defect?

My baby has a missing valve and the 2 he has are fused together. He'll need surgery to separate the 2 and depending on how that goes he might need open heart surgery to replace them in the future.. Shouldn't they have noticed in the ultrasounds? They didn't hear the murmur until his 2 week checkup...just wanted to hear from someones who's been through this feel free to share your stories...