I'm currently doing research on a character, and this character happens to have a heart condition. She was born with it, and had corrective surgery as an infant and was told that everything was alright. That is until she was about twelve, and she was under extreme stress and she had a heart attack. Now she is sixteen and has continued problems with her heart, and is effected by strenuous activity and extreme stress. She takes medication to try and prevent future problems, but if she's not careful her heart might just fail. What I want to know is what kind of congenital condition can meet these criteria, and what kind of medication would be used to treat it? It can be multiple conditions related to each other if necessary, and I have been told by one person that it could be hypoplastic left heart syndrome (HLHS), because it requires surgery as an infant and can lead to future problems because surgery isn't always permanent and she can be restricted from exercise because her heart is weak. But is this congenital heart defect possible for this situation? I have no medical history, so it's not like I can figure this out myself.
I know what I've given you is difficult, but if you come up with a good answer that fits well with my character's history, I'll formally thank you in my novel if it gets published!!! Thanks for your time=)