It is interesting that she had cardiac surgery as an infant. It does remind me of the situation of an acquaintance where the patient had cardiac problems as an infant/toddler that were fixed and then essentially moved on until they suddenly dropped dead (while apparently fit and healthy) in their early twenties. One one hand you'd think gee, maybe if you had such a rough start they would follow you up with a super-duper checkup every few years or so. On the other hand, I guess when the invincibility of youth sets in, no apparently healthy person wants to go to the doctor and relive their past.
Edit: sorry - s/she/you, didn't realise the HN comment was by the original author.