The short answer is yes. It doesn't happen a lot, but it does happen and the girl is lucky enough to have a second chance. Hopefully she won't have any use for a pediatric cardiologist after her initial visit.
In adults it can happen too, but it seems more rare in my andectdotal experience.
xtrasalt,
I rally have no idea without being able to review her full history and even then, the answer would be better posed to a pediatric cardiologist. There are some cardiomyopathies that can arise from myocarditis that may be self limited and some that are inherited that present early in life. The latter would probably be more likely to recur/progress.
This is a big step you are taking. Seeking a specialist in pediatric cardiology would be very helpful.
good luck