After the fontan ... what to look for

Our child, now 4, has had BiDirectional Glenn and ExtraCardiac Fontan to aid in correction of single ventricle physiology.
What concerns should I be conscious of ... cardiomyopathy, scar tissue, calcification, etc.?  I find myself reading TOO many articles that I become confused and overwhelmed. I want to see the future and be on top of signs that I may miss. She is doing well developmentally/physically and has good 02 sats and heart rate however I become concerned of 'overworking' the heart.  


This discussion is related to fontan surgery.