As per your history , echo report and nature of treatment , it lloks mainly congenital heart defect - present since birth .
Consider following things in your case
1 Get second opinion
from Paediatric cardiologist
2 we need to monitor echo findings and also pressure readings from color doppler study.
3 avoid respiratory infections which are common , and get it treated aggressively if they occur
4 you may need opinion from cardiac surgeon
also - as surgery ca be one of the treatment option after detail evaluation .