How do you fewl day to day?
I don't think anyone can give you a prognosis here but I can tell you about my father. He has had two MI's and a 5 way bypass when he was 71. His second MI was 6 years ago when it was determined all but one graft was closed and he was basically living on collaterals. Since his MI, his EF% was as low as 29% and has never climbed above yours and he's now 88 going on 89 and getting along just fine.
Of course much depends on the reason for your low EF%, but work closely with your cardiologist. It's amazing how much can be done to manage your quality of life. If I can answer anything about my father's experience and his care, PM me and good luck! Jon