Heart failure is not an incident, like a heart attack, but a chronic condition, like arthritis or emphysema. Also, it seems to be very fuzzy in diagnosis. My cardio says that I am still in heart failure after my surgery, even though I'm down to 12% body fat, lifting weights 5 days a week, and preparing to run a 5K at the end of this month. Even at my worst, the right meds kept me feeling pretty good and helped to improve my heart function somewhat, despite having an aortic valve that was both stenotic and leaking. So, even though you probably don't want to wait longer than necessary, don't panic about the heart failure thing. You can measure LVEF, the mass of your heart, or its diameter, but what is most often referred to in assessing a heart failure patient's condition is NYHA Functional Classification, which classes patients according to how well they function. So you are, in a sense, as healthy as you feel.
So Anne, what do you feel up to doing? If you went for a run right now, would you feel alright? Does a good walk make you feel all out of breath? I know it gets said over and over but, listen to your body. Even a severely weakened heart benefits from some exercise, so don't stop unless either your body or your doctor tells you to. (And I wouldn't be surprised if your doctor tells you to listen to your body.)