I totally agree with Vienna, and think it's just likely that you have developed a bit more disease causing some ischemia. The EF is probably calculated from an echo scan? which means it is an estimate and could really be 50% or higher, meaning normal. It is important to note that it isn't all about the EF. If you have an ejection fraction of just 35-40% and no ischemia, it is possible you would feel much healthier than someone with an EF of 70% and ischemia.
People often think 100% is the normal. Not so. Healthy individuals typically have ejection fractions between 50% and 65% some sources consider an ejection fraction of 55-75% to be normal.
So most likely you have nothing to worry about yours 49% almost normal. But shortness of breath is an issue, so ask your doctor about more details; he should explain all the numbers from your latest ECHO, not only give you one number the EF %. Because you can have a normal ejection fraction reading and still have heart failure. If the heart muscle has become so thick and stiff that the ventricle holds a smaller-than-usual volume of blood, it might still seem to pump out a normal percentage of the blood that enters it. In reality, though, the total amount of blood pumped isn't enough to meet your body's needs.
Keep walking!