An MI with heart cell damage to the septum does not have much effect on the heart's ability to pump adequately as shown by your low normal EF (normal 50-70%). That is because the septum (wall between left and right chambers) remains somewhat rigid as the pressure within each chamber applies almost equal pressure against the septum during systole.
There appears to a lower unexplained drop in the EF from 53% to 47%. If you consider the margin of error of about 5%, your EF is about the same. Also, the EF is variable as is the heart rate and blood pressure. All 3 factors adjust to various levels and are interrelated to maintain a balance of blood flow between the right and left side. When the heart normally dialtes that causes stronger contraction and more blood is pumped with each stroke, etc. So it is not unexpected to have a variation of the EF from one test to another.
Hope that gives you a perspective, and feel free to respond if you have any further questions. Take care and thanks for sharing.
With regards to activities, the saying goes that you can do anything you like as long as you slow down if you feel strange symptoms. For example, if you feel light headed, chest pains, throat discomfort, sudden jaw ache, pains in arms/shoulders etc, then just ease down and let your heart and circulatory system go down a gear. You have to basically learn your own limitations because every single person is different. If you do feel chest pains starting, just stop what you are doing and they should vanish within a couple of minutes.
It appears Cindy707 has given you advice to consult with a doctor on a previous post regarding your concern with exercise. It appeared you were concerned with your EF differential on this thread, and I answered that concern.
Ed has expressed it well and addresses your activity concern, and I agree with his perspective on the subject as it really comes down to what your response is to a particular activity. For instance a particular activity may be considered OK, but one may be under more stress on a particular day, cold weather, or had just eaten a large meal, etc. and to engage in a particular activity that had been considered safe may pose a risk, and under those circumstancesbe it would be prudent to slow down or stop the activity. Also, learn your own limitations, but based on the results of a stress test, you have very few activities limitations.
In response to another thread....Don't be confused! An "angio" (angiogram) is by definition an evaluation of the coronary arteries with a contrast medium. Several months ago I had a CT angiogram 128 slice and that does not have the risk associated with a cath angiogram or any other cath intervention and the risks includes blood clots (responded recently to post with that condition), there can be infection at the site of the cath penetration, there can be rupture of the vessel lining, etc. The cath angiogram has the advantage of a stent implant at the time of the procedure.
The CT scan (state-of-the art 258 slice has very little radiation risk and doesn't require slowing the heart rate below 60bpm, and the presentation is 3D and shows blood flow (the fourth dimension). The CT angiogram has the advantage of viewing the anatomy of the vessels and that includes the soft plaque within one of the three linings. Soft plaque has the highest risk, and that risk is the rupture of the soft plaque into the lumen channel), and that event is accountable for the largest percentage of heart attacks as any cardiologist will trell you. The CT also views the lumen for any hard plaque. Inaddion, the procedure views lungs, aorta (ascending, arch and descending). I was pleased with the outcome of my test although there was high calcium score indicating soft plaque.
There indivduals that have normal EF and don't feel well, and individuals with an EF below 30% and feel well. In fact there are about 26% of the heart population that don't know they have a heart problem and carry on with their regular activities. There are many medical variables and some variables compensate very well for heart failure.