Are Beta blockers and Ace inhibitors really indicated after all stents?

I am 56, had one drug eluding stint placed on Feb 12 in upper LAD with 90pct block. Microscopic damage to the heart muscle still have ejection fraction of 60pct. This was called a NSTEMI This is my first problem ever.  I refused a beta blocker and lisinopril becasue pre and post stent I have never had HIgh BP or tachycardia.  I did take new aspirin regimen of 81 daily plus 75 of Plavix and Lipitor for a previously known High cholersterol I had refused to treat.
Question is.  Why ace inhibitor and beta blockers when I am not presenting any problems of HBP or HR?

[CCF HeartMD6]

Beta blockers work in a number of different ways which include lowering blood pressure, preventing arrhythmias, and decreasing the stress of the heart (the latter two being the main reasons for why they are prescribed following a heart attack).  ACE inhibitors also are prescribed for blood pressure, but also help prevent any negative remodeling of the heart (structurally) following a heart attack.  While you are correct that both of these medications are used for hypertension/blood pressure control, they actually have other mechanisms of action that are beneficial for your overall cardiovascular health.  Unless there are contraindications for taking these medications (extremely low heart rate or blood pressure, heart block, or conduction disease, renal dysfunction, or an allergy), individuals with a history of a heart attack should be on these medications as prescribed by your cardiologist.

[Jbird1234]

How does this new study favorite in? http://www.m.webmd.com/a-to-z-guides/news/20120927/common-heart-drug-questioned