Ace inhibitors and beta blockers work well together in different ways. Beta blockers slow the heart, decreasing it's requirement for oxygen. This is a good thing. People placed on beta blockers during and after a heart attack live longer, no doubt about it.
Ace inhibitors work to relax the blood vessels and make it easier for the heart to pump. Ace inhibitors also prevent cardiac remodeling, which can involve either hypertrophy, thickening of the heart wall or dilation, stretching the heart wall. Both hypertrophy and dilation make the heart less efficient which can be bad in the long run.
However, starting these medicines can have side effects, light headedness on standing, fatigue, sexual dysfunction, electrolyte abnormalities and more. Talk with your doctor to adjust your dose as needed.
You should also request prescriptions for generic medicines. There are plenty of brand name meds in these classes that cost more than generics, but haven't been proven any better.
Don't forget to take a baby aspirin each day!