This lightens the workload for
heart to pump against by dilating the vessels.
Coreg also has a component to stabilize
heart rate. Do you or is it suspected you may be susceptable to tachyarrhythmia. A TWA and Coreg medication seem to imply.
You can take a stress test, with the injection of a dye substance, to determine the viability of the damaged heart muscle.
I had an MI 4 years ago with an EF29-13% and some heart muscle damage at the distal portion of the heart.