Beta blockers are a type of medicine that is used to lower blood pressure, treat chest pain (angina) and heart failure, and to help prevent a heart attack. Beta blockers relieve the stress on the heart by slowing the heart rate and reducing the force with which the heart muscle contracts (to pump blood). If you have a heart attack, you should get a prescription for a beta blocker before you leave the hospital.

Higher percentages are better.

Source: http://www.hospitalcompare.hhs.gov