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). Most heart attack patients should be given a beta blocker within 24 hours of arriving at the hospital.

Higher percentages are better.

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