Heart attacks occur when blood flow through the arteries to the heart is blocked for a long enough time to damage or kill a portion of heart muscle. Although some people with heart attacks die immediately, most survive. Doctors usually recommend that these survivors take several drugs. They often prescribe drugs called angiotensin-converting enzyme (ACE) inhibitors because several studies showed that these drugs helped prevent future heart attacks and death. However, there are many different ACE inhibitors, and some were not tested in the trials. Most doctors think that all ACE inhibitors have similar effects; however, some of these drugs might prevent future heart problems and death better than others.