What is a Heart Attack?

A heart attack is a layperson's term for a sudden blockage of a coronary artery. This blockage, which doctors call a coronary artery occlusion, may be fatal, but most patients survive it. Death can occur when the occlusion leads to an abnormal heartbeat (severe arrhythmia) or death of heart muscle (extensive myocardial infarction). In both of these situations, the heart can no longer pump blood adequately to supply the brain and other organs of the body. Almost all heart attacks occur in people who have coronary artery disease (coronary atherosclerosis).