What is a heart attack?

Seek help immediately if you have any of the following:

  • pressure, fullness, squeezing, or pain in the chest.
  • a crushing, heavy, stabbing, or burning feeling in the chest
  • pain that spreads to the shoulders, neck, or arms
  • chest discomfort with lightheadedness, fainting, sweating, nausea, or shortness of breath

There are also other less common symptoms of a heart attack. No symptom of a heart attack should be ignored. How fast you respond and get help can make all the difference in your chances of surviving the attack and recovering successfully.


A heart attack is a medical emergency. Be sure you know the warning signs and what to do if you or someone you care for has them.

Doctors have a variety of names for heart attack - coronary thrombosis, coronary occlusion, or myocardial infarction. But no matter what it's called, the names all mean the same thing. The blood supply has been cut off to a part of your heart muscle.

What happens to cause a heart attack? The heart has its own blood supply. It gets its blood through a network of blood vessels called the coronary arteries. The right and left coronary arteries are the two major vessels in this network. There are also many smaller branches that circle the heart. A heart attack usually happens because one or more of these vessels has become blocked.

The blockage often begins as a buildup of fatty deposits called plaque. Plaque may completely block a coronary artery, or it may lead to a blood clot that blocks an artery. As a result, the cells of the heart muscle, or myocardium, don't get enough oxygen-carrying blood. Then the cells die.

How serious is a heart attack? How serious a heart attack is depends on what part of the heart is affected. It also depends on how much of the heart muscle is damaged. A blockage can affect the heart's ability to pump blood. Or it can interfere with the electrical signals that control the heart's rhythm. Such a blockage can result in abnormal heartbeats called arrhythmias.

Heart attacks usually occur over a 4- to 6-hour period. If the flow of oxygen-rich blood to a part of the heart is blocked for a period of 30 to 60 minutes, a heart attack usually occurs. The part of the heart that doesn't get the oxygen becomes damaged and dies. The longer a part of the heart goes without blood, the more cells die.


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