What is a Heart Attack?

When someone says "I think I'm having a heart attack," do you know what that actually means?

The Heart is a Pump

First, imagine a pump, like a water or gas pump. Your heart is a pump too, but instead of being made of metal and rubber, it's made of muscle. That muscle is called the myocardium. It's about the size of your closed fist, and it's fed blood through a series of arteries, called "coronary arteries."

Clogged Arteries

A heart attack happens when the heart's supply of blood and oxygen through one of those arteries is cut off. Usually it's a clot that causes the blockage. Clots break off from plaque, a collection of fatty tissue, cholesterol and old cells that hang out in your arteries in a process known as atherosclerosis. In other words, when we joke about our Thanksgiving dinner clogging our arteries, we are unknowingly referring to atherosclerosis.

A Heart Attack is Dying Muscle

When a clot blocks an artery, the part of the heart muscle that is fed by that artery will start to die. If the blood supply is cut off for more than a few minutes, the person will have a heart attack. Depending on how much heart muscle is damaged in the heart attack, the person can die or be seriously ill.

To add insult to injury, even if the person survives the initial heart attack, scar tissue from the dead area of muscle still affects how efficiently the heart pumps. The scar tissue pumps less blood than healthy heart muscle, which can eventually lead to heart failure.

You will sometimes hear a heart attack referred to as a myocardial infarction, or MI. That refers to the myocardium, the muscle that is damaged when a coronary artery is blocked.

Another Heart Attack Cause

Sometimes it's not a clot that causes a heart attack, but something called a "spasm." For reasons doctors don't yet understand, a coronary artery will sometimes have a spasm and narrow. When that happens, the blood and oxygen flow to the heart is cut off, in the same way a clot might. If the spasm is severe enough, a heart attack is the result.

Symptoms of a Heart Attack

Ask anyone what the symptoms of a heart attack are, and the first thing they are likely to tell you is chest pain. But there are many more signs and symptoms of heart attack -- and some people have no obvious physical symptoms at all.

Here are common signs and symptoms of a heart attack:

* Chest discomfort: This can range from pain, to pressure, to an unusual feeling of "fullness". It may be steady, or it may come and go. It's usually in the center of the chest, but not always.

* Discomfort elsewhere: The pain may be felt in the arms (especially the left arm), the back, neck, jaw or shoulder. The pain may begin in the chest, and then radiate - or move - somewhere else.

* Upset stomach: Someone who is having a heart attack may feel nauseous, and may vomit or have diarrhea. They may also have pain in their upper abdomen that can be mistaken for upset stomach or indigestion.

* Shortness of breath: A heart attack victim may feel like he/she is having trouble breathing.

* Feeling of impending doom: People experiencing the physical symptoms of a heart attack often say something like "I feel like I'm going to die". Believe them, and call 9-1-1 or your local emergency number as quickly as possible.

* Other symptoms: Someone who is having a heart attack may also break out in a cold sweat, look pale and feel dizzy or lightheaded.