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Heart Attack

(Myocardial Infarction)


The Manual's Editorial Staff

Last full review/revision May 2021| Content last modified May 2021
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What is a heart attack?

A heart attack is when blood flow to part of your heart is suddenly blocked and some of your heart muscle dies. Doctors use the term myocardial infarction to refer to a heart attack. Myocardium is a word for heart muscle, and infarction is a word for blocked blood flow resulting in injury or death of the body tissue. So a myocardial infarction is a heart attack.

  • Go to an emergency department and chew on an aspirin tablet if you think you're having a heart attack

  • You may have chest pressure, shortness of breath, and a tired feeling if you're having a heart problem

  • Sometimes a heart attack may cause mild symptoms or none at all (silent heart attack)

  • Doctors do blood tests and ECG/EKG if you have symptoms of a heart attack

  • Doctors will give you medicine and do procedures to try to get more blood to the affected area of your heart

What causes a heart attack?

The heart is a muscle that pumps blood. Like all muscles, the heart needs a steady supply of blood to work. Blood that pumps through the heart doesn't feed the heart muscle. Instead, the heart muscle is fed by its own arteries. These arteries are called coronary arteries. Coronary is a word for heart.

Most heart attacks happen when one of your coronary arteries is suddenly blocked by a blood clot.

Coronary artery blood clots usually happen when you have atherosclerosis:

  • Atherosclerosis is commonly known as hardening of the arteries

  • Atherosclerosis is the slow build-up of cholesterol and other fatty material in your arteries

  • This build-up is called an atheroma or plaque

  • The plaque may rupture suddenly, causing a blood clot that blocks the artery

The blocked artery doesn't let blood get through to part of your heart muscle. If blood flow is cut off for more than a few minutes, that part of your heart muscle dies. The dead muscle can't pump blood, so your heart is weaker. Your heart's rhythm may also be affected, causing it to beat too fast or too slow. Sometimes your heart stops completely (cardiac arrest) and you die.

If part of your heart muscle dies, it doesn't come back. The dead muscle is replaced by scar tissue.

What are the symptoms of a heart attack?

Symptoms of a heart attack are similar to angina, but the pain usually hurts more, lasts longer, and doesn't feel better with rest.

  • You may have pain in the middle of your chest

  • The pain may spread to your back, jaw, or left arm

  • Less often, the pain spreads to the right arm

  • The pain may occur in one or more of these places and not in the chest at all

  • You may feel sweaty and nervous

  • Your lips, hands, or feet may turn slightly blue

How can doctors tell if I have a heart attack?

Doctors do tests, such as:

  • ECG/EKG—a test that measures your heart’s electrical activity

  • Blood tests to check for certain substances that show heart problems

How do doctors treat heart attacks?

You'll be admitted to the hospital. Doctors will try to:

  • Open up the blocked artery to save as much of your heart muscle as possible

  • Treat the problem that caused your heart attack

They will also:

  • Control your heart rhythm and blood pressure

  • Give you medicines to prevent blood clots

  • Give you medicines to lower the work load on your heart

Open blocked arteries

Depending on where your coronary artery is blocked, doctors may:

  • Give you medicine by vein to dissolve blood clots

  • Do angioplasty

  • Do bypass surgery

Clot-dissolving medicine given in your vein (IV) can open up a blocked coronary artery. However, the medicine works only if you get it within a few hours after your heart attack began. Also, the clot-dissolving medicine isn't for everyone. It may not be safe for people who recently had a stroke or major surgery, or people whose blood pressure is very high.

During angioplasty:

  • The doctor puts a small, flexible tube (catheter) into an artery in your upper leg (groin) or in your wrist

  • The catheter is pushed up the artery to your heart and then into one of your coronary arteries

  • A small balloon on the tip of the catheter is inflated

  • The balloon pushes the blockage open

  • Then the doctor slips a wire mesh tube (stent) off the end of the catheter into the blocked area

  • The wire mesh tube helps hold the blocked area open

During bypass surgery:

  • Doctors take a piece of healthy artery or vein from another part of your body

  • They sew one end of that piece of artery or vein to your aorta (the major artery that takes blood from your heart to the rest of your body)

  • They sew the other end to your blocked artery past the point of the blockage

  • Your blood then flows through this new route, bypassing the blockage

Treat the cause of your heart attack

To treat the problem that caused your heart attack, doctors usually give you:

They will also have you change any behaviors that are hurting your heart, such as smoking, not exercising, and eating a poor diet.

How can I prevent a heart attack?

Change behaviors that may hurt your heart

  • Eat healthy foods, such as fresh fruits and vegetables and other high-fiber foods

  • Eat less fat from meats, dairy, and processed foods (such as frozen pizza or microwaveable dinners)—talk to your doctor about how much and which types of fat you should eat

  • Lose weight if you need to

  • Stay active by using weights or walking

  • Stop smoking, drinking alcohol, or using drugs—these can be hard to stop, so talk to your doctor or a counselor about how to get help

Take your medicines correctly

  • Remember to take any medicines prescribed by your doctor, such as for high cholesterol, high blood pressure, or diabetes

  • If you're 50 or older, ask your doctor about taking a low dose of aspirin every day to help prevent heart attacks and strokes

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