Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Heart Attack

(Myocardial Infarction)

By

The Manual's Editorial Staff

Reviewed/Revised Apr 2023
VIEW PROFESSIONAL VERSION
Get the full details
Topic Resources

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.

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.

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

  • 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?

  • 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

Myocardial Infarction
VIDEO

How can doctors tell if I have a heart attack?

Doctors do tests, such as:

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

Angioplasty
VIDEO

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

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 illicit drugs—these can be hard to stop, so talk to your doctor or a counselor about how to get help

Take your medicines correctly

Drugs Mentioned In This Article

Generic Name Select Brand Names
Anacin Adult Low Strength, Aspergum, Aspir-Low, Aspirtab , Aspir-Trin , Bayer Advanced Aspirin, Bayer Aspirin, Bayer Aspirin Extra Strength, Bayer Aspirin Plus, Bayer Aspirin Regimen, Bayer Children's Aspirin, Bayer Extra Strength, Bayer Extra Strength Plus, Bayer Genuine Aspirin, Bayer Low Dose Aspirin Regimen, Bayer Womens Aspirin , BeneHealth Aspirin, Bufferin, Bufferin Extra Strength, Bufferin Low Dose, DURLAZA, Easprin , Ecotrin, Ecotrin Low Strength, Genacote, Halfprin, MiniPrin, St. Joseph Adult Low Strength, St. Joseph Aspirin, VAZALORE, Zero Order Release Aspirin, ZORprin
NOTE: This is the Consumer Version. DOCTORS: VIEW PROFESSIONAL VERSION
VIEW PROFESSIONAL VERSION
quiz link

Test your knowledge

Take a Quiz!
iOS ANDROID
iOS ANDROID
iOS ANDROID
TOP