Overview

What is a heart attack?

A heart attack occurs when blood flow to the heart is blocked. Without blood and the oxygen it carries, part of the heart starts to die. A heart attack doesn't have to be deadly. Quick treatment can restore blood flow to the heart and save your life.

Your doctor might call a heart attack a myocardial infarction, or MI. Your doctor might also use the term acute coronary syndrome for your heart attack or unstable angina.

What is angina, and why is unstable angina a concern?

Angina (say "ANN-juh-nuh" or "ann-JY-nuh") is a type of chest pain or discomfort that occurs when there is not enough blood flow to the heart. Angina can be dangerous. So it is important to pay attention to your symptoms, know what is typical for you, learn how to control it, and know when to call for help.

Symptoms of angina include chest pain or pressure, or a strange feeling in the chest. Some people feel pain, pressure, or a strange feeling in the back, neck, jaw, or upper belly, or in one or both shoulders or arms.

There are two types of angina:

• Stable angina has a typical pattern. You can likely predict when it will happen. It happens when your heart is working harder and needs more oxygen, such as during exercise. Your symptoms go away when you rest.
• Unstable angina is unexpected, and resting or taking nitroglycerin may not help. Your doctor will probably diagnose unstable angina if you are having symptoms for the first time or if your symptoms are getting worse, lasting longer, happening more often, or happening at rest.

Unstable angina is a warning sign that a heart attack may happen soon, so it requires treatment right away. But if you have any symptoms of angina, see your doctor.

What causes a heart attack?

Heart attacks happen when blood flow to the heart is blocked. This usually occurs because fatty deposits called plaque have built up inside the coronary arteries, which supply blood to the heart. If a plaque breaks open, the body tries to fix it by forming a clot around it. The clot can block the artery, preventing the flow of blood and oxygen to the heart. See a picture of how plaque causes a heart attack.

This process of plaque buildup in the coronary arteries is called coronary artery disease, or CAD. In many people, plaque begins to form in childhood and gradually builds up over a lifetime. Plaque deposits may limit blood flow to the heart and cause angina. But too often, a heart attack is the first sign of CAD.