What Is Angina?

Angina (an-JI-nuh or AN-juh-nuh) is chest pain or discomfort that occurs when an area of your heart muscle doesn't get enough oxygen-rich blood. Angina may feel like pressure or squeezing in your chest. The pain also may occur in your shoulders, arms, neck, jaw, or back. It can feel like indigestion.

Angina itself isn't a disease. Rather, it's a symptom of an underlying heart problem. Angina is usually a symptom of coronary artery disease (CAD), the most common type of heart disease.

CAD occurs when a fatty material called plaque (plak) builds up on the inner walls of the coronary arteries. These arteries carry oxygen-rich blood to your heart. When plaque builds up in the arteries, the condition is called atherosclerosis (ATH-er-o-skler-O-sis).
Figure A shows a normal artery with normal blood flow. Figure B shows an artery containing plaque buildup.

Plaque causes the coronary arteries to become narrow and stiff. The flow of oxygen-rich blood to the heart muscle is reduced. This causes pain and can lead to a heart attack.
Types of Angina

The three types of angina are stable, unstable, and variant (Prinzmetal's). Knowing how the types are different is important. This is because they have different symptoms and require different treatment.
Stable Angina

Stable angina is the most common type. It occurs when the heart is working harder than usual. Stable angina has a regular pattern. If you know you have stable angina, you can learn to recognize the pattern and predict when the pain will occur.

The pain usually goes away in a few minutes after you rest or take your angina medicine.

Stable angina isn't a heart attack, but it makes a heart attack more likely in the future.
Unstable Angina

Unstable angina doesn't follow a pattern. It can occur with or without physical exertion and isn't relieved by rest or medicine.

Unstable angina is very dangerous and needs emergency treatment. It's a sign that a heart attack may happen soon.
Variant (Prinzmetal's) Angina

Variant angina is rare. It usually occurs while you're at rest. The pain can be severe. It usually happens between midnight and early morning. This type of angina is relieved by medicine.
Overview

It's thought that nearly 7 million people in the United States suffer from angina. About 400,000 patients go to their doctors with new cases of angina every year.

Angina occurs equally in men and women. It can be a sign of heart disease, even when initial tests don't show evidence of CAD.

Not all chest pain or discomfort is angina. A heart attack, lung problems (such as an infection or a blood clot), heartburn, or a panic attack also can cause chest pain or discomfort. All chest pain should be checked by a doctor.