What is unstable angina?

Angina is another word for heart-related chest pain. You may also feel pain in other parts of your body, such as:

  • shoulders
  • neck
  • back
  • arms

The pain is due to inadequate blood supply to your heart muscle, which deprives your heart of oxygen.

There are two types of angina: stable and unstable.

Stable angina occurs predictably. It happens when you exert yourself physically or feel considerable stress. Stable angina doesn’t typically change in frequency and it doesn’t worsen over time.

Unstable angina is chest pain that occurs at rest or with exertion or stress. The pain worsens in frequency and severity. Unstable angina means that blockages in the arteries supplying your heart with blood and oxygen have reached a critical level.

An attack of unstable angina is an emergency and you should seek immediate medical treatment. If left untreated, unstable angina can lead to heart attack, heart failure, or arrhythmias (irregular heart rhythms). These can be life-threatening conditions.

The principal cause of unstable angina is coronary heart disease caused by a buildup of plaque along the walls of your arteries. The plaque causes your arteries to narrow and become rigid. This reduces the blood flow to your heart muscle. When the heart muscle doesn’t have enough blood and oxygen, you feel chest pain.

Risk factors for coronary heart disease include:

Men 45 years and older and women 55 years and older are more likely to experience unstable angina.

The main symptom of angina is chest discomfort or pain. The sensation can vary depending on the person.

Angina symptoms include:

  • chest pain that feels crushing, pressure-like, squeezing, or sharp
  • pain that radiates to your upper extremities (usually on the left side) or back
  • nausea
  • anxiety
  • sweating
  • shortness of breath
  • dizziness
  • unexplained fatigue

It’s possible for stable angina to progress to unstable angina. If you have stable angina, be aware of any chest pains you feel even when at rest. Also watch for chest pains that last longer than they typically do or that simply feel different to you. If you take nitroglycerin, a medication that enhances blood flow, for relief during a stable angina attack, you may find the medicine doesn’t work during an unstable angina attack.

You doctor will perform a physical exam that includes checking your blood pressure. They may use other tests to confirm unstable angina, such as:

  • blood tests, to check for creatine kinase and cardiac biomarkers (troponin) that leak from your heart muscle if it’s been damaged
  • electrocardiogram, to see patterns in your heartbeats that may indicate reduced blood flow
  • echocardiography, to produce images of your heart that reveal evidence of blood flow problems
  • stress tests, to cause your heart to work harder and make angina easier to detect
  • computed tomography angiography
  • coronary angiography and heart catheterization, to study the health and caliber of your arteries

Because coronary angiography helps your doctor visualize any artery narrowing and blockages, it’s one of the most common tests they use to diagnose unstable angina.

Treatment for unstable angina depends on the severity of your condition.


One of the first treatments your doctor may recommend is a blood thinner, such as aspirin, heparin, or clopidogrel. When your blood isn’t as thick, it can flow more freely through your arteries.

may use other medications to reduce angina symptoms, including drugs that reduce:

  • blood pressure
  • cholesterol levels
  • anxiety
  • arrhythmia symptoms


If you have a blockage or severe narrowing in an artery, your doctor may recommend more invasive procedures. These include angioplasty, where they open up an artery that was previously blocked. Your doctor also may insert a small tube known as a stent to keep your artery open.

In severe instances, you may need heart bypass surgery. This procedure reroutes blood flow away from a blocked artery to help improve blood flow to your heart.

Lifestyle changes

No matter the severity of your condition, you may need to change your long-term lifestyle. Lifestyle changes that can improve your heart health include:

All of these changes can lessen your chance of an angina attack and reduce your risk of heart attack. Talk to your doctor about appropriate changes to your lifestyle, including a healthy diet and exercise routine.

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Nonmedical self-care options include taking steps to lose weight, giving up tobacco use, and exercising more regularly. Working toward a healthier lifestyle can improve your heart health and reduce your risk of future unstable angina episodes.