What is Unstable Angina?

Instructor: Kristin Lundsten

Kristin has taught pediatric and psychiatric nursing and has a master's degree in nuring education

This lesson will define unstable angina and some of the possible causes. We will also explore some of the common symptoms associated and review some of the more common up-to-date treatments.

Pain in Two Scenarios

Scenario 1

After a long day in the yard raking, bagging leaves, and moving fallen tree branches, you finally sit back to enjoy a relaxing evening on your couch. Before long, you notice an ache in your chest. You resume your television watching without concern, attributing the aches and pains to a long day of exertion that is not typical to your daily routine.

Scenario 2

After a long day of relaxing around the house, you move to your bed to wrap up the evening with a book. After about 20 minutes, you begin to notice an aching in your chest. You put down the book and sit up in your bed, worried.

What are the main differences in these two scenarios? Well, in Scenario 1 there is an explanation for the discomfort, as the individual spent a long day working in the yard. In Scenario 2, however, there seems to be no explanation for the onset of the discomfort, and therefore there is reason for alarm.

This helps to provide a context for the difference between angina and unstable angina.


Angina is a clinical condition or symptom characterized as crushing chest pain. Angina typically occurs during or after a period of physical exertion or emotional distress. People who live with angina can associate the occurrence of symptoms to a particular trigger.

Unstable angina is when the crushing chest pain and other symptoms of angina occur at random or without reason, similar to the second scenario. Unstable angina may persist longer than angina. In addition, when treating angina with nitroglycerin (a fast-acting medication that relieves angina symptoms), unstable angina tends to not respond in the same manner as stable angina.


All variants of angina are caused by coronary artery disease, known as CAD, which occurs when the major blood vessels in the body become narrowed. This is caused by a buildup of a sticky substance called plaque, which consists of fat, cholesterol, and other substances that can narrow or even block the passageways to the heart.

Plaque buildup in the arteries

Think of those vessels as three-lane roadways with trucks transporting supplies of oxygen, nutrients, and blood to your heart. If two of the lanes were blocked, you'd have a traffic jam and distribution would falter. The blocked or narrowed blood vessel will not be able to transport the needed oxygen, blood, and nutrients to the heart as quickly or efficiently. This is angina and can lead to pain if you are physically active or in emotional distress.

However, if those arteries are blocked by a blood clot, it would be like a giant rock blocking the entire roadway. This is unstable angina, and can be extremely dangerous, leading to abnormal heart rhythms, heart attack, heart failure, or even death.


Regular angina can involve chest pain, as well as pain in the back, shoulders, arms, neck or jaw. Although chest pain or discomfort is a sign of both stable and unstable angina, there are some signs that are usually associated with unstable angina only. Some of these signs are:

  • Severe, sudden pain not associated with exertion
  • Shortness of breath
  • Tightness, burning, aching sensation in the chest that spreads to the necks, torso, or jaw.
  • Sweating
  • Medication not helping
  • Blood pressure drop

Risk Factors and Treatments

People with a history of high cholesterol, diabetes, obesity, smoking, lack of exercise, and high blood pressure are at higher risk for coronary artery disease and angina. People who are older seem to have a higher risk for unstable angina.

The best way to avoid unstable angina is to not get heart disease in the first place. Sometimes, heart disease is hereditary, but healthy lifestyle practices like exercise, good nutrition, and not smoking can decrease your chances of getting heart disease.

Unstable angina must be treated by finding the blockage itself. This is usually done by inserting a catheter in the arm or leg, feeding it through to the coronary arteries, then injecting a dye. X-rays will then be able to identify the area of the clot. In percutaneous coronary intervention (PCI), the surgeons might use a balloon to open the artery, and then possibly insert a stent, keeping that artery open for the future. They may instead perform coronary artery bypass graft surgery, where they take an artery from another part of the body and insert it near the blocked artery, to re-route blood to the heart.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create An Account