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Unstable Angina Pectoris

Written by Ada’s Medical Knowledge Team

Updated on

What is unstable angina pectoris?

Unstable angina, also known as unstable angina pectoris, is a medical emergency with sudden chest pain or tightness that worsens over a short period of time.

Although it is not a heart attack, the symptoms are very similar, and is a warning that a person may have a heart attack in the near future. The symptoms are usually not predictable and often do not improve with rest. It occurs when the flow of blood and oxygen to the heart is reduced. Hardening and narrowing of the heart blood vessels due to atherosclerosis is the most common cause of stable angina.

It is more common in older adults, smokers, and people with high blood pressure or high blood cholesterol levels.

Treatment involves short term treatments to reduce pain and relax the blood vessels of the heart, and long-term medications and lifestyle changes to reduce the chance of having a heart attack in the future. With good management, many people learn to manage their symptoms. However, without treatment, the underlying cause may get worse and eventually cause a heart attack.


Angina occurs when the heart is temporarily not getting enough oxygen. This occurs when narrowing of the blood vessels of the heart make it difficult for the heart to get extra blood when it needs to work harder (for example, when doing exercise). Unstable angina occurs when the vessels become very narrow. This condition is similar to a heart attack, and is a warning sign that a person may have a heart attack in the future. The most common cause is atherosclerosis, which is the narrowing and formation of collections in blood vessels over time. Older people and people with medical conditions such as diabetes, high blood pressure, and high blood cholesterol are more likely to have this condition. Smoking also increases the risk of developing angina.


The typical symptom of angina is a chest pressure or pain that radiates to the left arm, back, jaw or neck.

There may also be:

  • sweating
  • shortness of breath
  • nausea and vomiting

The symptoms of unstable angina often come on quickly, and may have no predictable trigger. Some people experience symptoms while resting. Some people find that using GTN spray or tablets (glyceryl trinitrate) don't help to improve their symptoms.


Diagnosis is usually made based on the symptoms, a physical examination and an electrocardiogram (ECG). The best test to look for blockages in the blood vessels is coronary angiography. This involves injecting dye into the blood vessels of the heart and taking X-rays to see any blockages. A blood test will be done to exclude heart attack. Other tests may include an ultrasound of the heart (echocardiography), cholesterol levels and blood sugar levels.

Treatment of angine pectoris

Treatment of unstable angina involves short-term measures to reduce pain and long-term measures to reduce the risk of a heart attack. People with chest pain should take GTN (spray, tablet or capsule) under the tongue. If the pain continues or gets worse, the person needs to urgently go to the emergency department.

If there are warning signs that a person is at very high risk of a heart attack, emergency angiography could be needed, and a stent (a small wire tube) can be placed to open up any blockages in the blood vessels. Long-term treatment for unstable angina often involves medications to thin the blood, to control blood pressure and to reduce cholesterol levels.

An exercise program (cardiac rehabilitation) may be helpful to improve heart function. Eventually, a procedure to open the narrowed heart blood vessels with a stent, or even bypass surgery may be needed to prevent a heart attack.


Eating a healthy diet, regular exercise, maintaining a healthy weight and giving up smoking can help to prevent developing blockages in the blood vessels of the heart. Cholesterol levels, blood pressure and blood sugar should be well controlled in order to prevent this condition.

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