Difference Between Stable and Unstable Angina

Angina is the chest pain caused due to an insufficient supply of oxygen to the heart muscles. It is characterized by a squeezing tightness in the chest.

It is not a disease but a symptom of any underlying heart disease. It is caused due to the narrowing or blocking of anyone coronary artery. Stable and unstable angina are two types of angina.

Stable vs Unstable Angina

The main difference between stable and unstable angina is that stable angina occurs when the heart is pumping blood at a high rate. This occurs during running or exercising. Unstable angina is caused due to the presence of a block in the blood vessel supplying blood to the heart. This blockage is caused by a condition called atherosclerosis.

Stable vs Unstable Angina

Stable angina occurs when a person does heavy physical activities like swimming, running, etc, Since, it accompanies physical exercise it is predictable. It lasts for about 5 minutes.

Resting or taking medications can relieve the symptoms. Stress can also cause angina. Stable angina is also called angina pectoris.

The pattern of occurrence of stable angina can be tracked.

Unstable angina is characterized by chest pain that occurs during rest. It is not caused by stress or physical activity.

The frequency of pain worsens with time. Unstable angina indicates that the blockage in a blood vessel supplying the heart has reached a critical stage.

Unstable angina is severe and needs medical care.

Comparison Table Between Stable and Unstable Angina

Parameters of Comparison Stable AnginaUnstable Angina
Chest PainOccurs during emotional stress or physical activitiesOccurs during rest.
PredictabilityStable angina is PredictableUnstable angina is not predictable
DiagnosisElectrocardiogram, Angiography, stress test, Cholesterol and CRP protein tests.Electrocardiogram, echocardiography, stress test, creatine kinase test, cardiac biomarker test. Stress tests, coronary angiography, and catheterization are done
TreatmentLifestyle changes and Nitroglycerine medication.Emergency treatment by a specialized cardiologist
SeverityIt is not usually severe but if untreated can lead to unstable anginaCan lead to myocardial infarction and cardiac arrest
CauseCaused by low oxygen supply to heart muscles during exercise and workNarrowing of an artery due to plaque deposition

What is Stable Angina?

Stable angina or Angina pectoris is the most common angina. It occurs while doing exercise or any other harder activities so, the pattern of occurrence can be tracked and it can be prevented.

It is less serious than unstable angina but, painful. Though it is not serious it may indicate an underlying disease.

So it requires medical attention.

The pain feels like a heavyweight resting on your chest. It is usually felt in the middle of the chest and spreads to the neck and shoulders.

Other symptoms include nausea, dizziness, fatigue, shortness of breath, anxiety, and sweating.

The risk factors for stable angina are obesity, heart disease, high cholesterol or Blood Pressure, smoking, diabetes, and lack of exercise.

Diagnosis is done by Electrocardiogram and Angiography. These tests are run to ensure the proper functioning of the heart and to detect the presence of any blocks.

Cholesterol and CRP protein levels are also tested. Doctors advise their patients to take a stress test to find out if angina has been caused by stress.

Treatment of stable angina consists of several lifestyle changes, medications and surgery if required. Reducing physical activity can also help to manage the symptoms.

Exercising regularly, eating a healthy diet that consists of fresh vegetables, fruits, and whole grains, and quitting smoking are some of the lifestyle changes one can make to avoid stable angina.

What is Unstable Angina?

Unstable angina is a serious condition and needs immediate medical care.

The most common cause of unstable angina is coronary artery disease which is caused by the deposition of plaques along the walls of the artery.

This plaque buildup eventually narrows the artery and blocks the flow of blood. Lack of blood flow causes a decrease in the supply of oxygen to the heart which leads to chest pain.

Risk factors of Unstable angina include obesity, diabetes, family history of heart disease, high blood pressure, high LDL, low HDL, and using tobacco.

Men are more prone to unstable angina. Men, more than 45 years, and women more than 55 years are susceptible to unstable angina.

Symptoms include chest pain that spreads to the left arm and back. Nausea, anxiety, sweating, dizziness, shortness of breath, and fatigue.

Electrocardiograms and echocardiography are used to diagnose unstable angina. A blood test is done to check for creatine kinase and cardiac biomarkers.

Stress tests, coronary angiography, and catheterization are also done.

Unstable angina is treated with blood thinners like heparin, aspirin, and clopidogrel. Surgery is also done in severe cases to remove the block.

A stent is inserted into the blocked artery to keep it open.

Lifestyle changes like eating a healthier diet, exercising, lowering stress by meditation, losing weight, and quitting smoking can lessen the chances of unstable angina.

Main Differences Between Stable and Unstable Angina

  1. Stable angina is caused due to heavy physical activity. But, Unstable angina is caused due to blocks in the arteries supplying blood to the heart muscles.
  2. Stable angina usually does not retain for a long time and is not serious. Unstable angina may retain for a long period and get severe.
  3. Stable angina is caused after exercise or any other heavy work. Whereas, unstable angina occurs during rest.
  4. Stable angina is predictable but, unstable angina is not predictable.
  5. Nitroglycerin is used to treat stable angina. It is taken in the form of a pill which is kept under the tongue. Treatment for unstable angina should be given by doctors in emergency care. Blood thinners can be taken.
  6. Stable angina can be prevented or cured by not getting involved in hard physical activities. While unstable angina can be treated by a surgery in which a catheter is inserted into the blocked artery and inflated to keep it open.
Difference Between Stable and Unstable Angina


Stable angina may occur due to stress but, unstable angina is severe and if untreated can lead to death. Though the chest pain is similar in both cases unstable angina lasts longer than stable angina.

Stable angina can eventually develop into unstable angina if untreated. Nitroglycerin medication taken to promote blood flow for stable angina does not work for unstable angina.

Men have a high risk of angina. Women are protected by the natural estrogen hormone. Lifestyle changes can help to prevent angina attacks.

Giving up smoking, exercising regularly, and eating a balanced healthy diet including fibers and good lipids are ideal. Simple exercise like walking can improve health.

Keeping cholesterol and blood pressure levels at normal is also a good way to prevent angina.


  1. https://www.ahajournals.org/doi/abs/10.1161/01.CIR.51.6.1059
  2. https://academic.oup.com/eurheartj/article-abstract/19/1/80/524520

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