heart during angina

Figure 1. Angina is a sign that the heart muscle is not receiving suffiicient oygenated blood.

normal and narrowed arteries

Figure 2. An artery with normal blood flow (A) and an artery containing plaque buildup (B). Credit: National Institutes of Health.

Angina, also called angina pectoris, is chest pain or discomfort that occurs when the muscle of the heart (see cardiac muscle) doesn't get enough blood (Fig 1). It may feel like pressure or a squeezing pain in the chest. The pain may also occur in the shoulders, arms, neck, jaw, or back. It may also feel like indigestion.


Angina is a symptom of coronary artery disease (CAD), the most common type of heart disease. CAD occurs when plaque builds up in the coronary arteries (Fig 2). This buildup of plaque is called atherosclerosis. As plaque builds up, the coronary arteries become narrow and stiff. Blood flow to the heart is reduced, which decreases the oxygen supply to the heart muscle.


Types of angina

The three types of angina are stable, unstable, and variant (Prinzmetal's). It is very important to know the differences among the types.


  • Stable angina. Stable angina is the most common type. It occurs when the heart is working harder than usual.
  •      There is a regular pattern to stable angina. After several episodes, you learn to recognize the pattern and can predict when it will occur.
         The pain usually goes away in a few minutes after you rest or take your angina medicine.
         Stable angina is not a heart attack but makes it more likely that you will have a heart attack in the future.

  • Unstable angina. Unstable angina is a very dangerous condition that requires emergency treatment. It is a sign that a heart attack could occur soon. Unlike stable angina, it does not follow a pattern. It can occur without physical exertion and is not relieved by rest or medicine.

  • Variant angina. Variant angina is rare. It usually occurs at rest. The pain can be severe and usually occurs between midnight and early morning. It is relieved by medicine.

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



    Angina is caused by reduced blood flow to an area of the heart. This is most often due to coronary artery disease (CAD). Sometimes, other types of heart disease or uncontrolled high blood pressure can cause angina.


    In CAD, the coronary arteries that carry oxygen-rich blood to the heart muscle are narrowed due to the buildup of fatty deposits called plaque. This is called atherosclerosis. Some plaque is hard and stable and leads to narrowed and hardened arteries. Other plaque is soft and is more likely to break open and cause blood clots. The buildup of plaque on the inner walls of the arteries can cause angina in two ways:


  • By narrowing the artery to the point where the flow of blood is greatly reduced
  • By forming blood clots that partially or totally block the artery

    Stable angina

    Physical exertion is the most common cause of pain and discomfort from stable angina. Severely narrowed arteries may allow enough blood to reach the heart when the demand for oxygen is low (such as when you are sitting). But with exertion, like walking up a hill or climbing stairs, the heart works harder and needs more oxygen. Other causes include:


  • Emotional stress
  • Exposure to very hot or cold temperature
  • Heavy meals
  • Smoking

    Unstable angina

    Unstable angina is caused by blood clots that partially or totally block an artery. If plaque in an artery ruptures or breaks open, blood clots may form. This creates a larger blockage. The clot may grow large enough to completely block the artery and cause a heart attack. Blood clots may form, partly dissolve, and later form again. Chest pain can occur each time a clot blocks an artery.


    Variant angina

    Variant angina is caused by a spasm in a coronary artery. The spasm causes the walls of the artery to tighten. This narrows the artery, causing the blood flow to the heart to slow or stop. Variant angina may occur in people with or without CAD. Other causes of spasms in the arteries that supply the heart with blood are:


  • Exposure to cold
  • Emotional stress
  • Medications (vasoconstricting) that constrict or narrow blood vessels
  • Cigarette smoking
  • Cocaine use

    Who is at risk?

    More than 6 million people in the United States have angina.


    People with coronary artery disease or who have had a heart attack are more likely to have angina.


    Unstable angina occurs more often in older adults.


    Variant angina is rare. It accounts for only about 2% of cases of angina. People with variant angina are often younger than those with other forms of angina.


    Signs and symptoms

    Pain and discomfort are the main symptoms of angina. These symptoms


  • Are often described as pressure, squeezing, burning, or tightness in the chest
  • Usually start in the chest behind the breastbone
  • May also occur in the arms, shoulders, neck, jaw, throat, or back
  • May feel like indigestion

    Some people say that angina discomfort is hard to describe or that they can't tell exactly where the pain is coming from. Symptoms such as nausea, fatigue, shortness of breath, sweating, light-headedness, or weakness may also occur.


    Symptoms vary based on the type of angina.


    Stable angina

    The pain or discomfort:


  • Occurs when the heart must work harder, usually during physical exertion
  • Is expected, and episodes of pain tend to be alike
  • Usually lasts a short time (5 min or less)
  • Is relieved by rest or angina medicine
  • May feel like gas or indigestion
  • May feel like chest pain that spreads to the arms, back, or other areas

    Unstable angina

    The pain or discomfort:


  • Often occurs at rest, while sleeping at night, or with little physical exertion
  • Is unexpected
  • Is more severe and lasts longer (as long as 30 minutes) than episodes of stable angina
  • Is usually not relieved with rest or angina medicine
  • May get continuously worse
  • May signal that a heart attack will happen soon

    Variant angina

    The pain or discomfort:


  • Usually occurs at rest and during the night or early morning hours
  • Tends to be severe
  • Is relieved by angina medicine

    Chest pain that lasts longer than a few minutes and is not relieved by rest or angina medicine may mean you are having – or are about to have – a heart attack.



    To find out if you have angina, your doctor will:


  • Do a physical exam
  • Ask about your symptoms
  • Ask about your risk factors and your family history of coronary artery disease (CAD) or other heart disease

    Sometimes, your doctor can diagnose angina by noting your symptoms and how they occur. Your doctor may order one or more tests to help make a diagnosis of angina. The tests your doctor may order include:


  • Electrocardiogram (ECG or EKG). This test measures the rate and regularity of your heartbeat. Some people with angina have a normal EKG.

  • Stress test. Some heart problems are easier to diagnose when your heart is working harder and beating faster than when it's at rest. During stress testing, you exercise (or are given medicine if you are unable to exercise) to make your heart work harder and beat faster while heart tests are performed.


    During exercise stress testing, your blood pressure and EKG readings are monitored while you walk or run on a treadmill or pedal a bicycle. Other heart tests, such as nuclear heart scan or echocardiography (see below for more information on these tests), also can be done at the same time. These would be ordered if your doctor needs more information than the exercise stress test can provide about how well your heart is working.


    If you are unable to exercise, a medicine can be injected through an intravenous line (IV) into your bloodstream to make your heart work harder and beat faster, as if you are exercising on a treadmill or bicycle. Nuclear heart scanning or echocardiography is then usually done.


    During nuclear heart scanning, radioactive tracer is injected into your bloodstream, and a special camera shows the flow of blood through your heart and arteries. Echocardiography uses sound waves to show blood flow through the chambers and valves of your heart and to show the strength of your heart muscle.


    Your doctor also may order two newer tests along with stress testing if more information is needed about how well your heart works. These new tests are magnetic resonance imaging (MRI) and positron emission tomography (PET) scanning of the heart. MRI shows detailed images of the structures and beating of your heart, which may help your doctor better assess if parts of your heart are weak or damaged. PET scanning shows the level of chemical activity in different areas of your heart. This can help your doctor determine if enough blood is flowing to the areas of your heart. A PET scan can show decreased blood flow caused by disease or damaged muscles that may not be detected by other scanning methods.

  • Chest X-ray. A chest X-ray takes a picture of the organs and structures inside your chest. These include your heart, lungs, and blood vessels.

  • Nuclear heart scan. This test provides your doctor with moving pictures of the blood passing through your heart's chambers and arteries and shows the level of blood flood to the heart muscle. A small amount of a radioactive tracer is injected into your bloodstream through a vein, usually in your arm. A special camera is placed in front of your chest to show where the tracer lights up in healthy heart muscle and where it doesn't light up (in heart muscle that has been damaged or has a blocked artery).


    There are different types of nuclear heart scans. Most scans have two phases – taking pictures of the heart at rest and while it is beating faster (called a stress test), although sometimes only a rest scan is done. Many heart problems show up more clearly when your heart is stressed than when it is at rest. By comparing the nuclear heart scan of your heart at rest to your heart at "stress," your doctor can determine if your heart is functioning normally or not.

  • Echocardiogram. This test uses sound waves to create a moving picture of your heart. Echocardiogram provides information about the size and shape of your heart and how well your heart chambers and valves are functioning. The test also can identify areas of poor blood flow to the heart, areas of heart muscle that are not contracting normally, and previous injury to the heart muscle caused by poor blood flow. There are several different types of echocardiograms, including a stress echocardiogram. During this test, an echocardiogram is done both before and after your heart is stressed either by having you exercise or by injecting a medicine into your bloodstream that makes your heart beat faster and work harder. A stress echocardiogram is usually done to find out if you have decreased blood flow to your heart (coronary artery disease).

  • Cardiac catheterization. A thin flexible tube (catheter) is passed through an artery in the groin (upper leg) or arm to reach the coronary arteries. Your doctor can determine pressure and blood flow in the heart's chambers, collect blood samples from the heart, and examine the arteries of the heart by X-ray.

  • Coronary angiography. This test is done during cardiac catheterization. A dye that can be seen by X-ray is injected through the catheter into the coronary arteries. Your doctor can see the flow of blood through your heart and the location of blockages.

    Your doctor may also order blood tests, such as:


  • A fasting lipoprotein profile to check your cholesterol levels.
  • Fasting glucose test to check your blood sugar level.
  • C-reactive protein (CRP) test. This blood test measures CRP, a protein in the blood that shows the presence of inflammation. Inflammation is the body's response to injury. High levels of CRP may be a risk factor for CAD.
  • A test to check for low hemoglobin in your blood. Hemoglobin is the part of red blood cells that carries oxygen to all parts of your body.


    Treatment for angina includes lifestyle changes, medicine, special procedures, and cardiac rehabilitation. The main goals of treatment are to:


  • Reduce the frequency and severity of symptoms
  • Prevent or lower the risk of heart attack and death

    Lifestyle changes and medicine may be the only treatments needed if your symptoms are mild and are not getting worse. Unstable angina is an emergency condition that requires treatment in the hospital.


    Lifestyle changes

    The first thing that you need to do is change your living habits to avoid bringing on an episode of angina.


  • Slow down or take rest breaks, if angina comes on with exertion.
  • Avoid large meals and rich foods that leave you feeling stuffed, if angina comes on after a heavy meal.
  • Try to avoid situations that make you upset or stressed, if angina comes on with stress. Learn techniques to handle stress that can't be avoided.

    You can also make other lifestyle changes, for example:


  • Eat a healthy diet to prevent or reduce high blood pressure, high blood cholesterol, and overweight or obesity
  • Quit smoking, If you smoke
  • Be physically active, as directed by your doctor
  • Lose weight, if you are overweight or obese.
  • Follow your doctor's orders and take all medicines as directed, especially if you have diabetes


    Nitrates are the most commonly used medicines to treat angina. Fast-acting preparations are taken when angina occurs or is expected to occur. Nitrates relax and widen blood vessels, allowing more blood to flow to the heart while reducing its workload.


    You can use nitrates in different forms to:


  • Relieve an episode that is occurring by using the medicine when the pain begins
  • Prevent an episode from occurring by using the medicine just before pain or discomfort is expected to occur
  • Reduce the number of episodes that occur by using the medicine regularly on a long-term basis
  • Nitroglycerin is the most commonly used nitrate for angina. Nitroglycerin that dissolves under your tongue or between your cheeks and gum is used to relieve an angina episode. Nitroglycerin in the form of pills and skin patches is used to prevent attacks of angina. These forms of nitroglycerin act too slowly to relieve pain during an angina attack.

  • Beta blockers slow the heart rate and lower blood pressure. They can delay or prevent the onset of angina.

  • Calcium channel blockers relax blood vessels so that more blood flows to the heart, reducing pain from angina. Calcium channel blockers also lower blood pressure.

  • ACE inhibitors (angiotensin-converting enzyme inhibitors) lower blood pressure and reduce the strain on the heart. They also reduce the risk of a future heart attack and heart failure.

    People who have angina may also use:


  • Medicines to lower cholesterol levels.

  • Medicines to lower high blood pressure.

  • Oral antiplatelet medicines (such as aspirin and clopidigrel), taken daily, to stop platelets from clumping together to form blood clots.

    Platelets are small blood cells that circulate through your blood vessels and help stop bleeding by sticking together to seal small cuts or breaks in tiny blood vessels. Antiplatelet medicines may not be appropriate for some people because they increase the risk of bleeding. Discuss the benefits and risks with your doctor before starting therapy with aspirin or the other antiplatelet medicines.

  • Glycoprotein IIb-IIIa inhibitors are potent antiplatelet medicines that prevent clots from forming in your arteries. They are given intravenously in hospitals for the treatment of angina or during and after angioplasty.

  • Anticoagulants to prevent clots from forming in your arteries and blocking blood flow.

    Special procedures

    When medicines and other treatments do not control angina, special (invasive) procedures may be needed. Two commonly used procedures are:


  • Angioplasty. This procedure opens blocked or narrowed coronary arteries. It can improve blood flow to your heart, relieve chest pain, and possibly prevent a heart attack. Sometimes a stent is placed in the artery to keep it propped open after the procedure.

  • Coronary artery bypass grafting. This procedure uses arteries or veins from other areas in your body to bypass your blocked coronary arteries. Bypass surgery improves blood flow to your heart, relieves chest pain, and can prevent a heart attack.

    Cardiac rehabilitation

    Your doctor may prescribe cardiac rehabilitation (rehab) for angina or after bypass surgery, angioplasty, or a heart attack.


    The cardiac rehab team may include:


  • Doctors
  • Your family doctor
  • A heart specialist
  • A surgeon
  • Nurses
  • Exercise specialists
  • Physical therapists and occupational therapists
  • Dietitians
  • Psychologists or other behavior therapists

    Rehab has two parts:


  • Exercise training. This helps you learn how to exercise safely, strengthen your muscles, and improve your stamina. Your exercise plan will be based on your individual ability, needs, and interests.

  • Education, counseling, and training. This helps you understand your heart condition and find ways to reduce your risk of future heart problems. The cardiac rehab team will help you learn how to cope with the stress of adjusting to a new lifestyle and to deal with your fears about the future.


    You can prevent or lower your risk for heart disease and angina by making lifestyle changes and getting treatment for related conditions.


    Make lifestyle changes

    You can prevent or lower your risk for angina and heart disease by making healthy lifestyle choices:


  • Eat a healthy diet to prevent or reduce high blood pressure, high blood cholesterol, and obesity.
  • Quit smoking, if you smoke
  • Be physically active, as directed by your doctor
  • Lose weight, if you are overweight or obese

    Treat related conditions

    In addition to making lifestyle changes, you can help prevent angina and heart disease by treating related conditions, such as:


  • High blood cholesterol. If you have high cholesterol, follow your doctor's advice about lowering it. Take medications to lower your cholesterol as directed.

  • High blood pressure. If you have high blood pressure, follow your doctor's advice about keeping your blood pressure under control. Take blood pressure medications as directed.

  • Diabetes (high blood sugar). If you have diabetes, follow your doctor's advice about keeping your blood sugar levels under control. Take medicines as directed.

  • Overweight or obesity. If you are overweight or obese, talk to your doctor about how to lose weight safely.

    Living with angina

    Angina is not a heart attack, but it does mean that you are at greater risk of having a heart attack than someone who does not have angina. The risk is even higher if you have unstable angina. For these reasons, it is important that you know:


  • The usual pattern of your angina, if you have it on a regular basis
  • About your medicine
  • How to control your angina
  • The limits of your physical activity
  • How and when to seek medical attention

    Know the pattern of your angina

    Stable angina usually occurs in a pattern. You should know:


  • What causes the pain to occur
  • What it feels like
  • How long it usually lasts
  • Whether it is relieved by rest or medicine

    After several episodes, you will learn to recognize when you are having angina. It is important for you to notice if the pattern starts to change. Changes in the pattern to look for may include:


  • Occurring more often
  • Lasting longer
  • Being more severe
  • Occurring without exertion
  • Not going away with rest or medicine

    These changes in the pattern may be a sign that your symptoms are getting worse or becoming unstable. You should seek medical attention. Unstable angina suggests that you are at high risk for a heart attack very soon.


    Know your medicines

    You should know what medicines you are taking, the purpose of each, how and when to take them, and possible side effects. It is very important that you know exactly when and how to take fast-acting nitroglycerin or other nitrates to relieve chest pain. They should be taken:


  • Immediately when pain begins or before stressful activity
  • Three times spaced 5 minutes apart if pain does not go away
  • Always sit down before taking nitroglycerin.

    Long-acting nitrate preparations should be used regularly as prescribed by your doctor.


    Men with impotence (erectile dysfunction) who take sildenafil (Viagra) should talk with their doctor. Taking sildenafil and nitroglycerin or other nitrates within 24 hours of each other can cause serious problems.


    Ask your doctor about your other medicines. Also, see the Treatment section to read descriptions of the medicines that you are taking.


    Know how to control your angina

    After several episodes, you will know the level of activity, stress, and other things that can bring on your angina. By knowing this, you can take steps to prevent or lessen the severity of episodes.


  • Physical exertion. Know what level of activity brings on your angina and try to stop and rest before chest pain starts. For example, if walking up a flight of stairs leads to chest pain, then stop halfway and rest before continuing. When chest pain occurs during exertion, stop and rest or take your angina medicine. The pain should go away in a few minutes. If the pain does not go away or lasts longer than usual, get emergency care.

  • Emotional stress. Anger, arguing, and worrying are examples of emotional stress that can bring on an angina episode. Try to avoid or limit exposure to situations that cause these emotions. Exercise and relaxation can help relieve stress. Alcohol and drug use play a part in causing stress and do not relieve it. If stress is a problem for you, talk with your doctor about getting counseling to help you deal with stress.

  • Eating large meals. If this leads to chest pain, eat smaller meals. Also, avoid eating rich foods.

    Know the limits of your physical activity

    Most people with stable angina can continue their normal activities. This includes work, hobbies, and sexual relations. However, if you engage in very strenuous activity or have a stressful job, you may need to discuss this with your doctor.


    Know how and when to seek medical attention

    If you have angina, you are at high risk of having a heart attack. Therefore, it is very important that you and your family know how and when to seek medical attention. Talk to your doctor about making an emergency action plan. The plan should include:


  • The signs and symptoms of a heart attack
  • Instructions for the prompt use of aspirin and nitroglycerin
  • How to access emergency medical services in your community
  • The location of the nearest hospital that offers 24-hour emergency heart care

    Be sure to discuss your emergency plan with your family members. Take action quickly if your chest pain becomes severe, lasts longer, or is not relieved by rest or medicine.


    Sometimes, it may be difficult to tell the difference between unstable angina and a heart attack. Most heart attack victims wait 2 hours or more after their symptoms begin before they seek medical help. This delay can result in death or lasting heart damage.