Angina is a syndrome (a collection of symptoms caused by an underlying health condition) that is caused when the supply of oxygen-rich blood to the heart becomes restricted.

The most common symptom of angina is chest pain, which is usually triggered by physical activity.

Most cases of angina are caused by atherosclerosis, which is a condition where the arteries become hardened and narrower, restricting the supply of blood. Risk factors for atherosclerosis include:

  • advanced age
  • smoking
  • obesity
  • a high-fat diet

Diseases that affect the normal flow of blood, such as atherosclerosis, are known as cardiovascular diseases (CVD).

Types of angina

The two main types of angina are stable angina and unstable angina.

Stable angina

In cases of stable angina, the symptoms usually develop gradually over time and follow a set pattern. For example, you may only experience symptoms when climbing stairs or if you are under a lot of stress.

Symptoms usually only last for a few minutes and can be improved by taking medication known as glyceryl trinitrate.

Stable angina is not life-threatening on its own. However, it is a serious warning sign that you have an increased risk of experiencing more serious conditions, such as a heart attack or stroke.

Unstable angina

In cases of unstable angina, the symptoms develop rapidly, can persist even at rest, and can last up to 30 minutes. The symptoms of unstable angina may also be resistant to treatment with glyceryl trinitrate.

You may experience symptoms of unstable angina after previously having symptoms of stable angina. The symptoms of unstable angina can also occur in people who do not have a previous history of stable angina.

Unstable angina should be regarded as a medical emergency because it is a sign that the function of your heart has suddenly and rapidly deteriorated, increasing your risk of having a heart attack or stroke.

Unstable angina can be treated with medication and surgery.

How common is angina?

Angina is a common syndrome, particularly among older people. For example, it is estimated that in Ireland about 14% of people over 65 have angina or have had a heart attack.


The outlook for stable angina is moderately good. It is estimated that each year, 1 in every 100 people with stable angina will experience a fatal heart attack or stroke. An estimated 0.5-2.6% of people will experience a non-fatal heart attack in any given year.

It should be stressed that it is possible to significantly lower your risk of having a fatal heart attack or stroke by making some simple lifestyle changes.

For example, if you are a smoker and obese, and you successfully quit smoking and achieve a healthy weight, you will reduce your risk factor significantly.

See the Prevention section above for more advice and information about making lifestyle changes.

The outlook for people with unstable angina can vary considerably, depending on a number of possible risk factors including:

  • age
  • whether you have a history of heart disease
  • whether you have high-blood pressure (hypertension)
  • whether you have a chronic condition, such as diabetes

Depending on these factors, the risk that a person will experience a heart attack in the first 14 days after the onset of symptoms can range from 2% to 16%.

Stable angina

The most common symptom of angina is a feeling of pain or discomfort in your chest. The pain can feel tight, dull or heavy and usually passes within a few minutes.

The pain can spread from your chest to your left arm, neck, jaw and back. It usually follows a period of physical activity or emotional stress. In some cases, the pain may also develop during cold weather or after eating a meal. Factors that can provoke the symptoms of angina are known as angina triggers.

Some people with angina may also experience symptoms of:

  • breathlessness
  • nausea
  • fatigue
  • dizziness
  • belching (burping)
  • restlessness

The onset of angina symptoms is sometimes called an angina attack.

Unstable angina

The symptoms of unstable angina are the same as those of stable angina, although they do not follow the usual pattern of symptoms. For example, the symptoms:

  • can develop without any angina triggers being present
  • can persist even when you are resting
  • can last longer than five minutes
  • may not respond to treatment with glyceryl trinitrate

If you think you are experiencing symptoms of unstable angina, dial 999 and ask for an ambulance.

If you know that you are not allergic to aspirin, and aspirin is easily available, chew an adult-size tablet while you are waiting for the ambulance to arrive. Aspirin helps to prevent blood clots and will reduce your risk of experiencing a heart attack or a stroke.

Stable angina

Like all the other organs and tissues in your body, your heart needs a constant supply of oxygen-rich blood to function normally.

Blood is supplied to the heart by two large blood vessels known as the left and right coronary arteries.

The most common cause of stable angina is the coronary arteries becoming narrow and hardened (atherosclerosis), which restricts the blood flow to the muscles of the heart.

Stable angina is essentially a supply and demand problem. When you are at rest, the muscles in your heart only require a modest supply of blood so you will not experience any symptoms.

When you are exercising or you are feeling stressed, the muscles in your heart work harder so the demand for blood increases. However, due to the narrowed coronary arteries, the necessary amount of blood is unable to reach the heart in time, so the demand for blood outstrips the supply, triggering the symptoms of angina.

Unstable angina

One of the underlying causes of atherosclerosis is a build-up of fatty deposits, known as plaques, in the arteries. These plaques can rupture (split). The ruptured plaques interfere with the normal flow of blood, which causes a blood clot to form.

A blood clot can quickly grow, blocking one of the coronary arteries and drastically reducing the supply of blood to the heart, triggering the symptoms of unstable angina.

Risk factors

Anything that causes the coronary arteries to narrow is a risk factor for both stable and unstable angina. For example:

  • high-fat diets and cholesterol
  • a lack of exercise, a poor diet and excess alcohol
  • smoking
  • high blood pressure (hypertension)
  • diabetes
  • age
  • family history

These individual risk factors can also often be inter-related. They are explained below in more detail.

High-fat diets and cholesterol

Cholesterol is a type of fat essential for the functioning of the body. It helps produce hormones, protects nerve endings and makes up cell membranes (the walls that protect individual cells). There are two main types of cholesterol:

  • Low density lipoprotein (LDL) is mostly made up of fat, plus a small amount of protein. It is this sort of cholesterol that can block your arteries, so it is often referred to as bad cholesterol.
  • High density lipoprotein (HDL) is mostly made up of protein, plus a small amount of fat. It is this type of cholesterol that can help to reduce a blockage in your arteries, so it is often referred to as good cholesterol.

Most of the cholesterol that our body needs is manufactured by our liver. However, if we eat foods that are high in saturated fat, it is broken down into LDL, or bad cholesterol.

Foods high in saturated fat include biscuits, cakes, bacon, sausages, processed meat, butter and cream.

Exercise, obesity and alcohol

A lack of exercise, being obese and drinking excessive amounts of alcohol can increase the levels of LDL cholesterol in your body.


If you smoke, it can damage the walls of your arteries. If your arteries are damaged by smoking, blood cells known as platelets will form at the site of the damage in an attempt to repair it. This can cause your arteries to narrow.

Smoking also decreases your blood's ability to carry oxygen around your body, which increases the chances of a blood clot occurring.

High blood pressure

If you have high blood pressure (hypertension) it will damage your arteries in the same way as cigarette smoke. Your arteries are designed to pump blood at a certain pressure. If that pressure is exceeded, the walls of the arteries will be damaged. High blood pressure can be caused by:

  • being overweight
  • drinking excessive amounts of alcohol
  • stress
  • smoking
  • a lack of exercise

For reasons that are not fully understood, high blood pressure is more common among people of Afro-Caribbean and south Asian (Indian, Pakistani and Bangladeshi) origin.

A tendency to develop high blood pressure also often runs in families. This is known as a genetic predisposition.


If you have diabetes that is poorly controlled, the excess amount of glucose in your blood can damage your artery walls.


Arteries tend to get narrower over time. Therefore, the older you are, the more likely it is that your arteries will have narrowed, increasing your risk of developing angina.

Family history

Heart disease can run in families, so if you have a first degree relative (mother, father, brother or sister) with a history of heart disease or angina, you have an increased risk of developing angina yourself.

Stable angina

Initial assessment

Your GP will probably start by asking you about the pattern of your symptoms, such as if you have noticed any particular triggers that could lead to the onset of symptoms.

They will then carry out a general assessment. This is to assess whether you have any signs and symptoms that could suggest you are at increased risk of developing atherosclerosis, which in turn, could lead to the symptoms of angina.

As part of the assessment you will be given:

  • blood tests to measure the amount of cholesterol in your blood, and glucose if you are diabetic
  • blood pressure tests
  • a measurement of both your weight and waist size

Your GP will also want to know about possible risk factors and will ask you:

  • whether you smoke
  • how much alcohol you drink
  • whether you have a high-fat diet
  • whether you have a first-degree relative who has a history of heart disease

Further assessment

If a diagnosis of angina is suspected, it is likely that you will be referred to a cardiology department or clinic for further assessment.

This further assessment has two main goals:

  • to confirm or disprove a suspected diagnosis of angina
  • to assess your risk of experiencing a heart attack or stroke in the future

This assessment involves a series of tests that are explained below.

Electrocardiogram (ECG)

An ECG records the rhythms and electrical activity of your heart. A number of electrodes are put on your arms, legs and chest. The electrodes are connected to a machine that records the electrical signals of each heartbeat.

An abnormal ECG reading could suggest the muscles of your heart are not receiving enough blood.

Exercise tolerance test (ETT)

An exercise tolerance test (ETT) is similar to an ECG but the test is performed when you are exercising, usually on an exercise bike or a treadmill.

An ETT can be used to measure how much exercise your heart is able to tolerate before the symptoms of angina are triggered. This information is useful for assessing the likely severity of your angina.

Myocardial perfusion scintigraphy (MPS)

A myocardial perfusion scintigraphy (MPS) is a test that can be used as an alternative to an ETT for people who are unable to exercise, or when the results of the ETT are unclear.

An MPS involves injecting a small amount of a radioactive substance into your blood. A special camera, known as a gamma camera, is then used to track the substance as it moves through your blood vessels and into your heart. This information allows healthcare professionals to determine how well blood is reaching your heart.

MPS is usually carried out both at rest and when you are exercising. If you are unable to exercise, medication can be used to replicate the effects of exercising on your heart.

Coronary angiogram

A coronary angiogram is a test used to identify whether your coronary arteries are narrowed and how severe any blockages are.

During an angiogram, a catheter (flexible tube) is passed into a vein or artery in your groin or arm, and X-rays are used to guide it into your coronary arteries. A dye is injected into the catheter to highlight the arteries supplying blood to your heart. A number of X-ray pictures are taken that will highlight any blockages.

Coronary angiograms carry a small risk of serious complications, such as a stroke or a heart attack, which is estimated to be around 1 in 1,000.

While this risk is small, healthcare professionals are unwilling to perform an angiogram unless the benefits of the procedure outweigh the potential risks. Therefore, it is likely that you will only be referred for a coronary angiogram if:

  • the diagnosis of angina remains unclear
  • your angina symptoms persist despite treatment
  • you are thought to be at significant risk of having a heart attack or stroke and surgical treatment is being considered

Unstable angina

If a diagnosis of unstable angina is suspected, you will be admitted to hospital. Depending on the severity of your symptoms, you may be placed in a general ward or in the intensive care unit (ICU).

You will be given an ECG as soon as you arrive in hospital to quickly assess whether your heart has experienced significant damage.

Blood tests will also be carried out in order to identify increased enzyme levels that are known to be released if the heart is damaged.

Due to the urgent need for treatment to prevent serious complications arising from unstable angina, treatment may be started before all of the test results are known.

Stable angina

Your treatment plan

Treatment for stable angina has three goals:

  • to provide immediate relief from the symptoms of angina
  • to prevent future episodes of angina symptoms
  • to reduce your risk of having a heart attack or stroke 

The last goal is the most important one in deciding on your recommended treatment plan.

If your risk of having a heart attack or stroke is thought to be high because your arteries are significantly narrowed - and you have other risk factors, such as high blood pressure or diabetes - a combination of surgery and medication will probably be recommended. Surgery may also be recommended if your symptoms fail to respond to treatment with medication.

If your risk of having heart attack or stroke is thought to be low to moderate, it should be possible to significantly reduce the risk by using a combination of medication and lifestyle changes. See the Prevention section above for more information.

Providing immediate relief

Glyceryl trinitrate is a medication that is widely used to provide immediate relief from the symptoms of angina. It can also be used as a preventative measure before undertaking activities that are known to trigger angina.

Glyceryl trinitrate belongs to a group of medication known as nitrates. Nitrates work by relaxing and widening the blood vessels that increase the blood supply to the heart.

Glyceryl trinitrate is available in tablet form, which you dissolve under your tongue, or as a spray. The side effects of glyceryl trinitrate include headache and dizziness.

Avoid drinking alcohol when taking glyceryl trinitrate because it can make the side effects worse. If you experience symptoms of dizziness, do not drive or operate complex or heavy machinery.

One dose of glyceryl trinitrate usually eases the pain within two to three minutes. If the first dose does not work, a second dose can be taken after five minutes, and a third dose after a further five minutes.

You should dial 999 to request an ambulance if the pain persists despite taking three doses of glyceryl trinitrate over a 15-minute period.

Your GP or cardiologist (an expert in treating heart conditions), will usually try one medication first to see whether it is effective in helping to prevent your symptoms. This is known as monotherapy.

If one medication is not effective, two medications may be recommended. This is known as combination therapy.


Beta-blockers are the preferred first-choice treatment for helping to prevent angina. They make the heart beat slower and with less force. This means that the heart needs less blood and oxygen after exercise, so angina is prevented or occurs less frequently.

Common side effects of beta-blockers include tiredness, cold hands and feet, slow heartbeat, diarrhoea and nausea.

Less common side effects of beta-blockers include sleep disturbances, nightmares and impotence.

Beta-blockers can also interact with other medicines, causing possible adverse side effects. Therefore, you should check with your GP or pharmacist before taking other medicines, including over-the-counter (OTC) medication, in combination with beta-blockers.

Beta-blockers may not be suitable for you if you have asthma, or chronic pulmonary obstruction disorder (COPD). COPD is a general term for chronic (long-term) lung diseases, such as emphysema. If this you have asthma or COPD, you may require one of the alternative medications described below.

Calcium channel blockers

Calcium channel blockers work by relaxing the muscles that make up the walls of your arteries, increasing the blood supply to the heart.

Side effects of calcium channel blockers include flushed face, headaches, swollen ankles, dizziness, tiredness, skin rashes.

However, these side effects should pass within a few days once your body gets used to the medicine. You should not drink grapefruit juice if you are taking calcium channel blockers because this can cause a drop in your blood pressure.

Long-acting nitrates

Long-acting nitrates are a similar medication to glyceryl trinitrate, except they are designed for the long-term prevention of symptoms rather than providing short-term relief.

Side effects of long-acting nitrates include headache and a flushed face. Both of these side effects should improve with time.

If you are taking long-acting nitrates, you should not take the anti-impotence medication known as sildenafil (Viagra). This is because the combination of the two medications can lead to a dangerous drop in blood pressure.

Potassium channel activators

Potassium channel activators work in a similar way to calcium channel blockers by widening the coronary arteries in order to increase blood flow to the heart.

Common side effects of potassium channel blockers include nausea, vomiting and dizziness.

If you do experience symptoms of dizziness, you should not drive or operate complex or heavy machinery.


Statins are a type of medication used to lower your blood cholesterol level. This will help prevent further damage to your coronary arteries and should reduce the risk of a heart attack or stroke occurring.

Statins work by blocking the effects of an enzyme in your liver that is used to make cholesterol.

Statins sometimes have mild side effects that can include constipation, diarrhoea, headaches and abdominal pain.


Antiplatelets are medications that are used to reduce the 'stickiness' of platelets. Platelets are tiny particles in the blood that help the blood to clot.

If a large number of platelets stick to plaque inside an artery, they can form a blood clot. If the blood clot forms inside a coronary artery, it can cause a heart attack. Taking antiplatelet medicine reduces your risk of having a heart attack.

Low-dose aspirin (usually 75mg daily) is the preferred antiplatelet medicine.

If you are allergic to aspirin or you are unable to take it due to having another health condition that may be aggravated by taking aspirin, such as stomach ulcer, alternative antiplatelet medications are available.

Angiotensin-converting enzyme (ACE) inhibitors

Angiotensin-converting enzyme (ACE) inhibitors are medicines that can be used to reduce your blood pressure.

Having high blood pressure (hypertension) also means that your heart will have to work harder than usual, which can strain the heart muscles and increase your risk of heart failure or having a heart attack.

ACE inhibitors block the activity of a hormone call angiotensin II, which narrows blood vessels. As well as stopping the heart working so hard, ACE inhibitors improve the flow of blood around the body.

ACE inhibitors have been known to reduce the supply of blood to the kidneys, which can reduce their efficiency. Therefore, blood and urine tests may be carried out before you start taking ACE inhibitors to make sure there are no pre-existing problems with your kidneys.

Annual blood and urine tests may be required if you continue to use ACE inhibitors.

Side effects of ACE inhibitors include dizziness, tiredness or weakness, headaches and a persistent, dry cough.

Most of these side effects should pass within a few days, although some people find that they continue to have a dry cough.

If they are taken with other forms of medication, including over-the-counter (OTC) medicines, ACE inhibitors can cause unpredictable side effects. Therefore, you should check with your GP or pharmacist before taking any other medication in combination with ACE inhibitors.


Surgery is usually recommended if your symptoms of angina fail to respond to medication. Surgery can also play a limited role in reducing your risk of having a heart attack or stroke, but it is not as effective as taking medication, such as statins or antiplatelets. Therefore, you will probably be required to continue to take this type of medication after your surgery.

Coronary angioplasty

Coronary angioplasty is a type of non-invasive surgery that can be used when medication has failed to help control and prevent the symptoms of angina. Non-invasive surgery is surgery that does not involve making major incisions (cuts) in your body.

During coronary angioplasty, a tiny wire with a sausage-shaped balloon at the end is put into a large artery in your groin or arm. Using X-rays to guide it, the wire is passed through your blood vessels, up to your heart, and into the narrowed section of the affected coronary artery.

The balloon is blown up inside the narrowed part of the artery in order to open it wide. A stent (short, wire mesh tube) is usually inserted into the artery to help keep it open afterwards.

Complications of a coronary angioplasty are rare, but potentially serious. They include:

  • heart attack: estimated to occur in 1 in 100 cases
  • stroke: estimated to occur in 1 in 200 cases
  • death: estimated to occur in 1 in 500 cases

Coronary artery bypass graft (CABG)

Coronary artery bypass graft (CAGB) is surgery to bypass a blockage in an artery using healthy blood vessel segments (grafts) that are taken from other parts of the body. Segments of vein from your legs or chest are used to create a new channel through which the blood can be directed past the blocked part of the artery. This allows more blood to get through into the heart muscle.

Complications of CABG are rare but potentially serious. They include:

  • heart attack: estimated to occur in 1 in 50 cases
  • stroke: estimated to occur in 1 in 50 cases

Coronary angioplasty or CABG?

While it is not always possible, you may have a choice of whether to have a coronary angioplasty or a CABG. Both types of surgery have advantages and disadvantages.

As coronary angioplasty is non-invasive, you will recover from the effects of the operation quicker than from CABG and it also has a lower rate of complications. However, research has shown that one in four people who had a coronary angioplasty required further surgery because the widened artery narrowed again, although this figure is expected to drop sharply due to improvement in stenting technology.

CABG has a longer recovery time compared with coronary angioplasty and a higher complication rate. Also, 1 in 10 people who had a CABG required further surgery. However, research published in 2009 found that CABG is usually a more effective treatment option for people who are over 65 years of age, and those with diabetes.

Discuss the benefits and risks of both types of surgery with your surgical team. 

Unstable angina

When you are first admitted to hospital, you will be given medication to prevent blood clots forming in order to reduce the risk of a heart attack or stroke.

Two widely used medications used for this purpose are heparin and fondaparinux. These medications work by interfering with the blood's ability to clot.

The results from your electrocardiogram (ECG) should indicate whether you can be treated with medication, or if you also require surgery to widen your coronary arteries. If surgery is required, a coronary angioplasty will usually be carried out because the operation can be performed more quickly than a CABG.

Once you are well enough to leave hospital, you will be given a combination of statins, antiplatelets and ACE inhibitors in order to prevent any further episodes of unstable angina occurring.


Living with a condition such as angina can cause feelings of stress and anxiety in some people, which can lead to symptoms of depression.

You may be feeling depressed if during the last month:

  • you have often felt down, depressed or hopeless
  • you have little interest or pleasure in doing things

If you think that you have depression, it is important to speak to your GP. Depression does not only affect your mental health, it can also have an adverse affect on your physical health as well.

You may also wish to contact a charity or a support group, such as CROI

(who will be able to provide you with additional support and advice. See the Useful links section for more information.

Lifestyle changes

Making lifestyle changes is the most effective way to prevent getting angina or, if you have angina, to prevent the symptoms getting worse and reduce your risk of having a heart attack or stroke.

The best way to achieve these goals is to eat a healthy, balanced diet, maintain a healthy weight, exercise regularly, drink alcohol in moderation and avoid smoking.

This will lower your blood pressure, reduce your cholesterol levels and strengthen your heart, which are three of the most effective ways of preventing angina and reducing the risk of a heart attack and stroke.


A low-fat, high-fibre diet is recommended, including plenty of fresh fruit and vegetables (at least five portions a day) and whole grains. Limit the amount of salt you eat to no more than 6g (0.2oz) a day because too much salt will increase your blood pressure. One teaspoonful of salt is equal to about 6g.

Avoid eating foods high in saturated fat because this will increase your cholesterol level. Foods high in saturated fat include:

  • meat pies
  • sausages and fatty cuts of meat
  • butter
  • ghee: a clarified butter often used in Indian cooking
  • lard
  • cream
  • hard cheese
  • cakes and biscuits
  • foods that contain coconut or palm oil

Eating some food that is high in unsaturated fat can help to decrease your cholesterol level.

Foods high in unsaturated fat include:

  • oily fish
  • avocados
  • nuts and seeds
  • sunflower
  • rapeseed
  • olive oil


Regular exercise will make your heart and blood circulatory system more efficient, it will lower your cholesterol level, and it will keep your blood pressure at a healthy level.

For people without angina, 30 minutes of moderate exercise a day, at least five times a week, is recommended.

Your GP can also give you further advice about the level of exercise suitable for you.


Drinking excessive amounts of alcohol will cause your blood pressure to rise and it will also raise the levels of cholesterol in your blood.

Therefore, sticking to the recommended limits of alcohol consumption is the best way to ensure you reduce the risk of developing high blood pressure (hypertension) and cardiovascular disease.

The recommended maximum weekly levels of alcohol consumption are 17 standard drinks of alcohol for men and 11 for women. A standard drink of alcohol is equal to about half a pint of beer, a small glass of wine or a single pub measure of spirits.


Smoking can cause your arteries to narrow, which can lead to a rise in your blood pressure. Smoking is also a major risk factor for developing cancer

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Your GP or pharmacist will also be able to provide you with help and advice on giving up smoking.

Content provided by NHS Choices and adapted for Ireland by the Health A-Z.

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