What is angina?
Angina is a heart condition that causes temporary pain or an uncomfortable feeling in the chest. It often occurs during exercise but can also be triggered by anxiety, stress, eating a large meal, or by cold or windy weather. An angina attack usually lasts from one to 10 minutes and may be relieved by resting.
Angina is more common in men than in women and incidence increases with age. Angina is the most common form of coronary heart disease and is thought to affect around 1.3 million people in the UK overall. Angina is more common in people from the Indian subcontinent and in people with diabetes.
What causes angina?
Angina is caused by an imbalance between the amount of oxygen supplied to the heart and the amount needed. There are four types of angina: stable angina, unstable angina, variant (Prinzmetal's) angina and microvascular angina (also known as cardiac syndrom X). In all types of angina the pain is caused by the heart muscle becoming short of oxygen. This may be the result of narrowed arteries (as in stable angina), or as a result of a coronary artery spasm (as may occur in unstable angina or variant angina). Narrowing of the arteries also occurs in unstable angina and often in variant angina. Microvascular angina is caused by spasms within the walls of small arterial blood vessels causing reduced blood flow to the heart muscle.
Narrowing of the arteries is caused by atherosclerosis, which is the gradual build-up of fatty deposits within the arteries. This build-up tends to happen with age and there are many risk factors that can increase the likelihood of it occurring, including smoking, raised cholesterol, high blood pressure, diabetes and being overweight. Some people develop angina without having any of these risk factors. If you have a close family member who has had angina or a heart attack at an early age you may also be at increased risk.
What are the symptoms of angina?
As mentioned above, angina causes temporary pain or an uncomfortable feeling in the chest. In stable angina, the pain is predictable and usually occurs at the same level of exercise or activity each time. Angina is described as unstable when it occurs with increasing frequency and severity. Unstable angina can occur at any time, often during exercise but also at rest. The pain caused by unstable angina is more prolonged than in stable angina and is not quickly relieved by nitrates (see 'What treatment is available?'). This condition can deteriorate rapidly.
Variant angina is a rare form of angina caused by coronary artery spasm. It is unpredictable and can occur at rest. Microvascular angina may be a a symptom of coronary microvascular disease (MVD). Chest pain can last for longer than 30 minutes and may be more severe than other types of angina pain.
Chest pain can also be caused by anxiety and tension but is a different kind of pain to that experienced in angina - your doctor will be able to determine what is causing your chest pain.
Usually, angina subsides with rest but you may be prescribed a spray or tablet containing glyceryl trinitrate to ease the pain. If the pain does not settle within five minutes, you should take another tablet or more spray. If the pain still does not settle then you should seek medical attention urgently. The symptoms of a heart attack are usually stronger than those of angina. The pain is more severe and does not go away, and may be accompanied by sweating, nausea, shortness of breath, fatigue and severe anxiety. Do not hesitate to seek help straight away if you think you may be having a heart attack.
Are there any tests needed?
Your doctor may order tests to see if you have any other heart problems and to determine the cause of the angina. You may have an electrocardiogram (ECG) in which two or more electrodes will be placed on your skin (one on your chest) - the electrodes will then be connected to a machine (an electrocardiograph) which will produce a tracing of the electrical activity of your heart. This will help the doctors to identify the problem. As angina is often triggered by exercise an ECG may be carried out while you are exercising.
High cholesterol is a risk factor for angina and can increase atherosclerosis - a blood test will show if your cholesterol levels are high.
A procedure called coronary angiography may be carried out if other procedures such as angioplasty or coronary artery surgery are being considered. Your doctor will explain these procedures to you if necessary.
What treatment is available?
There are several different drugs available to treat angina. These drugs cannot cure angina but can relieve the discomfort of an attack or help to prevent an attack. There are two main types - those which increase the blood supply to the heart and those which reduce the workload of the heart.
Tablets that dissolve under the tongue (sublingual tablets) or sublingual sprays can be used to treat angina attacks. Drugs used to prevent attacks may be given as tablets or as patches or ointment applied to the skin.
Nitrates relieve both stable and unstable angina by dilating the blood vessels. This dilation eases the workload of the heart and also widens the coronary arteries. Nitrates can be given to prevent an attack at night or prior to exercise.
Glyceryl trinitrate (GTN) is a short-acting nitrate that is often used when an attack occurs. It is available as sublingual tablets, which are dissolved under the tongue, or as a sublingual spray (eg, Coro-Nitro®, Glytrin®, Nitrolingual, Nitromin®). Slow-release forms of glyceryl trinitrate are also available and can be used to treat and prevent attacks. Glyceryl trinitrate is also available in patches (eg, Deponit®, Minitran®, Nitro-Dur®, Transiderm-Nitro®) that are applied directly to the skin to prevent an attack and as an ointment (Percutol®).
Isosorbide dinitrate and isosorbide mononitrate are longer-acting nitrates that are used mainly to prevent attacks. Isosorbide dinitrate is available as slow-release tablets that can be used to prevent angina attacks. It is also available as immediate-release tablets, which can be used for treatment and prevention of angina attacks. Isosorbide mononitrate is used to prevent an attack and is available as slow-release tablets or immediate-release tablets.
For stable angina, commonly brought on by exercise, beta-blockers may be given. These work by slowing down the heart rate, which in turn reduces the workload of the heart. When taken regularly they can reduce the frequency of angina attacks. Beta-blockers include acebutolol, atenolol, bisoprolol, carvedilol, labetalol, metoprolol, nadolol, oxprenolol, pindolol, propranolol and timolol. Capsules containing the beta-blocker bisoprolol in combination with aspirin are also available.
Ivabradine (Procoralan®) is a drug that may be prescribed for patients with stable angina for whom beta-blockers are not suitable. This drug acts on the heart's pacemaker to lower the heart rate, thereby reducing the workload of the heart.
Calcium-channel blockers can also reduce the frequency of angina attacks. These drugs act by causing relaxation of the coronary arteries and also the heart muscle, thereby lowering blood pressure and reducing workload of the heart. Calcium channel blockers include amlodipine, diltiazem, felodipine, nicardipine, nifedipine and verapamil.
Nicorandil (eg, Ikorel) is a type of drug known as a potassium channel activator and acts by dilating the arteries. It can be used for both prevention and treatment of angina.
Ranolazine (Ranexa®) is a drug that may be added to treatment for stable angina if other anti-anginal drugs are not working well enough or if you are intolerant of other drugs. The exact way in which this drug works is not known but it is thought to improve relaxation of the heart muscle.
You may be given a combination of drugs depending on the cause of your angina and whether you have additional medical problems.
For very severe angina surgery or angioplasty may be recommended.
Angioplasty is a procedure used to widen arteries that have become narrowed by atherosclerosis. A "balloon catheter" is inserted through the skin into the affected blood vessel; the balloon is then inflated, flattening the fatty deposit that is narrowing the artery against the artery wall. This procedure is used in people who have short lengths of narrowed arteries.
If angina cannot be relieved by medicines or angioplasty or if the arteries are severely narrowed then a coronary artery bypass graft (CABG) may be necessary. In this procedure a vein from elsewhere in the body, usually from one of your legs, is grafted into the heart to bypass the blocked or narrowed arteries.
- If you smoke, try to stop - this is very important because smoking is a major cause of coronary artery narrowing and the most important risk factor for angina.
- Reduce your fat intake to reduce cholesterol levels. Changes in your diet can also lessen the risk of your arteries becoming narrowed by the build-up of fatty deposits.
- Reduce the amount of salt in your diet to help to lower your blood pressure, which in turn reduces the workload of the heart.
- Begin an exercise programme to strengthen your heart and enable it to deal with oxygen more efficiently. Check with your doctor before starting any exercise regimen.
- Keep your weight at a healthy level - if you are overweight your heart has to work harder to pump blood around your body.
Further information available from:
British Heart Foundation
Greater London House
180 Hampstead Road
London NW1 7AW
Tel: 020 7554 0000
Heart Help Line: 0300 330 3311 (Monday to Friday, 9am-5pm)
Fact sheet provided by MIMS
Date last reviewed: May 2014