Angina is chest pain or discomfort caused by a lack of oxygen reaching the heart muscle, usually caused by narrowed or blocked coronary arteries.
Angina can affect people in different ways and the symptoms may vary at different times. It usually lasts only a few minutes and can be relieved by rest and/or medicines.
The typical symptom is chest pain that is typically described as:
- pain or tightness that is usually felt across the centre of the chest; or
- an unpleasant feeling or discomfort, like a tightness or weight on the chest.
Angina pain may also be felt in:
- either or both shoulders;
- the neck or jaw;
- down one or both arms (usually the left arm); and
- in the hands.
Some people experience angina pain in only one of these areas and not in the chest at all.
Other angina symptoms that may accompany chest pain or discomfort include:
- nausea (feeling sick);
- light-headedness; and
Women often report these symptoms, with or without the typical angina chest pain.
Others, in particular older people and people with diabetes, may experience very little or no pain or other symptoms.
Angina is usually brought on by:
- after a heavy meal; or
- in cold weather.
Stable versus unstable angina
Stable angina is angina that:
- lasts a short time (less than 10 minutes);
- feels similar each time;
- occurs in predictable circumstances, such as with exertion or emotional stress; and
- is relieved with rest or medicines.
Angina can be classified as stable if its pattern has remained unchanged over the past month.
Unstable angina is angina that:
- occurs in circumstances that are not typical, such as at rest or during the night;
- has symptoms that are more severe, last longer or are unusual for you; or
- is not relieved with rest or medicines.
You should see a doctor if you experience chest discomfort or other symptoms associated with angina for the first time, or if you have known angina and your symptoms change.
Angina occurs when the oxygen demand of your heart muscle exceeds that which is supplied by the coronary arteries (the blood vessels that supply your heart with oxygen).
Oxygen demand is usually increased by exercise or emotion.
Oxygen supply is reduced, in most cases, by coronary artery disease. This occurs when fatty deposits build up in the coronary arteries resulting in narrowing of the arteries and reduced blood flow.
Oxygen supply is also reduced in people with anaemia (reduced haemoglobin – the oxygen-carrying protein found in blood).
Angina is very occasionally caused by spasms of coronary arteries alone, without blockage.
There is usually no permanent damage to the heart muscle from an episode of angina.
Tests and diagnosis
Your doctor will ask about your symptoms and your past medical history, and perform a physical examination.
Tests that can help confirm a diagnosis of coronary artery disease include the following.
- Exercise stress electrocardiogram (ECG), or stress test. An ECG records the electrical activity in the heart. An ECG that is performed while you exercise can detect changes that can indicate reduced blood flow to the heart muscle – a sign of coronary heart disease.
- Stress echocardiogram is an imaging test that can show how the heart is pumping and working at rest compared with when it is under stress.
- Coronary angiogram is a test where a catheter (a long, thin, flexible tube) is inserted into a blood vessel in your groin and then threaded to the coronary arteries. Special dye is injected into the coronary arteries via the catheter and X-rays are taken, which can show blockages in the coronary arteries.
Aims of treatment
Treatment for angina aims to:
- provide relief from symptoms such as chest pain;
- prevent further attacks of angina; and
- reduce your risk of having a heart attack.
The type of angina you have (stable or unstable) and the severity of it will guide your doctor or specialist in managing your condition. Treatments include:
- angioplasty and stenting;
- coronary artery bypass surgery; and
- lifestyle modification (e.g. stopping smoking, eating healthily, losing weight if necessary).
A combination of treatments is often needed.
Most of the medicines prescribed by your doctor for your angina are aimed at:
- improving blood flow to the heart muscle so that it gets more oxygen;
- preventing further narrowing and the formation of blood clots in the coronary arteries; and
- making the heart pump more slowly so it doesn't need as much oxygen.
Aspirin and other medicines to prevent blood clots
Taking aspirin has been shown to reduce the risk of heart attack and death in people with angina when taken correctly. This is because it can prevent blood clots from forming, which may block the coronary arteries, causing a heart attack. However, aspirin can cause stomach upset and gut disorders so ask your doctor whether aspirin is suitable for you.
Other medicines that help prevent blood clots, including clopidogrel (brand names Iscover, Piax and Plavix), prasugrel (Effient), and ticagrelor (Brilinta), may also be used in certain circumstances.
(Note: These clot-preventing medicines can make you more likely to bleed during surgery, including dental surgery. If you need to have an operation, check with your doctor whether and when these medicines should be stopped beforehand.)
Nitrates have been used to treat angina for more than 100 years and are available as patches, spray and tablets.
Nitrates can relieve angina by opening up the coronary arteries and so increasing blood flow to the heart muscle. They work very quickly to make it easier for the heart to pump.
Nitrates are used in 2 ways:
- to relieve angina pain when it comes on; and
- as maintenance medication to stop episodes of angina from happening in the first place.
Short-acting nitrates are used to stop an episode of angina once it starts. Sometimes short-acting nitrates are also taken as a precaution before doing any activity that is likely to bring on angina. These nitrates come in the form of tablets that you put under your tongue or in your cheek, or a spray which you spray under the tongue.
Sometimes you may feel dizzy or have a headache after using nitrates to stop angina. This is because the blood vessels to the brain are also opening up. You may need to sit or lie down for a few minutes.
Longer acting nitrates are used as ongoing maintenance medication to prevent angina from happening. These may take the form of skin patches or tablets.
As your body can get used to the effects of nitrates and stop responding to them, your doctor may advise you on specific times of day you should take them so that there is a gap when you are nitrate-free to stop the body becoming accustomed to the nitrates and developing tolerance to them.
Nitrates may be prescribed by your doctor on their own or to be taken with other medicines for your angina.
Nitrate tablets have a limited shelf life and your doctor or pharmacist may give you instructions on how to keep them. Follow these instructions carefully.
Nitrates available include:
- glyceryl trinitrate (short-acting brands include Anginine and Nitrolingual Pumpspray; long acting brands include Transiderm-Nitro and Nitro-Dur);
- isosorbide mononitrate (long acting – brands include Duride, Imdur Durules and Monodur Durules); and
- isosorbide dinitrate (brands include Sorbidin and Isordil).
Nitrates and Viagra, Cialis or Levitra
People taking nitrates should not take some medicines used to treat erectile dysfunction, such as sildenafil (brand names Viagra, Vedafil), tadalafil (brand name Cialis) or vardenafil (brand name Levitra) because this could lead to a large, sudden and potentially fatal drop in blood pressure or cardiac arrest.
Beta-blockers slow the heart rate and lower the pressure in the arteries so the heart does not need as much oxygen as normal to pump. This makes it less likely that angina will occur, as the heart muscle should have enough oxygen to work effectively. Beta-blockers have also been shown to reduce the risk of death and heart attack in people who have had a previous heart attack.
Some beta-blockers appear to be more effective in angina than others.
Beta-blockers which are used for angina include:
- atenolol (brand names include Noten, Tenormin and Tensig); and
- metoprolol (brand names include Betaloc, Lopresor, Metrol and Minax).
Like many medicines, beta-blockers can have side effects. These may include: bad dreams, fatigue, dizziness, upset stomach and depression. Some beta-blockers may not be suitable for people with asthma or diabetes.
Calcium channel blockers or calcium antagonists
These medicines reduce the heart rate and slightly enlarge the coronary blood vessels by slowing down the rate at which calcium enters the heart muscle and blood vessel walls. This has the end result of improving the blood flow to the heart muscle and reducing the workload on the heart.
Your doctor may prescribe certain classes of calcium channel blockers in conjunction with a beta-blocker, or may prescribe a calcium channel blocker alone if you are unable to take a beta-blocker. Among the most common side effects of the calcium channel blockers are headaches and dizziness.
Some of the calcium channel blockers available are:
- diltiazem (brand names include Cardizem CD and Vasocardol CD);
- verapamil (brand names include Anpec, Cordilox, Isoptin and Veracaps SR);
- amlodipine (brand names include Nordip, Norvasc and Perivasc); and
- nifedipine (brand names include Adalat Oros, Addos XR and Adefin XL).
Ivabradine (brand name Coralan) may be used to treat certain people with uncontrolled symptoms who are not able to take other medicines.
Nicorandil (brand name Ikorel) is a medicine that may be used for the treatment of stable angina when there are ongoing symptoms despite maximal medical treatment and in situations where surgery is not appropriate.
It works by opening the coronary arteries and relaxing smooth muscles in the blood vessels and so reduces angina. The most common side effects of nicorandil are headache and abdominal pain.
Perhexiline maleate (brand name Pexsig) is used to treat moderate to severe angina which doesn't respond to treatment with other angina medications or where other treatments aren't suitable. People who take perhexiline must have regular blood tests to monitor the level of drug in their body to make sure that it stays within acceptable levels.
Your doctor may prescribe perhexiline tablets in conjunction with other medicines for angina. The most common side effects when starting perhexiline are nausea and dizziness.
While cholesterol-lowering medicines, such as statins, do not have a direct effect on the symptoms of angina, by reducing cholesterol build-up in the coronary arteries, they can reduce the risk of having a heart attack or stroke.
Angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs)
ACE inhibitors and ARBs help relax blood vessels and lower blood pressure, and have been shown to reduce the likelihood of heart attack and stroke in people at risk.
Other angina treatments
Serious angina that does not respond to medical therapy may be treated by physically re-opening the coronary arteries.
- Coronary angioplasty (also called percutaneous coronary intervention) is a procedure that can be performed to unblock the coronary arteries. It involves the insertion of a long, thin, flexible tube called a catheter into a blood vessel, usually in the groin, which is then threaded through to the coronary arteries. Once the blockage in the coronary artery is found, a balloon on the end of the catheter can be inflated to open up the blood vessel. Sometimes a stent (a thin tube) is placed in the coronary artery to keep it open.
- Coronary artery bypass surgery is open heart surgery that involves using a vein or artery graft to bypass the blocked coronary artery and provide a new channel through which blood can flow.
Cardiac rehabilitation, an exercise-based programme is designed to improve cardiac blood flow, and may reduce angina.
Lifestyle changes that could improve your heart health include:
- Eating a wide variety of nutritious foods every day from these 5 food groups: vegetables; fruit; grain foods (mostly wholegrain); lean meats, poultry, fish eggs, tofu, nuts and seeds and legumes/beans; and dairy foods (mostly reduced fat).
- Limiting foods containing saturated fat, added salt, added sugars and alcohol.
- Not smoking.
- Having your blood pressure checked regularly.
- Having your cholesterol tested regularly.
- Enjoying regular physical activity, however, if you already have angina, consult your doctor before beginning any exercise programme.
- Maintaining a healthy body weight.
- Developing ways to cope with stress.
Angina vs heart attack
Angina symptoms are associated with a temporary reduction in blood flow to part of the heart muscle leaving no damage to the muscle itself. Rest and medicines, including nitrate tablets or spray, can help relieve angina pain.
A heart attack results from a blockage in a coronary artery which causes permanent damage to the heart muscle. The pain associated with a heart attack usually lasts longer than 10 minutes and is sometimes not relieved by nitrate tablets or spray. However, some heart attacks, particularly in people with diabetes, may be painless. If you have significant risk factors for coronary artery disease it is a good idea to have regular tests to detect these silent episodes.
If your pattern of angina alters or worsens, discuss it with your doctor immediately.