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Microvascular Angina (Cardiac Syndrome X)

Microvascular Angina (Cardiac Syndrome X)

Microvascular angina (previously known as cardiac syndrome X (CSX)) is a type of angina. People with CSX have chest pain and there may be changes on the 'heart tracing' (electrocardiograph, or ECG) during a stress test. Typically, the common type of angina can be confirmed by an angiogram. However, in CSX the angiogram is usually normal.

There is no agreed definition for CSX. The cause of CSX and the treatment required can be very variable for people with CSX. The underlying cause may be sudden narrowing (spasm) of normal coronary arteries. However, the term CSX is often used to describe a condition of narrowing of the much smaller blood vessels which supply blood to the heart muscle (microvascular angina). Therefore, a better name for CSX would perhaps be 'microvascular angina'.

There are medicines that may help manage the pain, although they do not always work. Altering your lifestyle (diet, exercise and weight) is thought to help prevent CSX developing. The symptoms of CSX may improve over time.

CSX is thought to be a type of angina. Angina is a pain that comes from the heart. The common type of angina is usually caused by narrowing of the heart (coronary) arteries. This causes a reduced blood supply to a part, or parts, of your heart muscle. The blood supply may be good enough when you are resting. When your heart works harder (when you walk fast or climb stairs and your heart rate increases) your heart muscle needs more blood and oxygen. If the extra blood that your heart needs cannot get past the narrowed coronary arteries, the heart responds with pain.

The narrowing of the arteries is caused by atheroma. Atheroma is like fatty patches or plaques that develop within the inside lining of arteries. (This is similar to water pipes that get furred up with limescale.) Plaques of atheroma may gradually form over a number of years. They may be in one or more places in the coronary arteries.

In CSX you feel chest pain when your heart works harder but the heart arteries appear to be normal on coronary angiography.

There is no agreed definition for CSX. The underlying cause may be sudden narrowing (spasm) of normal coronary arteries without any atheroma. However, the term CSX is often used to describe microvascular angina. The larger blood vessels in the heart (that show up in investigations) are normal. However, much smaller vessels (the microvasculature) are thought to be where there is narrowing. Therefore, a better name for CSX would perhaps be 'microvascular angina'.

Because doctors have not been able to decide exactly what CSX is, there are no precise numbers of how many people have the condition. Each year about 20,000 people in the UK develop angina for the first time. Of these people, about 1 woman in 5 and 1 man in 10 will have CSX. Unlike the more common type of angina, CSX is more common in women than in men. Certain factors make CSX more likely to develop - for example:

  • Having a high cholesterol level.
  • Smoking.
  • Being overweight and unfit.
  • Having high blood pressure.
  • Women during or after the menopause.
  • Having mild arthritis.

The common symptom is a pain, ache, discomfort or tightness that you feel across the front of the chest when you exert yourself - for example, when you walk up a hill or against a strong, cold wind. You may also, or just, feel the pain in your arms, jaw, neck or stomach.

An angina pain does not usually last long. It will usually ease within 10 minutes when you rest. Angina pain may also be triggered by other causes of a faster heart rate. For example, when you have a vivid dream or an argument. The pains also tend to develop more easily after meals.

CSX pain can be quite severe and disabling.

When you see your doctor, they will want to know all about the pain and when it happens. Angina-type pains have a pattern. They will also use this information to rule out other causes of pain, such as pain from the oesophagus (gullet) or from your muscles and joints. They will usually also ask you about your lifestyle (whether you smoke and drink), your diet and whether you exercise. They may also take a blood pressure reading. They may ask you to have a blood test to check your cholesterol level.

If they think angina is likely, they may prescribe you a glyceryl trinitrate (GTN) spray or tablets. You take a dose under your tongue when your angina pain develops. GTN is absorbed quickly into the bloodstream, from under the tongue, and should ease the pain within a few minutes. It works by relaxing the blood vessels. This reduces the workload on the heart. It also helps to widen the coronary arteries and increase the flow of blood to the heart muscle. A dose of GTN may cause a headache and/or flushing for a short while. If this medicine does not relieve the pain quickly, tell your doctor. Further tests may be needed.

A 'heart tracing' (electrocardiograph, or ECG) is often done. However, this is usually normal when you are not exerting yourself. When you have an ECG whilst exercising (sometimes called a stress test) the doctor may be able to see a typical pattern (a downward-sloping ST segment). This helps to make the diagnosis.

Typical angina can be confirmed by an angiogram test. A special dye is injected into the arteries or the heart (coronary arteries). X-ray equipment shows up the structure of the arteries and can also show the location and severity of any narrowing. The angiogram is usually normal in people with CSX. However, the angiogram may show narrowing when certain chemicals (eg, acetylcholine) are injected. The injection of these chemicals causing abnormalities in the angiogram helps to diagnose CSX.

Cardiac syndrome X (CSX) can be difficult to treat but a range of different treatments can help. The treatments include reducing risk factors (especially regular exercise).

Several different medicines may also be helpful, including calcium-channel blockers, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, ranolazine and statins. Oestrogen replacement therapy may also have a role for women who are affected after the menopause. Nitrates such as GTN may be effective for symptom relief.

Other treatments include a a piece of equipment called a transcutaneous electrical nerve stimulation (TENS) machine or a spinal cord stimulator to reduce pain. Relaxation exercises, hypnotherapy and cognitive behavioural therapy can also be helpful.

Sometimes other medicines may also be advised, if you have high blood pressure or a high cholesterol level.

Certain factors increase the risk of more fatty patches or plaques (atheroma) forming, which can make any type of angina worse. These are discussed in more detail in a separate leaflet called Preventing Cardiovascular Diseases. Briefly, risk factors that can be modified and may help to prevent angina from becoming worse include:

  • If you smoke, you should make every effort to stop.
  • Your blood pressure should be checked regularly, at least once a year, if you have angina. If you have high blood pressure it can be treated.
  • If you are overweight, losing some weight is advised. Losing weight will reduce the amount of workload on your heart and also help to lower your blood pressure.
  • High cholesterol should be treated with a medicine (statin) to reduce the cholesterol level.
  • If possible, you should aim to do some moderate physical activity on most days of the week for at least 30 minutes. For example, brisk walking, swimming, cycling, dancing, gardening, etc. (Occasionally, angina is due to a heart valve problem where physical activity may not be so good. Ask your doctor to confirm that you can undertake regular physical activity.)
  • You should aim to eat a healthy diet. A healthy diet means:
    • At least five portions (and ideally 7-9 portions) of a variety of fruit and vegetables per day.
    • You should not eat much fatty food such as fatty meats, cheeses, full-cream milk, fried food, butter, etc. Ideally, you should use low-fat, mono-unsaturated or polyunsaturated spreads.
    • Try to include 2-3 portions of fish per week, at least one of which should be oily (such as herring, mackerel, sardines, kippers, salmon, or fresh tuna).
    • If you eat red meat, it is best to eat lean red meat, or eat poultry such as chicken.
    • If you do fry, choose a vegetable oil such as sunflower, rapeseed or olive.
    • Try not to add salt to food, and limit foods which are salty.
  • Drinking a small or moderate amount of alcohol is probably beneficial to the heart. That is, 1-2 units per day - which is up to 14 units per week.

Cardiac syndrome X (CSX) symptoms may improve over time. Unfortunately, in about 1 out of 5 people, their symptoms become worse. The pain can become difficult to relieve and this affects the quality of life for people with CSX.

Further help & information

British Heart Foundation

Greater London House, 180 Hampstead Road, London, NW1 7AW

Tel: (Heart Helpline) 0300 330 3311, (Admin) 020 7554 0000

Further reading & references

  • Radico F, Cicchitti V, Zimarino M, et al; Angina pectoris and myocardial ischemia in the absence of obstructive coronary artery disease: practical considerations for diagnostic tests. JACC Cardiovasc Interv. 2014 May;7(5):453-63. doi: 10.1016/j.jcin.2014.01.157. Epub 2014 Apr 16.
  • Jones E, Eteiba W, Merz NB; Cardiac syndrome X and microvascular coronary dysfunction. Trends Cardiovasc Med. 2012 Aug;22(6):161-8. doi: 10.1016/j.tcm.2012.07.014. Epub 2012 Sep 29.
  • Herrmann J, Kaski JC, Lerman A; coronary microvascular dysfunction in the clinical setting: from mystery to reality. Eur Heart J. 2012 Nov;33(22):2771-2782b. doi: 10.1093/eurheartj/ehs246. Epub 2012 Aug 22.
  • Sedlak T, Izadnegahdar M, Humphries KH, et al; Sex-specific factors in microvascular angina. Can J Cardiol. 2014 Jul;30(7):747-55. doi: 10.1016/j.cjca.2013.08.013. Epub 2014 Feb 27.
  • Park JJ, Park SJ, Choi DJ; Microvascular angina: angina that predominantly affects women. Korean J Intern Med. 2015 Mar;30(2):140-7. doi: 10.3904/kjim.2015.30.2.140. Epub 2015 Feb 27.
  • Marinescu MA, Loffler AI, Ouellette M, et al; Coronary microvascular dysfunction, microvascular angina, and treatment strategies. JACC Cardiovasc Imaging. 2015 Feb;8(2):210-20. doi: 10.1016/j.jcmg.2014.12.008.
  • Agrawal S, Mehta PK, Bairey Merz CN; Cardiac Syndrome X: update 2014. Cardiol Clin. 2014 Aug;32(3):463-78. doi: 10.1016/j.ccl.2014.04.006. Epub 2014 Jun 2.
  • Petersen JW, Pepine CJ; Microvascular coronary dysfunction and ischemic heart disease: where are we in 2014? Trends Cardiovasc Med. 2015 Feb;25(2):98-103. doi: 10.1016/j.tcm.2014.09.013. Epub 2014 Nov 7.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Hayley Willacy
Current Version:
Dr Colin Tidy
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
13840 (v3)
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