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Coronary artery spasm is a temporary, sudden narrowing of one or more of the coronary arteries.

The spasm slows or stops blood flowing through the artery and so reduces the blood supply to the heart muscle. Coronary artery spasm is sometimes called variant angina or Prinzmetal's angina.

About 1 person in every 50 with angina has coronary artery spasm. Coronary artery spasm is most common in people aged between 40 and 70 years.

Coronary artery spasm is much more common in people who smoke or have high blood pressure or a high blood cholesterol level. However, coronary artery spasm may occur without any risk factors for heart disease. Risk factors for heart disease include smoking, diabetes, high blood pressure and high cholesterol.

Coronary artery spasm often occurs in coronary arteries that have not already become blocked with fatty patches or plaques (atheroma). However, coronary artery spasm can also occur in coronary arteries that are already partially blocked with atheroma.

Coronary artery spasm may occur without any obvious cause. At other times the spasm may be triggered by various factors such as:

  • Emotional stress.
  • Alcohol.
  • Exposure to cold.
  • Stimulant drugs (such as amfetamines and cocaine).
  • A tendency that runs through families (genetic)

Coronary artery spasm may occur without any symptoms. The most common symptom is heart chest pain (angina). If the coronary artery spasm is severe and lasts long enough then it may cause a heart attack (myocardial infarction).

With angina, the pain is usually severe and felt under the breast bone (sternum) or on the left side of the chest. The pain is often described as crushing, pressure, squeezing or tightness. The pain may spread to the neck, jaw, shoulder or arm. Angina can also be caused by cardiac syndrome X (CSX). 

The chest pain caused by coronary artery spasm often occurs at rest and commonly doesn't occur during exercise. This is very different from angina due to fatty patches or plaques (atheroma), when the pain is usually triggered by exercise and goes away when you rest. The chest pain may occur at the same time each day and most often occurs during the night and early morning. The pain can be very variable but usually lasts between 5 and 30 minutes. It can occasionally spread to the back. The pain does not improve with change of position, unlike pericarditis, when it is sometimes made better by leaning forward.

Coronary artery spasm may also cause shortness of breath. A severe episode of coronary artery spasm may cause a loss of consciousness.

Coronary artery spasm is sometimes mistaken for other heart-related (cardiac) causes of chest pain such as pericarditis, a heart attack and cardiomyopathy. Non-cardiac causes of chest or upper tummy pain may need to be ruled out such as gallbladder disease and stomach ulcers.

If you are thought to have heart chest pain (angina), you will usually be referred to see a specialist for investigations. The initial investigations will include blood tests, a 'heart tracing' (electrocardiogram, or ECG), an ultrasound heart scan (echocardiogram, or 'echo') and coronary angiography. Other investigations may also be used, including a myocardial perfusion scan, a radionuclide (isotope) scan or a magnetic resonance imaging (MRI) scan.

The coronary angiogram may be normal if there is no blockage of the coronary arteries caused by fatty patches or plaques (atheroma). However, coronary artery spasm can be triggered by injecting a chemical into one of your veins. The chemical is otherwise safe and the coronary angiogram may then show temporary narrowing of the coronary arteries in people with coronary artery spasm. This is called a provocation test.

The aim of treatment is to control chest pain and to prevent a heart attack (myocardial infarction). The most important aspects of treatment are to avoid any known triggers for coronary artery spasm and to reduce the risk of heart disease. Reducing the risk of heart disease includes:

See the separate leaflet called Cardiovascular Disease (Atheroma).

Glyceryl trinitrate (GTN) can be used to relieve an episode of chest pain. Your healthcare provider may prescribe other medicines to prevent chest pain. You may also need a type of medicine called a calcium-channel blocker or a long-acting nitrate. Beta-blockers should be avoided because they may make this condition worse.

You will need to be referred to a heart specialist for further investigations and treatment. Further treatments may include coronary angioplasty if you also have coronary artery blockage caused by fatty patches or plaques (atheroma).

An implantable cardioverter defibrillator may be needed if you are at risk of life-threatening abnormal heart rhythms caused by coronary artery spasm. See the separate leaflet called Abnormal Heart Rhythms (Arrhythmias) for more details.

Coronary artery spasm may cause an abnormal heart rhythm (arrhythmia), which may be life-threatening. Severe and prolonged coronary artery spasm may cause a heart attack (myocardial infarction).

Coronary artery spasm is a long-term condition. However, treatment most often helps to control symptoms. The outcome (prognosis) for people with coronary artery spasm is generally good if they follow treatment recommendations and avoid certain triggers.

The outcome is not as good in people who also have blockage of the coronary arteries caused by fatty patches or plaques (atheroma).

Coronary artery spasm may be a sign that you have a high risk for heart attack (myocardial infarction) or potentially life-threatening irregular heart rhythms (arrhythmias).

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Further reading and references

  • Stable angina: management; NICE Clinical Guideline (August 2016)

  • Wee Y, Burns K, Bett N; Medical management of chronic stable angina. Aust Prescr. 2015 Aug38(4):131-6. Epub 2015 Aug 3.

  • 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 May7(5):453-63. doi: 10.1016/j.jcin.2014.01.157. Epub 2014 Apr 16.

  • Hung MJ, Hu P, Hung MY; Coronary artery spasm: review and update. Int J Med Sci. 2014 Aug 2811(11):1161-71. doi: 10.7150/ijms.9623. eCollection 2014.

  • Agrawal S, Mehta PK, Bairey Merz CN; Cardiac Syndrome X: Update. Heart Fail Clin. 2016 Jan12(1):141-56. doi: 10.1016/j.hfc.2015.08.012.

  • Assessing fitness to drive: guide for medical professionals; Driver and Vehicle Licensing Agency

  • Saraste A, Knuuti J; ESC 2019 guidelines for the diagnosis and management of chronic coronary syndromes : Recommendations for cardiovascular imaging. Herz. 2020 Aug45(5):409-420. doi: 10.1007/s00059-020-04935-x.

  • Ford TJ, Berry C; Angina: contemporary diagnosis and management. Heart. 2020 Mar106(5):387-398. doi: 10.1136/heartjnl-2018-314661. Epub 2020 Feb 12.

  • Teragawa H, Oshita C, Ueda T; Coronary spasm: It's common, but it's still unsolved. World J Cardiol. 2018 Nov 2610(11):201-209. doi: 10.4330/wjc.v10.i11.201.