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Cardiac Syndrome X
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Cardiac Syndrome X
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Related terms: angina, microvascular angina

Cardiac syndrome X patients have the pain of angina, but they do not have coronary artery disease (CAD). So even though patients with cardiac syndrome X have symptoms of CAD, the coronary arteries are clear of blockages.

Cardiac syndrome X is more common in women, especially women who have gone through menopause. It is not life threatening and does not increase your risk of heart attack or CAD.

What are the symptoms?

The pain of angina starts in the center of the chest, but the pain may spread to your left arm or your neck, back, throat, or jaw. You may have numbness or a loss of feeling in your arms, shoulders, or wrists. Patients with cardiac syndrome X often have chest pain after they exercise.

When patients with cardiac syndrome X have an exercise stress test, the results may look as though they have CAD. But when doctors use a test called coronary angiography to look for blockages in the coronary arteries, the arteries look clear and normal.

What causes cardiac syndrome X?

There are many theories about what causes cardiac syndrome X. Some doctors think it has to do with how patients feel pain, while others think it may be linked to low levels of the female hormone estrogen.

New research has shown that cardiac syndrome X is most likely caused by a form of angina called microvascular angina. In microvascular angina, the small blood vessels in the heart (called capillaries) tighten or constrict. This tightening reduces the blood flow in the heart and causes the pain of angina. But because these capillaries are so tiny, they do not increase the risk of heart attack. They are also too small to detect with the standard tests that doctors would normally use to see larger vessels.

How is cardiac syndrome X diagnosed?

Cardiac syndrome X is usually diagnosed by using many of the same tests used to diagnose CAD. These tests will help your doctor determine if you have cardiac syndrome X and not CAD.

  • A baseline electrocardiogram (ECG or EKG), which records your heart's electrical activity while you sit quietly. An exercise ECG, also known as a stress test, will show how your heart responds to increasing exercise. 
  • An exercise radioisotopic test, also called a nuclear stress test, to show how blood flows through your arteries.
  • Echocardiography, which uses sound waves to produce an image of the heart to see how it is working.

In patients with CAD, coronary angiography usually shows a blocked artery that slows blood flow to the heart. But in patients with cardiac syndrome X, the test results are completely normal. If you have an abnormal exercise stress test and a normal coronary angiogram, your doctor may suspect that you have cardiac syndrome X.

Before making a firm diagnosis, your doctor may check for other conditions that could be causing your symptoms, including high blood pressure or heart valve disease.

How is cardiac syndrome X treated?

A number of medicines can help relieve the angina pain that comes with cardiac syndrome X.

  • A medicine called nitroglycerin (nitro) can widen or dilate the arteries and improve blood flow to your heart. Nitro can be given through a skin patch, pills, an ointment, or a spray.
  • Beta-blockers "block" the chemical or hormonal messages sent to your heart that make it work harder. 
  • Calcium channel blockers can help to keep your arteries open and reduce your blood pressure by relaxing the smooth muscle that surrounds the arteries in your body.
You may need to try a number of these medicines before you find the one that works best for you.

See also on this site:

Updated July 2015

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