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Syncope (blackouts)

What is syncope?

Syncope is the temporary loss of consciousness due to a sudden decline in blood flow to the brain. It may be caused by an irregular cardiac (heart) rate or rhythm or by changes of blood volume or distribution. Syncope can occur in otherwise healthy people. Symptoms include feeling faint, dizzy, or lightheaded (presyncope), leading to loss of consciousness (syncope).

Syncope can be caused by a variety of health problems, therefore it is important to determine the cause of fainting. Tilt table testing is a procedure that is used to diagnose the cause of fainting or syncope.

The most common type of syncope is called simple fainting or vasodepressor syncope. This type of fainting may be alarming to those who see it, but it is rarely life-threatening. It is caused by an unusual body response to position changes. Usually the heart rate and blood pressure increase when a person stands up. However, in some people, standing results in a sudden drop in blood pressure and heart rate. If the blood pressure falls too low, there is not enough blood flow to the brain and the person faints. When the person who faints is lying in a horizontal position, it is easier for the blood to reach the brain and the person wakes up.

The tilt table test is one test used to determine whether vasodepressor syncope is the cause of fainting. During the test, the individual is placed on a circle bed frame. This type of bed allows the person to be positioned lying flat and then upright without any effort on their part. The person’s blood pressure and heart rate are continuously measured. If the person does not faint with changes in position, further tests are performed. These include rubbing the side of the neck or administering certain medicines. The test is considered positive and stopped if the person faints or feels like they are about to faint. If the test is positive, medications or pacemakers may be prescribed by your doctor to treat the condition.