What is a tilt table test, and how does it work?

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“Syncope” is the medical term for fainting. The tilt table test allows doctors to acquire information about people’s syncope.

If a person regularly experiences syncope and doctors have ruled out other causes, they may recommend a tilt table test. This test changes a person’s position — from lying down to upright — while they are strapped in place.

This change in position may cause the person to faint, and doctors will monitor the person’s blood pressure and ECG readings. This can help them determine what causes the syncope.

A person experiences syncope when there is reduced blood flow to their brain. This causes loss of consciousness and loss of postural control. A tilt table test can sometimes determine the underlying cause of syncope.

Potential causes of syncope include:

• Arrhythmia: This is an irregular heartbeat. The body may not receive enough blood flow when someone has an arrhythmia.
• Vasovagal syndrome: Also called vasovagal syncope, this is fainting that results from a sudden decrease in blood pressure or heart rate.
• Heart disease: Structural heart disease, such as an enlarged heart or problems with the heart valves, may block blood flow and cause fainting.
• Heart attack: A heart attack damages the heart, reducing blood flow.
• Cardiomyopathy ventricular dysfunction: The heart ventricles fail or become weak and therefore have a reduced ability to pump blood around the body.

Several conditions, including a variety of cardiac problems and certain blood flow disorders, can lead to syncope.

Tilt table tests can help doctors determine the underlying cause. Tilt table tests are helpful when an individual:

• has experienced multiple episodes of syncope of unknown origin
• has experienced a single syncope of an unknown origin and sustained a traumatic injury
• experiences a single syncope of unknown origin without any preceding symptoms
• experiences a fall that may be due to syncope
• produces jerking movements during a syncope-like episode

Tilt table tests can also help doctors differentiate syncope from other conditions, such as epilepsy.

This section discusses the different stages of a tilt table test.

Before

Before the test, an individual should fast for a minimum of 4 hours.

This is because a tilt table test may cause loss of consciousness. In very rare cases, people can vomit and choke while unconscious. Fasting reduces the chance of vomiting.

The medical staff will explain what happens during the test and can answer any questions a person may have. They will discuss the risks of urinary incontinence and vomiting while unconscious.

Before the test, medical staff may ask a person to remove all jewelry, tight clothing, and clothes above the waist. They will provide a gown for the person to wear.

In preparation for the test, the individual should empty their bladder before lying on the table. Medical staff will secure them to the table using straps.

They will attach blood pressure (BP) monitors and electrodes to record changes.

They may insert an IV line so they can easily administer medicines and fluids if they need to.

During

The test begins with the individual lying on the table. This is the passive phase of the test. It should last 20–45 minutes.

Toward the end of the passive phase, medical staff may ask the person to take medication, which can make the person more sensitive to the tilt test.

The medication is usually a pill containing 0.4 mg of nitroglycerine. However, the staff may instead administer it through the IV line.

The medical staff then tilts the table upward, so the person is in an upright “standing” position. The person must remain in this position while staff monitor their BP and heart rate for at least 15 minutes.

After

Once the staff has obtained the results, the tilt table test will end. However, it may end earlier if, for instance, the individual loses consciousness. Staff may also end the test if the individual has prolonged low blood pressure.

Medical staff will be on hand to reassure the person after any loss of consciousness. A person who has fainted will have to stay lying down until their BP and ECG readings return to typical levels.

When the individual has recovered, medical staff may ask them to compare the experience to previous fainting episodes.

Tilt table tests are largely safe. However, some potentially serious complications can occur, including:

• choking on vomit
• stroke
• heart attack
• arrhythmia
• severe weakness for several hours after the test

Serious cardiovascular complications are most likely to occur in people with narrowed arteries.

Severe reactions are generally rare. Nonetheless, medical staff must have basic emergency training to perform a tilt test.

Side effects

There are some other non-serious potential side effects of the tilt table test. Headaches are common after the test.

According to a 2021 review published in the European Heart Journal, a tilt table test is unlikely to cause syncope in people without an underlying condition. But it may cause dizziness or lightheadedness.

A consensus statement published in Clinical Autonomic Research details how doctors collect results from the tilt table test.

The tilt table test helps determine whether changes in position cause loss of consciousness and why. If loss of consciousness does occur, doctors will make a note of it.

Doctors will ask their patients whether their loss of consciousness felt like previous episodes. They may also ask family, friends, or partners to be present during the test. These individuals can compare previous episodes to any test-induced loss of consciousness.

Doctors will combine this information with data from blood pressure and heart activity monitors. They must consider all this information when making a diagnosis.

Tilt table tests are useful for diagnosing the underlying causes of syncope.

For instance, some people faint after getting up from sitting or lying down. This is because their blood pressure suddenly drops. The phenomenon is called orthostatic hypotension. Tilt table tests are useful in determining whether someone’s syncope is due to orthostatic hypotension.

The tilt table test can also reliably detect postural orthostatic tachycardia syndrome (POTS).

POTS is a condition in which someone’s heart rate increases when they stand up. In some cases, this can cause syncope.

Doctors will move on to further testing if a tilt table test is positive. Several conditions can cause orthostatic hypotension and POTS.

Possible causes of orthostatic hypotension include:

• Parkinson’s disease
• diabetes
• anemia
• dehydration
• cardiovascular disease
• adrenal insufficiency

Similarly, POTS may arise for several reasons. For example, POTS sometimes occurs because of elevated adrenaline levels. In other cases, it occurs because of blood loss.

Both orthostatic hypotension and POTS can arise as a result of a lack of physical fitness.

This section answers some frequently asked questions about the tilt table test.

What causes a positive tilt table test?

The change from lying down to upright may lead to an atypical response of the nervous and circulatory systems, resulting in a decrease in blood pressure.

What medication is given during a tilt table test?

If the test produces a decrease in blood pressure, medical staff will return the person to the lying position to recover. They will not administer any medication.

If the test does not lead to a decrease in blood pressure, medical staff may give a person nitroglycerin under the tongue or via IV to increase their sensitivity or provoke a response.

How accurate is a tilt table test for POTS?

Tilt table tests can reliably detect POTS in those who have it.

A tilt table test involves strapping a person to a table and moving it from a lying position to upright. This can help doctors identify the underlying cause of syncope.

The test can also help distinguish syncope from other causes of loss of consciousness.

In the vast majority of cases, this test is very safe.

Possible side effects of the test include headache, dizziness, and lightheadedness.