Definition and Overview
A tilt table test or upright tilt testing is a basic diagnostic test used to determine the causes of postural hypotension, which is more commonly known as fainting, especially in cases where there is no suspected heart disease. The test is very straightforward, non-invasive, and does not require advanced equipment.
Who Should Undergo and Expected Results
A tilt table test is often recommended for people:
Who have fainted at least once without any obvious cause
Who are suspected of suffering from vasovagal syncope, a condition that refers to fainting spells that occur with or without accompanying symptoms, which may include sweating, nausea, and sudden weakness, usually due to a specific trigger. Most cases show that the cause of the condition can be positional tachycardia, cardiac arrhythmia, or a drastic change in blood pressure.
How Does the Procedure Work?
A tilt table test is often conducted by either a trained technician or a nurse, usually in an electrophysiology lab or a hospital or clinic.
This simple test is done by making the patient lie on a table for about 15 minutes with straps holding him in place, then tilting the table upwards until the patient is in a standing position while still attached to the table. This is done to simulate the act of moving from a horizontal orientation to a vertical standing position. The patient will then be held in a standing position for 45 minutes.
The entire test usually lasts for up to 90 minutes, if both parts are conducted, and up to 40 minutes, if only the first part is done.
Throughout the test, the patient’s heart rate and blood pressure are constantly monitored to evaluate how well the body responds to positional changes. This is made possible by placing electrodes on the patient’s chest, arms, and legs, as well as a blood pressure monitor on the arm or finger, prior to the start of the test. The electrodes are connected to an ECG or electrocardiogram machine to allow heart rate monitoring while the blood pressure cuff allows the attending doctor to monitor blood pressure levels throughout the test.
If any medications are needed during the test, these are usually administered through an IV line. Isuprel or isoproterenol is usually the medication used if the patient fails to exhibit any symptoms after 45 minutes into the test. The goals are to lower the patient’s diastolic blood pressure, increase the heart rate, and reduce his peripheral vascular resistance to trigger a vasovagal syncope. If the patient remains conscious, he will be kept under monitoring for up to 20 minutes more before the test is ended. However, if the patient faints while in an upright position, the table is immediately returned to a horizontal position. This is identified as the second part of the test.
A tilt table test usually requires no recovery period, allowing patients to go back to their normal activities right after the test.
Possible Complications and Risks
As a very simple, non-invasive test, a tilt-table test does not pose any serious risks to patients. Complications that may arise during the test are very rare, although some are still present. These include:
- Asystole, or when a person’s heartbeat pauses for a prolonged period
- Low blood pressure, which may also occur for a prolonged period
- Prolonged fainting, or when the patient does not gain consciousness immediately after returning to a horizontal position
These complications, however, easily go away either after the test or as soon as the table is put back to a horizontal position.
Also, not all patients who undergo a tilt table test experience fainting during the test. Some of them do not lose consciousness at all. This does not render the test ineffective; in fact, patients are often returned to the horizontal position as soon as changes in heart rate and blood pressure show that they are about to faint.
However, tilt table testing is not considered as safe for all patients. People who are unable to stand, are suffering from a fracture of the lower extremities, has severe anemia, or has had a recent stroke or heart attack are not allowed to undergo tilt-table testing.
- American Heart Association