A tilt-table is a test done to diagnose Vasovagal (neurocardiogenic) syncope. This condition may cause symptoms of nausea, lightheadedness, or passing out. It is an abnormal neurologic reflex
that causes the heart to slow down or the blood pressure to drop too low. This may be triggered by dehydration, stress,
after exercise, or may occur without warning. Patients with typical findings of Vasovagal syncope generally do not need
a tilt-table test, as the history alone is enough to diagnose the condition. The test is often used in patients
with unusual symptoms, those who do not respond to treatment, or those who have high-risk occupations.
The tilt-table test is performed by having the patient lie down on a table on his back.
The legs and chest are strapped down, and the table is tilted to the upright position (typically about 80 degrees), so the
patient is almost standing upright. The heart rate and blood pressure are monitored. This upright position places
a small stress on the body to maintain a normal blood pressure, as the legs are not moving to help return blood to the heart.
We typically observe patients in this position for 10 minutes, and then return to the lying position. Patients who are
very sensitive to the test will develop a fast heart rate followed by an inappropriately slow rate or low blood pressure.
Symptoms of nausea may also occur, and the test is considered positive.
If no reacton occurs, we repeat the test one more time after some medication is given.
Sometime an IV infusion of Isuprel is used, which simulates excess adrenaline from stress or exercise. We generally
do not use this medication any longer, and use nitroglycerin instead because of simplicity of use. Nitroglycerin dilates
the blood vessels, and increased the natural production of adrenaline reflexively. This will increase the chance the
patient will have an abnormal blood pressure reaction to the test. Although some normal patients may have an abnormal
tilt table test when done as above, generally a positive test indicates the diagnosis of Vasovagal syncope. A negative
test indicates that another diagnosis is more likely, although some patients with this condition will have positive test some
days, and a normal test other days.
It is important not to eat or drink anything for 4 hours prior to the test. During the
test, patients may develop symptoms of feeling ill, have lightheadedness, or actually pass out. If a slow heart rate
or low blood pressure occurs, the table is immediately placed flat. The heart rate and blood pressure will usually return
to normal very quickly, although some patients may pass out from very slow heart rate for up to 30 seconds or so.
