A tilt table test, occasionally called upright tilt testing, is a medical procedure often
used to diagnose dysautonomia or syncope. Patients with symptoms of dizziness or lightheadedness,
with or without a loss of consciousness, suspected to be associated with a drop in blood pressure
or positional tachycardia are good candidates for this test.
The procedure tests for causes of syncope by attempting to cause syncope by having the
patient lie flat on a special table or bed and then be monitored with ECG and a blood
pressure monitor which measure continuous, beat to beat, non-invasively . The table then
creates a change in posture from lying to standing.
Preparations Before taking the test, the patient may be
instructed to fast for a period before the test will take place and to stop taking any
medications. On the day of the tilt table test, an intravenous line may be placed in
case the patient needs to be given medications quickly; however, this may influence the results
of the test and may only be indicated in particular circumstances. More recently, most investigators
monitor cerebral perfusion using mean flow velocity recording with transcranial Doppler
ultrasound in supine horizontal position, during and after head-up tilt. An 18 MHz
ultrasound transducer is placed on the temporal bone above the cheekbone, using headgear to
hold the probe in place. Procedure
A tilt table test can be done in different ways and be modified for individual circumstances.
In some cases, the patient will be strapped to a tilt table lying flat and then tilted
or suspended completely or almost completely upright. Most of the time, the patient is
suspended at an angle of 60 to 80 degrees. Sometimes, the patient will be given a drug,
such as Glyceryl trinitrate or isoproterenol, to create further susceptibility to the test.
In all cases, the patient is instructed not to move. Symptoms, blood pressure, pulse,
electrocardiogram, and sometimes blood oxygen saturation are recorded. The test either ends
when the patient faints or develops other significant symptoms, or after a set period.
Diagnostic symptoms A tilt table test is considered positive if
the patient experiences symptoms associated with a drop in blood pressure or cardiac arrhythmia.
A normal person's blood pressure will not drop dramatically while standing, because
the body will compensate for this posture with a slight increase in heart rate and constriction
of the blood vessels in the legs. If this process does not function normally in the
patient, the test could provoke signs and symptoms ranging from minor lightheadedness
to a very severe cardiac episode, depending on the person.
A common side effect during tilt table testing is a feeling of heaviness and warmth in the
lower extremities. This is due to blood pooling in the legs and, to onlookers, the patient's
lower extremities may appear blotchy, pink, or red.
Dizziness or lightheadedness are also likely to occur in susceptible patients. Tilt table
testing could provoke fainting or syncope; in fact, this is the purpose of the test.
It may not be appropriate, or indeed even possible, to stop the test before this occurs,
as the drop in blood pressure or pulse rate associated with fainting can come on in seconds.
This is why the patient's blood pressure and ECG should be continuously monitored during
the test. In extreme cases, tilt table testing could
provoke seizures or even cause the heart to stop. The heart resumes beating normally upon
being returned to a flat or head-down position. If at any time in tilt table testing a patient
loses consciousness, he or she will be returned to a supine or head down position and will
be given immediate medical attention, which could include being given fluids or perhaps
atropine or a sympathomimetic drug like epinephrine or ephedrine which will raise blood pressure
and heart rate rapidly. See also
Dix–Hallpike test References
External links 2004 European Society of Cardiology Guidelines
on Management of Syncope. University of Michigan: Tilt Table Testing
Head-Upright Tilt Table Testing Tilt Table Testing
Tilt Table Test information from Children's Hospital Heart Center, Seattle