A tilt table test (TTT), occasionally called upright tilt testing (UTT), is a
medical procedure often used to
diagnose dysautonomia or
syncope.
Patient
A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other health ...
s with
symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...
s of dizziness or lightheadedness, with or without a loss of
consciousness
Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
(
fainting), suspected to be associated with a drop in
blood pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressur ...
or positional
tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ( ...
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 that 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
Fast or FAST may refer to:
* Fast (noun), high speed or velocity
* Fast (noun, verb), to practice fasting, abstaining from food and/or water for a certain period of time
Acronyms and coded Computing and software
* ''Faceted Application of Subje ...
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 pressure 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 (as if standing). Most of the time, the patient is suspended at an angle of 60 to 80
degree
Degree may refer to:
As a unit of measurement
* Degree (angle), a unit of angle measurement
** Degree of geographical latitude
** Degree of geographical longitude
* Degree symbol (°), a notation used in science, engineering, and mathemati ...
s.
Sometimes, the patient will be given a drug, such as
glyceryl trinitrate
Nitroglycerin (NG), (alternative spelling of nitroglycerine) also known as trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily, explosive liquid most commonly produced by nitrating g ...
(nitroglycerin) 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 (usually from 20 to 45 minutes, depending on the facility or individualized protocol).
Diagnostic symptoms
A tilt table test is considered positive if the patient experiences symptoms associated with a drop in blood pressure or
cardiac arrhythmia
Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the Cardiac cycle, heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per mi ...
. 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
Blood vessels are the structures of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away fro ...
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
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in th ...
pooling in the legs and, to onlookers, the patient's lower extremities may appear blotchy,
pink
Pink is the color of a namesake flower that is a pale tint of red. It was first used as a color name in the late 17th century. According to surveys in Europe and the United States, pink is the color most often associated with charm, politeness, ...
, or
red.
Dizziness or lightheadedness are also likely to occur in susceptible patients. Tilt table testing could provoke fainting or syncope. It is the purpose of the test to provoke these symptoms, in order to aid in diagnosis. It may not be appropriate, or indeed even possible, to stop the test before fainting 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.
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
Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically giv ...
or a sympathomimetic drug like epinephrine or
ephedrine which will raise blood pressure and heart rate rapidly. In extreme cases, tilt table testing could provoke
seizures
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with los ...
or even cause the
heart to stop. The heart resumes beating normally upon being returned to a flat or head-down position.
A drop in blood pressure during the tilt table test is indicative of
orthostatic hypotension. A marked increase in heart rate in the absence of orthostatic hypotension is indicative of
postural orthostatic tachycardia syndrome.
See also
*
Dix–Hallpike test
References
External links
2004 European Society of Cardiology Guidelines on Management (Diagnosis and Treatment) of Syncope.
{{Peripheral nervous system tests and procedures
Diagnostic cardiology
Diagnostic neurology
Physical examination