What is the Pott's tilt test (Head Upright Tilt Table test)?

From the Guidelines

The Pott's tilt test, also known as the Head Upright Tilt Table test, is a diagnostic tool used to evaluate and manage syncope, particularly vasovagal syncope (VVS), and not a physical examination technique for posterior cruciate ligament (PCL) injury in the knee. The test involves a series of steps, including a supine pre-tilt phase, tilt angle, passive phase, and drug provocation phase, as outlined in the guidelines for the diagnosis and management of syncope 1. The most recent and highest quality study recommends the following method for tilt testing:

• A supine pre-tilt phase of at least 5 minutes when no venous cannulation is performed, and at least 20 minutes when cannulation is undertaken
• A tilt angle between 60° and 70°
• A passive phase of tilt of more than 20 minutes duration and a maximum of 45 minutes
• Use of either sublingual nitroglycerin or intravenous isoproteranil for drug provocation if the passive phase is negative, with the duration of the drug-challenge phase being 15–20 minutes The test should be continued until complete loss of consciousness occurs or completion of the protocol, and it is considered positive if syncope occurs 1. Key points to consider when performing the tilt test include:
• Ensuring the patient is fasted for 2–4 hours before the test
• Using a tilt table with a short tilt-down time (<15 seconds) to minimize the duration of precipitated asystole
• Being aware of the potential risks and contraindications, such as ischaemic heart disease, uncontrolled hypertension, and significant aortic stenosis, particularly when using isoproteranil
• Correlating the results of the tilt test with the patient's clinical presentation to prevent false-positive results and to establish a diagnosis of VVS or other conditions, such as delayed orthostatic hypotension or pseudosyncope 1.

From the Research

Tilt Table Testing

• Tilt table testing (TTT) is used to study short-term blood pressure and heart rate regulation during orthostatic challenges 2.
• The test provokes vasovagal reflex in many syncope patients and is widely used to evaluate orthostatic syndromes and dysautonomia 3.

Pott's Tilt Test (Head Upright Tilt Table Test)

• The head-up tilt test, also known as Pott's tilt test, evaluates autonomic system responses to orthostatic stress 3.
• The test involves monitoring of heart rate and blood pressure, and can also include capnography and cerebral blood flow monitoring to expand its diagnostic yield 3.

Indications and Diagnostic Yield

• TTT may be indicated when the initial syncope evaluation does not yield a certain diagnosis, but raises clinical suspicion of reflex syncope, orthostatic hypotension, postural orthostatic tachycardia syndrome, or psychogenic pseudosyncope 2.
• The tilt test can detect common syndromes such as neurally mediated syncope, orthostatic hypotension, postural orthostatic tachycardia syndrome, hypocapnic cerebral hypoperfusion, and orthostatic cerebral hypoperfusion syndrome 3.