A tilt table test is a diagnostic procedure used to investigate unexplained blackouts (syncope) and near-blackouts (presyncope) by reproducing the conditions that cause a drop in blood pressure or heart rate when a person moves from lying to standing. It is a safe, non-invasive test performed in a supervised cardiac or neurology unit.
How the test works
The patient lies flat on a motorised table and is secured with straps. After a period of rest, the table tilts to bring the patient to a near-upright position (usually 60 to 80 degrees). Heart rate and blood pressure are monitored continuously throughout. The patient remains in this position for up to 45 minutes, or until symptoms occur. In some protocols, a medication (such as glyceryl trinitrate or isoprenaline) is given to provoke a response if the initial phase is negative.
What it can diagnose
The tilt table test is primarily used to diagnose vasovagal syncope (also called neurocardiogenic syncope), in which an exaggerated reflex response causes the blood pressure and/or heart rate to fall suddenly, resulting in a blackout. It can also help identify postural tachycardia syndrome (PoTS) and orthostatic hypotension (a persistent drop in blood pressure on standing).
After cardiac arrest
In a small proportion of cardiac arrest survivors, particularly those whose arrest had no obvious structural or arrhythmic cause, a tilt table test may be performed to investigate whether a vasovagal or autonomic mechanism contributed to the event. However, in most survivors the primary investigation pathway focuses on arrhythmia and structural disease rather than vasovagal causes.
The experience
The test is generally well tolerated, though some patients find the prolonged upright tilting uncomfortable. If syncope occurs during the test, the table is immediately returned to a flat position, which rapidly restores blood pressure and consciousness.
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