Postural tachycardia syndrome may, either occur spontaneously or in some cases, be a late complication of traumatic brain injury.
What is the purpose of head-up tilt table testing?
Tilt table testing is done to see if being upright provokes a sudden fall in blood pressure (neurally mediated hypotension), an excessive increase in pulse rate (POTS) or fainting (neurally mediated syncope).
How is the test performed?
The patient lies on a stretcher-like support. Straps that are similar to seatbelts are attached around the abdomen and legs and the patient is tilted upright. The exact angle of the tilt varies and is usually between 60 and 80 degrees. The tilting goes on for up to 45 minutes. The patient is gradually tilted to an upright position until systolic blood pressure drops to 70 mm Hg or the appearance of orthostatic symptoms such as dizziness, lightheadedness, or faintness. The purpose is to hopefully reproduce the patient’s problem in a controlled laboratory setting. It may not be performed on all patients, such as patients with a persistent fall in blood pressure each time they stand up (orthostatic hypotension) because the blood pressure will fall progressively beginning as soon as the tilting starts.
What are the expected results for a patient with POTS?
Patients with POTS would be expected to have an excessive (>30 beats/minute) increase in heart rate during head-up tilt with little or no change in blood pressure (change <20/10 mm Hg).