My Tilt Table Test for POTS
After a two month wait, I was finally getting my autonomic reflex screen (ARS) at UCLA, which does include a tilt table test. I was referred here by my cardiologist after all other routine tests he had ordered came back normal. The ARS is going to assess whether I have any autonomic nervous system dysfunction, and to see if it can explain some of my symptoms. I’m definitely lucky that I live in Los Angeles as these extensive tests are done only at three places: UCLA, a Mayo clinic, and Vanderbilt — at least that’s what the staff told me.
Before my appointment, I was sent a set of instructions to prepare for the ARS.
At least 48 hours prior, I had to avoid certain medications (an extensive list was provided), wine, beer, coffee, tea (including herbal teas), and caffeinated soft drinks
No eating or drinking anything 3 hours prior to the testing
Wear loose comfortable clothes
This was not in the instructions, but I would highly recommend getting a ride to and from your tilt table test. Also, if you become symptomatic during or after the test, knowing you don’t have to drive yourself home would be a major stress relief (not to mention be safer for you and everyone).
At my appointment, I was called in by a super friendly technician who would be running my test. Other places, may have a nurse or doctor who will run or be present at the test. First, I was strapped to a table and hooked up to a machine that constantly measures my heart rate and blood pressure throughout the entire test. At UCLA, the tilt table is one part of the comprehensive autonomic nervous system testing. The other tests that I had to complete were:
DEEP BREATHING: I had to breathe as slowly and as deeply as I can for one minute while my heart rate and blood pressure are measured. This is to evaluate the parasympathetic cardiovagal functions by looking at the changes in the instant heart rate provoked by “deep” breathing. This test needs the valsalva test to determine if there is cardiovagal impairment.
VALSALVA: I had to take a deep breath and blow out against resistance for 15 seconds while my heart rate and blood pressure are measured. This evaluates the sympathetic adrenergic and parasympathetic cardiovagal functions. This test with deep breathing determines cardiovagal impairment, and with the tilt table test determines sympathetic impairment.
SUDOMOTOR (QSART): It’s a test that assesses the small nerve fibers that are involved in sweating. Several electrodes filled with acetylcholine are placed on different areas. A small current is turned to stimulate the sweat responses. For some it may be uncomfortable, but for me it was just a slight tingling burning sensation. The one by my ankle stung the most. I believe most use this test to see if you have any small fiber nerve damage, but it can be used to show any disturbances of the autonomic nervous system and some pain disorders.
The tilt table test is the gold standard for diagnosing postural orthostatic tachycardia syndrome (POTS). For this test, the technician told me that I would be lying down for 10 minutes and if I had any symptoms to tell him. After 10 minutes, the table will tilt up to a standing position. I would remain in this position for another 10 minutes and periodically the technician would ask if I had any symptoms. I wasn’t too symptomatic during the test and honestly thought I didn’t have POTS.
Two weeks later, to my surprise, I got a confirmed diagnosis for dysautonomia and POTS. The current diagnostic criteria for POTS is a heart rate increase of 30 beats per minute (bpm) or more, or over 120 bpm, within the first 10 minutes of standing, without orthostatic hypotension. I’ve seen different definition for orthostatic hypotension cut-offs. But the most common is at least a decrease in systolic blood pressure of 20 mmHg or a decrease in diastolic blood pressure of 10 mmHg within 3 minutes of standing. [For children and adolescents, the heart rate increase is ≥40 beats/min]
I’m still trying to accept that I got any sort of diagnosis. It’s validation that there is something off with my body and I did not imagine it all in my head. It is a bit disheartening that it’s not something that is fixable. But all the struggles I’ve gone through with this condition has made me the person I am today, and I wouldn’t trade that for anything.
I hope you found this post helpful! If you have any questions about these tests, I’m here to answer!