Hi Allyson,
You've had 4 tests -- were all 4 of them Tilt Table Tests? If so, that's a lot!
Or were these some other kind of test?
I know that doctors can do a very simple test for POTS. They just have the patient stand still for 5 -10 minutes and look for increased heart rate. There may also be some change in BP. But this simple office heart rate test won't necessarily be abnormal for patients who have NMH (Neurally Mediated Hypotension, aka, neurocardiogenic syncope and other names). Some patients need a Tilt Table Test (aka, Head Up Tilt, HUT) in order to show any abnormal readings.
My BP drop never shows up in any of the office standing tests that I've had over the years. But a dramatic BP drop (my BP suddenly plummets to just about nothing, something not measurable) happened to me on two different tilt table tests. My symptoms generally start after a few minutes whether I'm standing or on the tilt table. But it takes between 20-30 minutes before the huge BP drop happens.
[FYI - My symptoms include nausea, dizziness, cold sweat, blurred vision, desire to move around or sit, and an increased heart rate but not always enough to be POTS, and others I've probably forgotten. These are all pre-syncope symptoms even though I never actually faint unless I'm on the tilt table test. ]
So this has me wondering, what test has your doctor done 4 times that has been negative 3 out of 4? Just curious to know what kind of tests doctors are doing these days.