I had a tilt table test and increased my HR by 30 beats (right on the edge of positive diagnosis). I asked to have the test stopped because of my horrible reaction - SOB, leg weakness, blurriness, dizzy, disoriented, etc - ended up crying. Anyway, my Neurologist diagnosed POTS because of my borderline reaction and my episode. I tried Mestonin and it helped for 4 months and then, stopped working. I, then, had a chemical EMG which was borderline, too, and had the same reaction as the Tilt Table Test. This time my cardiologist diagnosed POTS, too. I'm now trying the compression stockings, 3 L of water/day and increased salt intake. Not much of a difference. So I can try Midodrine, I am in the process of weaning myself off of a med I've been on forever for Fibromyalgia. The Fibro med is contraindicated in combination with Midodrine. Continuing the journey, as I have for 4 years.