Glad you are able to have an outlet to express your experience with P.O.T.S.!
Saw on your blog you also were diagnosed with atrial fibrillation- have you read up on that yet?
I recently tried something myself that reduces heart rate- Bystolic and though I was on a low dose, it reduced my blood pressure too much, so I had to quit. I was diagnosed with P.O.T.S. and I.S.T. back in 2004. I have a sibling who was diagnosed more recently with P.O.T.S. and N.C.S. (though still conscious on a tilt table, but couldn't respond and vision was black and BP dangerously low). You mentioned in your blog about your having fainting- did the doctor not feel you had N.C.S.?
Some people do faint with P.O.T.S., while others do not. It must be scary for you to have times when you pass out. Have you bought a helmet yet to wear to try to prevent concussion in case of hitting your head in a fall? Some have, I think, who post on this dysautonomia forum.