Where do I find testing for neuropathic OH in the Phoenix AZ area?

[Lbro]

After over 3 years of dealing with orthostatic hypotension symptoms, I am now looking at possible neuropathic causes.  In the past, I first thought it was excessive fluid in my legs, then I thought it was cardiac problems.  I have been seen by at least 6 cardiologists in the past 2 plus years, with no definitive diagnosis or treatment protocol other than .... yes you have OH.

I moved to a new town at 5,000 feet over a year ago, which didn't help matters.  My symptoms have been getting worse over the past 2 months.  In the past, my symptoms lessened thru the day, and by mid-afternoon, my symptoms of light-headedness were mild.  In the past two months, my symptoms have progressed to being full-time.  I like to use the elliptical trainer for exercise, and I can see the same worsening of symptoms
there.  It takes 5 minutes of very slow movement before my body starts to work better, and even then I may experience very fast a pulse rate some time later to the extent I have to step off the machine to recover.

In searching the internet, I found that my symptoms closely relate to the condition called neuropathic orthostatic hypotension, which is also called autonomic neuropathy, or AN.  The other terminologies that I think match are nOH, and NDAN.  At any rate, I've been looking for treatment centers in the Phoenix/Scottsdale and surrounding areas.  The only one I've found so far is Honor Health.  I see they do tilt table testing, which I think is a first step toward evaluating my condition.

I would be very interested in any and all comments anyone out there has to offer.
Thank you.