Check out a list of recommended doctors for POTS in the U.S., Canada, the UK and Australia plus links to other lists.
https://www.facebook.com/notes/dysautonomia-postural-orthostatic-tachycardia-syndrome-pots/list-of-recommended-doctors-updated-93016/750344044988804
https://www.facebook.com/notes/dysautonomia-postural-orthostatic-tachycardia-syndrome-pots/list-of-recommended-doctors-updated-93016/750344044988804