I would recommend posting in the dysautonomia community to try and get some help.
http://www.medhelp.org/forums/Dysautonomia-Autonomic-Dysfunction/show/266
I personally don't know of any specialists for this condition. You can search online for different hospitals that have well-known cardiac centers and then look up the doctor's specialties and ratings that are at those centers. After you find a doctor that seems really good, make an appointment to see them and discuss with them what the best option for treatment is for you. I know it's hard to find a specialist, but don't give up. You can also ask your general practitioner/regular doctor who they recommend that you see. I hope it all goes well. Good luck.