Integrative MD's would certainly be helpful...and maybe they would even work with other specialists or your GP. There are a few autonomic specialists out there also...for severe cases.
Not all have cardiac symptoms that actually need treatment, but by-in-large, cardiac involvement is one of the most common elements of autonomic dysfunction. Involving heart rate and BP, where sometimes medication or pacemaker is the only option that works. A cardio is the appropriate specialist IF treatment is needed. The heart itself may be okay, but function can be greatly affected.
http://en.wikipedia.org/wiki/Dysautonomia
Bobmar, It comes down to the cause (which is often never known) and severity of your symptoms. Your autonomic testing and clinical presentation would gauge what type of treatment you need. Some toxic dysautonomia can resolve on it's own (when toxin is eliminated, of course) in time...and from what I've read here, supplements will help this process and nerves to heal. Getting diabetes under control can also help secondary dysautonomia. However, some have permanent and debilitating dysautonomia from other causes, and it can be very difficult to treat.
Have you had any autoimmune work up?
What can you tell us about your PN...how is started, what meds you take, testing done, etc.
Have you had your B12 tested? What about diabetes testing?