Dysautonomia can be diagnosed by either a Cardiologist, or a Neurologist. Diagnosis is often elusive; requiring a visit to either an academic teaching hospital, or a Dysautonomia Specialist.
Neurocardiogenic Syncope is one form of Dysautonomia. Florinef is one of the more common treatments. If your doctor has already prescribed Florinef, it may well be in your best interest to give it a try. Though if you are nervous about the prospect of taking medication, you should let your doctor know about that as well. S/he may prescribe smaller doses, or have other recommendations for you. If you do end up taking Florinef, one of the side effects to be aware of is lowered potassium levels. I would recommend asking for an electrolyte level about a week or two into treatment. Some patients find that they require a prescription potassium supplement as well.
Increasing fluids, and sodium intake is one non-medicinal treatment. Gatorade G2, or Powerade Zero if you are watching sugar intake, are good options. There are many other options available for keeping hydrated, which I'm certain our community members can help with any recommendations. There are also salt tablets, which you can ask your doctor about. I haven't had much luck with them personally, but I know there are patients who have found them somewhat helpful.
Another non-medicinal treatment commonly used in our community is compression stockings. These garments, though often uncomfortable, increase blood pressure by constricting blood vessels in the legs. I think most of us have found prescription thigh-high compression to be the most helpful. It's usually recommended to start at a 30-40 compression, but some of our community members use higher compressions.
Florinef:
http://www.medhelp.org/drugs/Florinef-Acetate/show/5390
Autonomic Dysfunction & Dysautonomia Index:
http://www.medhelp.org/health_pages/Neurological-Disorders/Autonomic-Dysfunction--Dysautonomia-Index-Page/show/857?cid=196
Diagnosing Dysautonomia:
http://www.medhelp.org/health_pages/Neurological-Disorders/Diagnosing-Dysautonomia/show/827?cid=196
Dysautonomia Specialists:
http://www.medhelp.org/health_pages/Neurological-Disorders/Dysautonomia-Specialists/show/717?cid=196
Dysautonomia Treatments:
http://www.medhelp.org/health_pages/Neurological-Disorders/Dysautonomia-Treatments/show/171?cid=196