I keep having blackouts and no one knows why. Could it be a seizure?

[Faerydust]

I have been diagnosed with Syncope, but no one knows what is causing it.  I have been to a cardiologist and neurologist.  I've had EKG's, 24/48 hour halter moniters, heart ultrasound, MRI (brain scan), and EEG.  They have found nothing structurally wrong with my heart and brain, but I keep having blackouts.  Whenever I have an episode I have shortness of breath, rapid heart rate, sweaty palms and feet, ringing in the ears, blurred and/or loss of vision, shaking all over, my arms and legs draw up, loss of voluntary movement, loss of speech, and sometimes vomiting.  I've never had an episode while in a doctor's care, so they cannot know for sure what it is.  They think it is some kind of seizure.

[Dr Sharma]

Hi there. You could be having a migraine syndrome of symptoms including fainting, speech problems, the loss of control over voluntary movements, tinnitus all can be due to migraine association or it could be seizure activity which should be assessed in the light of an EEG, postural hypotension.
Consult with your neurologist for a detailed assessment.
Take care.

[Londres70]

Was the EEG a sleep deprived EEG?  

Was Dysautonomia ruled out?  A Tilt-Table Test, Nerve tests-QSART/EMG/NCV should be done if not already.