Although I will gladly accept a detailed answer I do not have alot of
money this week - I will take what I can get and promise to tip what I
can(SORRY).  If all you provide me with are words to google this is
ok.

My wife is 25 years old.  She is 5'9 and weighs about 220 pounds.  She
reveiced multiple epidurals and eventually surgery on her lower back. 
Her last epidural was done without an xray(2 yrs ago).  After this
final epidural she started passing out(fainting).  Typically she would
complain the room would spin and it would get hot.  Her face would
look panicked and she would fall where she stood.  While she was on
the ground her eyes would roll back into her head and she would not
respond to sounds.  Her body & limbs would shake like she were riding
a bull(convulse).  She would continue to shake on the ground until I
shouted multiple times in her ear.  Although I am not positive I feel
this is what brings her out.  It is difficult to watch a loved one
convulsing on the ground and having no control.  These episodes seem
to last until I start yelling in her ear.  I let one go 50 seconds
once.  When she comes to she complains her body (muscles?) ache. 
However, she does not remember what happened.  Her heart rate
afterwards typically seems normal.  These episodes happen regardless
of time(Night/Afternoon/Day).
     Following the epidural they happened 1 - 2 times a day for a few
days then would stop only to come back in 4 - 5 days (one epidural
required a blood patch).  Sometimes blackouts would happen once a
week.  They seem to come and go as they choose.  PLEASE?  Doctors do
not seem to being all they can do?  I am afraid this could kill her. 
We have had multiple tests: EKG, EEG, Halter Moniter(I am not
confident it was successful) and a MRI with and without contrast. 
There are no answers!
     Recently after 4 weeks without issue she fainted again without
warning.  She complained of blurred vision this time.  The more
information someone could provide me with would be appreciated.  The
doctors seem to think this is all in her head.  When we think it is
gone it comes back.  I am afraid she will fall down steps, fall in the
street or fall when no help is available.  Possibly someone could use
the following symptoms & situation and give me some suggestions(not a
diagnosis) on what it might be.  Then I can research and discuss it
with our doctors:

They fainting started 2 years ago after an Epidural(I have difficulty
feeling this is not related).  1 epidural required a blood patch - I
think it is called

*She would complain: 'It is hot!' - sometimes she was sweaty(even when
it was cool), 'I feel sick'(to stomach)', 'I feel dizzy', 'the room is
spinning'.  She would look slightly pale & confused.

*After these complaints she would fall to the ground.  Her eyes roll
back into her hear.  Her entire body would 'buck' - convulse in uneven
motions.

*The first 10-15 seconds she does not respond.  I am not sure but I
think my yelling(screaming) in her ear is what brings her out.  I have
never let her convulse more than 60 seconds - but if I did not scream
in her ear I think she would

* The spells are not as frequent as they were 1 year ago.  When they
1st started they seemed the worst.

*When she comes to she does not remember - no memory of what happened.
 She has pain where she fell(bumped herself) and complains her muscles
hurt.

* When she is convulsing she does not feel pain.  I've watched her hit
her head on objects.

*Sometimes fainting occurs without any warning.  It occurs at
random(day/night). Her heart rate does not seem changed afterwards.

* Most recently she complained of blurred vision(only one time 3 days ago).

* She gets frequent headaches migraines(has all her life)

* No change in diet, meds, social arrangements, friends, stress or
anything we can put a finger on prior to fainting spells.

* Last epidural was done without an xray('blindly')

* If we argure she sometimes passes out.  Stress does seem to play an
occasional factor.

*It has been 4 - 5 months since they have happened daily.

* She was molested when she was younger and suffers from PTSD - I do
not feel this is relevant.

I apologize this was so lengthy.  I am in desperate need of any
suggested reading material or help.  I am not sure what to do.  I
Strongly feel the doctors are not doing all they can.  We live in
Indianapolis, Indiana.  There is so much information on the internet
on fainting, passing out, blacking out and so much technical
information I am hoping someone can help sort it with what I have
describe.

Sounds like Epilepsy... what did the Physician diagnose...was any
Cardiac Injury Panel administered (CIP) what were its results... also
if you are dissatisfied with your Physicians ability to help your
wife, see a more reputable one/Medical Centers (ER only) are one
source. :)

TonySchwartz, please keep in mind that am not a physician and your
doctor (or other ones) are the best equipped to analyze the problem.

Y'know, epilepsy was my first thought as well. Syncope from a purely
cardiac condition rarely includes convulsions and usually does not
involve memory loss, but petit and grand mal episodes both can.

[Just an aside-- a Holter monitor is a pretty smart piece of
equipment. It knows if it is hooked up incorrectly and if wires
detach. The results are generally quite reliable.]

I'd also look into transient high blood pressure. After that you've
got a battery of brain scans and blood flow tests to run through, cat
scans, that sort of thing, some of which you've tried.

The confusion before the episode, the convulsions, and the memory loss
all sound exactly like what a friend described her epileptic episodes
as. Can you ask your doctors for their opinions on that?

Best of luck to you and your wife.

I work at a hospital, and I would recommmend that you see a
neurologist as soon as possible.  They would be able to better test
your wife, rather than just a primary care physician (your family
Dr.).  Good luck.  I would bet with a few more tests and some blood
work, that a diagnosis would be found fairly quickly.