I will do some interjecting here as well;
Treating foci in the field seems a little out of the norm for a paramedic, doesn't it? Aren't we treating the patient not the monitor? I mean, recognizing what the ailment is great, but what if you are wrong? Is your medical director going to stand by your decision? Stabilize and transport, don't play doctor.
Some of us have limited resources at our disposal, the hospital has more. Don't try to figure out why he went into VFib, just treat the vfib. Perhaps the pt. was taking GHb, or Efedrin(?), you just won't know the answer to that until you do blood tests.
Now don't get me wrong, I love to learn more and study emergency medicine to make me better in the field, but sometimes I think we over think a situation. Learning new stuff is scary! Appling it is dangerous.
Just my two cents!