poper,
What type of work-up have you had?
If you have not been seen by a doc for this, then you definitely need to pronto. They need to rule out any heart abnormality or panic attacks.
Actually fish oil has been shown to help with arrythmias as has magnesium in some instances.
If you have already had it checked out, let me know what the diagnosis was, and maybe I can offer further advice.
Keep me posted.
Take care,
Ryan