Teresa,
Estrogen suppmentation such as the patch you mention can make things better, make things worse, or make no difference at all. The only way to find out is to try. Sadly, that's the case with many things about Migraines.
On the subject of preventives, I understand that heart arrhythmia complicates things, but many of the medications that are being used effectively for Migraine prevention were originally developed to treat heart issues. You can find a listing of preventive medications, listed by class in our article Migraine preventive medications - too many options to give up!
With the complications in your situation, you might find it best to consult a Migraine specialist and for him or her to consult with your other doctors. It's important to note that neurologists aren't necessarily Migraine and headache specialists. Take a look at the article Migraine and Headache Specialists - What's So Special? If you need help finding a Migraine specialist, check our listing of Patient Recommended Migraine and Headache Specialists.
If you'd like some additional support, come join our discussion forum. You'll need to register again once there because it's a separate membership database, but you can use the same member name, email address, and password that you used here. You can find our forum at http://forums.healthcentral.com/discussion/migraine/forums.
Good luck,
Teri