Can vaccinations trigger K9 Epilepsy attacks?

I have a 8 year old pure bred Mareema. She used to have epileptic attacks as much as twice a month. The vet said if I started medication it would have to continue for the rest of her life. Well I stopped taking her to the vet after my divorce and the attacks have seemed to stop all together. She has had one attack in two years and I'm afraid to take her back now fearing it's the vaccination or heart worm medicine causing it. I still order flea medicine from over seas (advantage) and that doesn't seem to be a trigger.

Could it be those medications and vaccinations or does Epilepsy not get triggered by something like that. I'm seriously afraid to risk her having those attacks again by getting her shots updated.