Hi Tigeress,

It sounds like your drug level may be at a toxic level which in turn may be causing the dizziness and sz. along with the rapid heartbeat. This happened to me a few times over the yrs. then my Dr. did a cbc (complete blood count) along with checking my drug levels and they found out it was toxic and I had the same problems as you did. I then was cut back on my meds and after about 4 days I was a little better.
I know when I started taking vimpat it caused me to have a rapid heartbeat and shortness of breath every now and then so I let me Dr. know and I found out it was the drug. You may want to speak with your pharmacist to find out the side effects of any of the meds you are taking.
I have also heard that heart problems can often lead into sz. and maybe you should see a heart specialist to be sure nothing is wrong. I wish you the best of luck and May God Bless You!

Sue