Primary Autonomic Failure/Multiple sysyem Atrophy

I have recently been diagnosed with the above condition after 3months in a Major hospital. As I am unable to tolerate Beta Blockers, the Neurologist has prescribed zoloft for me to help with my racing heart and tachicardia,because he says it has the same affects on the parts of the brain as the beta blockers do. What do you think? They had established that I am not depressed etc. I do find the zoloft does dull the pain in chest and the heart beat not as noticible to keep me awake, night and day now. Could just all be a coincidence. As this is a long slow,self pacing process. Baby steps for now. I do not like the fogginess in the head but not sure if that is from the zoloft or the 10 seizures I was having per day, when taken to hospital, due to lack of blood flow and oxygen to the brain.
I do hope that you can give me some insight into these questions, as I believe education is the best way to move forward, now. Thanking you Jenn