Lupus and heart problems

I have Lupus and my ANA is 1:1280.  It has been active for a year and a half and we have not been able to get it under control so far.  I have had to go to the hospital twice in the last two months.  Both times I stayed four days.  One time my sodium and potassium were extremely low and the second time my heart rate was around 170 when I stood up or walked a short distance (any type of activity).  After three days and many tests the cardiologist said my heart was very strong but I have vasculitis.  He has put me on digoxin and motoprolol both of which I have to monitor and take smaller doses of because the dose he wanted me on lowers my blood pressure too much.  I still have high heart rates at time, usually when I am moving around.  My Internest has me on 10mg. Prednisone, Celebrx and 50mg. Imuran.  The Cardiologist tells me this will go away when the lupus is under control.  I am concerned because he originally said I was fine and was releasing me from the hospital and then my Internest came in and said you can't go home with such a high heart rate.  Somewhere inbetween the two and the Cardiologists P.A. vasculitis came up.  It has been since January 13th. and I am still unable to do almost anything other than sleep or sit around.  I am worried they missed or misdiagnosed something.  He didn't see the vasculitis in the catscan or the unltrasound.  I feel they are guessing.  Is vasculitis common "around the heart" for lupus patients?  I can't find but one article online when I google vasculitis+heart+lupus and it doesn't sound good.  My family is pushing me to get more opinions.  Should I get another opinion?  Does anyone know anything about this.
Thank you
Joni