I never had a problem with a-fib but Prednisone can certainly cause a-fib or make it worse.

Actemra might be an ideal medication for you. I was unable to taper off prednisone for more than 12 years after PMR was diagnosed. I had cardiovascular side effects from Prednisone. Actemra got me off Prednisone but it took time. It took me about a year to go from 10 mg to zero after Actemra was started. I noticed an improvement in my PMR symptoms in about 3 months. My rheumatologist says any biologic should be given at least 3 months to see if it will work for you or not.

I have been off Prednisone for almost 4 years. I still need a monthly infusions to Actemra to control my PMR symptoms. I don't have any concerning side effects from Actemra. Not only was I able to stop Prednisone, I was also able to discontinue five of my cardiovascular medications that were treating Prednisone side effects.

I sincerely hope Actemra will work for you as well as it does for me. You need to give Actemra some time to work because it doesn't work immediately like Prednisone does.