For me, Chocolate brings on the A Fib (couldn't resist the Easter chocolates everyone bought me) and then by taking some slow-release magnesium at bedtime, along with one extra blood pressure pill, and the A Fib is gone in the morning. Done this about 4 times now. Yes, I have a Hx of A Fib, have had the cardiac conversion (shock treatment) twice and am on Pradaxa to prevent blood clots. Any stimulant like coffee or caffeine brings it on for me. My A Fib all started after a non-cancerous tumor was discovered inside my heart and it was removed. That was 8 years ago. I'm 67 now.