What is atrial fibrillation, or A-Fib? (James Roth, MD) James Roth, MD, electrophysiologist, describes atrial fibrillation, or A-Fib. Dr. Roth is part of the Froedtert & the Medical College of Wisconsin Arrhythmia Program. Featured in this Video Medical services Atrial Fibrillation (AFib) Treatment