Atrial Fibrillation (A Fib) By L Brent Mitchell, MD, Libin Cardiovascular Institute of Alberta, University of Calgary Reviewed / Revised Jan 2023 View Patient Education Etiology Classification Symptoms and Signs Diagnosis Treatment Key Points More Information Topic Resources Atrial Fibrillation CHA (2)... HAS-BLED Bleeding Risk Score Atrial fibrillation CHA2DS2-VASc Score HAS-BLED Tool for Predicting... Overview of Atrial Fibrillation Atrial fibrillation is a rapid, irregularly irregular atrial rhythm.