atrial fibrillation coronary artery bypass cryosurgery ATRIAL FIBRILLATION Atrial fibrillation (AF) is a disorder of the heart characterized by rapid and chaotic beating of the atria and is the most prevalent cardiac arrhythmia, affecting four million patients in the Western World.  AF is one of the leading causes of stroke and short-term hospitalizations with 400,000 new cases annually.  Despite its prevalence, there are no current, practical clinical options to effectively and safely treat AF. Catheter ablation to resolve AF’s underlying cause, aberrant electrical signals originating on the left side of the heart near or within the pulmonary veins, has been restricted by safety concerns. As a result, the standard treatments for AF are limited to various costly drug regimens that offer only a palliative (non-curative) approach.