Autoantibodies in atrial fibrillation: actor, biomaker or bystander?

Atrial fibrillation (AF) is one of the most common arrhythmias in patients with congestive heart failure, although the underlying mechanism has still to be determined. There is increasing evidence to suggest that autoimmunity may play an important role in the pathogenesis of AF. To date, at least three types of autoantibody have been found in AF: the anti-myosin heavy chain autoantibody, the anti-M2 muscarinic receptor autoantibody and the anti-heat shock protein autoantibody. The question is: are these autoantibodies actors, biomakers or merely bystanders? How much knowledge do we have?