Activating autoantibodies to the beta-1 adrenergic and m2 muscarinic receptors facilitate atrial fibrillation in patients with Graves' hyperthyroidism.

Objectives: We studied activating autoantibodies to beta-1 adrenergic receptors (AAbeta1AR) and activating autoantibodies to M2 muscarinic receptors (AAM2R) in the genesis of atrial fibrillation (AF) in Graves' hyperthyroidism.

Background: Atrial fibrillation frequently complicates hyperthyroidism. Both AAbeta1AR and AAM2R have been described in some patients with dilated cardiomyopathy and AF.