GJA1 and atrial fibrillation: Dysfunction of the immune system leading to arrhythmia in patients with RA may have the following mechanisms: (1) crosstalk between immune cells and fibroblasts and/or cardiomyocytes, leading to fibrosis and thus atrial fibrillation; (2) immune cells directly participate in the electrical remodeling of leukocytes through gap junctions with CX-43 leading to atrial fibrillation; (3) the immune system can directly affect the specific ion channel function on the surface of cardiomyocytes through autoantibodies and/or inflammatory cytokines leading to atrial fibrillation (19–21).