CD69 and atrial fibrillation: In order to determine whether immune excitation and multiplication of T lymphocytes exist in external blood of patients with AF, this study detected the content of CD69 and HLA-DR in external blood of patients with AF and robust people and discovered that the positive rate of CD69 associate with HLA-DR in CD3+ T lymphocytes in the external blood of AF was prominently larger than the rate in control.