The atrial fibrillation (AF) is the most common cardiac rhythm disturbance that is responsible for substantial morbidity and mortality independent of associated heart disease or other risk factors. Even in the absence of preexisting cardiovascular disease, AF remains significantly associated with excess mortality rates. The current unsatisfactory treatment for AF comes from lack of understanding of the pathophysiology of AF. The purpose of this study is to identify gene polymorphisms that confer susceptibility to atrial fibrillation. Patients with AF（N=500） and healthy volunteer（N=1000） without AF are enrolled in this study. Patients with coronary artery disease, severe valvular heart disease, cardiomyopathy or heart failure were excluded from the study.