Endothelial function is closely related to the hemostasis , vascular tone, and organ perfusion in cardiovascular system, and its dysfunction would cause overactivation of the coagulative system to induce thrombus formation. So we study the relationship between the endothelial function and atrial fibrillation.

Inclusion Criteria:

• Lone AF patients and normal controls

Exclusion Criteria:

• DM, hypertension, hyperlipidemia, smoking, pregnancy,