Fibroblast growth factor-23 (FGF-23) is a bone-derived hormone that plays a central role in phosphate homeostasis. Recent study showed that fibroblast growth factor 23 plays an important role in cardiac remodeling and is considered to be independently associated with the occurrence of atrial fibrillation. In this study, we are going to observe the relationship between the serum FGF-23 and the arrythmia recurrence after catheter ablation of AF.