To investigate whether fibroblast growth factor 23 can be used to predict recurrence after catheter ablation for atrial fibrillation and to provide an objective basis for the clinical selection of the optimal patients for catheter ablation.

Atrial fibrillation, which can result in stroke and thromboembolism in an approximately 5-fold increased risk, has been a great burden to health care system with the aging of population. Catheter ablation is the most promising treatment of atrial fibrillation. However, the recurrence rates of AF after catheter ablation are high, ranging from 20%-60%. Therefore, non-invasive predictors for AF recurrence after catheter ablation is necessary to select the optimal patients for this procedure.

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.

This research is going to recruit 200 consecutive patients with a history of atrial fibrillation for 180-360 days who intend to undergo catheter ablation. The day before catheter ablation, serum FGF-23 level will be detected. Echocardiogram and left atrial CT scan will also be performed on the day before catheter ablation. All patients will be routinely follow up in the outpatient department by cardiologists every month for 1 year. If patients complain about palpitations, fatigue, or other symptoms related to arrhythmia, Holter monitoring will be performed. Patients will also be advised to see their doctor anytime they have these symptoms and to undergo a 12-lead ECG examination or 24-hour Holter monitoring. In asymptomatic patients, 24-hour Holter monitoring or 7-day cardiac event recording will be performed every three months after the procedure. The endpoint for follow-up is the recurrence of atrial fibrillation, which is considered to be any episode of AF/AFL/AT after a blank period of 3 months after the procedure of catheter ablation. Those who develop recurrence of AF during follow up will be assigned to recurrence group, and those who do not develop recurrence of AF during follow up will be assigned to non-recurrence group. Comparison of the serum FGF-23 level between the two groups will be carried out in order to investigate the relationship between serum FGF-23 level and the recurrence of AF.

Inclusion Criteria:

• Have a history of atrial fibrillation for 180 to 360 days
• Provide written informed consent, having understood the benefits and risks of participation in the trial

Exclusion Criteria:

• Significant structural heart disease (including symptomatic coronary heart disease; prosthetic mitral or tricuspid valve; congenital heart disease where abnormality or its correction prohibits or increases the risk of ablation)
• Atrial Fibrillation precipitated by other diseases (such as thyrotoxicosis)
• Severe dysfunction of liver or kidney
• Diabetes
• Malignant tumor
• Inability or refusal to provide written informed consent for the study

This research is going to recruit 200 consecutive patients with a history of atrial fibrillation for 180-360 days who intend to undergo catheter ablation. Atrial fibrillation is diagnosed according to guidelines; Patients with structural heart disease; renal or hepatic impairment; neoplastic disorders; atrial fibrillation precipitated by other diseases such as thyrotoxicosis; or diabetes will be excluded.