This study aims to:

1. Assess the consistency of LGE-MRI bi-atrial fibrosis and electroanatomical mapping of bi-atrial low voltage region
2. To evaluate the electroanatomical characteristics of different types of fibrosis (dense fibrosis, patchy fibrosis, etc.) in different locations of the left and right atrium;
3. To explore the correlation between preoperative and postoperative bi-atrial fibrosis and long-term recurrence in patients with atrial fibrillation.

Inclusion Criteria:

1. Adult patients (≥18 years old) who are willing to participate in this study and can sign informed consent;
2. Atrial fibrillation was diagnosed and catheter ablation was proposed

Exclusion Criteria:

1. Left atrial thrombus or left atrial appendage thrombus;
2. Severe chronic obstructive pulmonary disease (FEV1/ FVC<70%, FEV1<50% predicted value);
3. Absolute contraindications of anticoagulation therapy;
4. Currently pregnant;
5. Contraindications for LGE-MRI (claustrophobia, pacemaker implantation, eGFR<30ml/min for renal insufficiency, severe obesity, pregnancy, gadolinium chelating agent allergy, etc.);
6. refuse to participate in the study;
7. other physical or mental incapacity to participate in the study.

Adult AF patients who are planned to receive catheter ablation and have no contraindications of LGE-MRI

IPD will be shared under the permission of primary investigator