Bi-atrial Versus Left Atrial Ablation for Patients With Rheumatic Mitral Valve Disease and Non-paroxysmal Atrial Fibrillation

Inclusion Criteria: * Age ≥ 18 years * Diagnosis of persistent atrial fibrillation(AF) or long-standing persistent AF by medical history and Holter monitoring (persistent AF lasting more than 7 days; long-standing persistent AF lasting more than 1 year). * Rheumatic mitral valve disease(RMVD) requires mitral valve surgery( RMVD was determined by history of acute rheumatic fever, valve morphology, echocardiographic findings and pathological diagnosis). * Consent to surgical ablation of AF Exclusion Criteria: * Paroxysmal AF * Degenerative or ischemic mitral valve disease * Evidence of active infection * Previous catheter ablation or surgical ablation for AF * Surgical management of hypertrophic obstructive cardiomyopathy * Absolute contraindications for anticoagulation therapy * Left atrial thrombosis (not including left atrial appendage thrombosis alone) * Chronic obstructive pulmonary disease(Forced expiratory volume in 1 second (FEV1)\<30% anticipated value) * Uncontrolled hypo- or hyperthyroidism * Mental impairment or other conditions that may not allow participants to understand the nature, significance, and scope of study * Left atrial diameter\>70mm * Right ventricular dysfunction (TAPSE\<16) or moderate to severe tricuspid regurgitation or pulmonary artery pressure (estimated by echocardiography) \>60mmHg * Coronary artery bypass grafting is required for participants with coronary heart disease * Previous cardiac surgery * Refuse to participate in this study