CAB Versus Medical Therapy in Patients With AF and HF With Different EF Categories

Inclusion Criteria: * Diagnosed with symptomatic paroxysmal or persistent atrial fibrillation：defined as at least two symptomatic episodes in the last six months prior to enrollment. * At least 18 years old and not older than 80 years old. * Able and willing to give informed consent. Exclusion Criteria: * History of AF treatment with class I or III AAD, including sotalol, with the intention to prevent an AF recurrence. However, patients pretreated with above AAD for less than 7 days with the intention to convert an AF episode are allowed. * Previous left atrial ablation. * Previous cardiac surgery including prosthetic valves. * Permanent pacemaker or defibrillator implant. * Second degree type II or third degree AV-block or a pattern of left/right bundle branch block. * History of previous myocardial infarction or percutaneous intervention during the last 3 months. * Any history of previous transient ischemic attack, prolonged reversible ischemic neurological deficit, and/or stroke. * Known intracardiac thrombus formation. * Pulmonary vein stent. * Known cryoglobulinaemia. * Active systemic infection. * Hypertrophic cardiomyopathy. * Life expectancy is ≤1 year. * Reversible cause of atrial fibrillation (eg, hyperthyroidism or alcoholism). * Abnormal long or short QT intervals, signs of Brugada syndrome, known family history of inherited ion channel disease, and/or arrhythmogenic right ventricular dysplasia. * Chronic obstructive pulmonary disease with detected pulmonary hypertension and/or any other evidence of significant lung disease. * Contraindication for oral anticoagulation. * Pregnant women or woman of childbearing potential with inadequate birth control. * Women who are breastfeeding. * Any significant congenital heart defect corrected or not corrected; however, patent foramen ovale is allowed. * Thrombocytosis (platelet count \> 600,000/μL) or thrombocytopenia (platelet count \< 100,000/μL). * Untreated or uncontrolled hyperthyroidism or hypothyroidism. * Renal dysfunction with glomerular filtration rate \< 60 mL/min. * Unstable angina pectoris. * Symptomatic carotid stenosis. * Myxoma based on laboratory abnormalities. * Sarcoidosis. * Unwilling to unable to comply with the study procedure and follow-up schedule due to any disease condition. * Legal incapacity or evidence that the patient cannot understand the purpose and risks of the study, including inability to comply fully with study procedures and follow-up. * Employed by Medtronic, or the department of an investigator, or close-familial relative of an investigator. * Enrolled or planning to participate in a potentially confounding drug or device trial during this study.