This study is to assess the effectiveness and safety of cryoballoon ablation comparing with medical therapy in patients with atrial fibrillation and heart failure with different ejection fraction categories.

Subjects with atrial fibrillation and heart failure with different ejection fraction categories are devided to either an anti-arrhythmic drug or cryoballoon catheter ablation.

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.

Diagnosed with symptomatic paroxysmal or persistent atrial fibrillation：defined as at least two symptomatic episodes in the last six months prior to enrollment.