Cycle-Length Mapping in Patients With Non-paroxysmal Atrial Fibrillation

Inclusion Criteria: 1. Patients who sign the informed consent forms, and allow to be followed. 2. Symptomatic AF refractory or intolerant to at least one Class 1 or 3 antiarrhythmic medication. 3. Patients with persistent/permanent AF (sustained beyond seven days, or lasting less than seven days but necessitating pharmacologic or electrical cardioversion). Persistent AF is defined as an AF episode which lasts longer than 7 days, Persistent AF which lasted longer than 12 months will be defined as long standing persistent AF. 4. Patients with age equal or greater than 20 years old regardless of gender. Exclusion Criteria: 1. The presence of an atrial or ventricular thrombus. 2. Patients who are allergic to or unsuitable for use with the contrast media. 3. Pregnant patients or patients who are unavailable to receive X-ray. 4. Patients with severe renal insufficiency. (Glomerular Filtration Rate \[GFR\] \< 15 mg/dl or under dialysis) 5. Patients had autonomic nervous system disorder (e.g. respiratory apnea). 6. Patients with age less than 20 years old or greater than 90 years old regardless of gender. 7. Contraindications to anticoagulation.