Atrial Functional Mitral Regurgitation Response In Mitral Loop Cerclage Annuloplasty (AFRICA Study)

Inclusion Criteria: * NYHA(New York Heart Association) Class III - IV * and, Functional Mitral Regurgitation 3+ (Moderate/Severe) or 4+ (Severe) in spite of optimal medical treatment. (For optimal medical treatments, ①ACE inhibitor or angiotensin receptor blocker ②β-blocker ③ aldosterone antagonists should be given for at least 3 months unless the subject has contraindication for each drug) * and, Chronic Atrial Fibrillation in electrocardiography (Persistent AF or Permanent AF) Exclusion Criteria: * Primary Mitral Regurgitation * LV ejection fraction lower than 30% * Pulmonary arterial pressure ≥ 60mmHg * End-diastolic Left ventricular dimension ≥ 70mm * Subjects with functional MR who need CABG or AVR performed * Pre-existing stent in a coronary artery that is deemed to be in direct contact with the path of mitral loop cerclage along coronary sinus * Subjects who have functional MR caused by aortic valve disease * Subjects who have uncontrollable hyperthyroidism * Subjects who have severe TR due to primary valve leaflet disease * Anomaly of Coronary Sinus * Pre-existing devices in coronary sinus such as Implantable Cardioverter Defibrillator and Pacemaker * 2:1 Atriventricular AV block or higher AV block and ventricular tachycardia * Subjects with primary MR * Subjects who cannot be screened by cardiac CT * Subjects who have possibility of coronary artery pinching even with Mitral Loop Cerclage system judged by cardiac CT * Subjects who do not have septal vein or have unsuitable septal vein anatomy by cardiac CT or venogram * Subjects who have thrombosis and embolism * Creatinine ≥2.0 mg/dL * Subjects who have coagulation disorders * Subjects who are unable to take anti-platelet agents * Pre-existing devices such as Implantable Cardioverter Defibrillator and Pacemaker * Subjects who are pregnant, or lactating, or plan pregnancy during the clinical trials * Subjects who are participated in other clinical trials within 1 month of enrollment * Subjects who are deemed not to be eligible in this study by physician's discretion