Atrioventricular Node Ablation and Conduction System Pacing in Patients With Well Controlled Permanent Atrial Fibrillation (AF), Heart Failure and Preserved Ejection Fraction: Heart Rate Regularization Versus Medical Rate Control

Inclusion Criteria: * Permanent atrial fibrilation \> 6 months * Preserved Left Ventricular Ejection Fraction ≥ 50% * ≥ 1 heart failure hospitalization in the previous year * NYHA (New York Heart Association) score ≥ 2 * Presence of at least one of the following criteria related to diastolic dysfunction: * E/e' ratio \> 9 * Left Ventricular mass \> 95 g/m2 (female) or \> 115 g/m2 (male) with h/R ratio \> 0.42 * NT pro BNP (B-type Natriuretic Peptide) \> 365 pg/mL or BNP (B-type Natriuretic Peptide) \> 105 pg/mL * Narrow QRS ≤ 120 ms * Average heart rate ≤ 110/min on 24 hours Holter monitoring * Age over 18-year-old * Capacity to understand the nature of the study, legal ability and willingness to give informed consent * Patient covered by a social insurance * Effective contraception and a negative pregnancy test in women of a childbearing age Exclusion Criteria: * Patient eligible for atrial fibrilation catheter ablation * Life expectancy \< 12 months * Severe chronic kidney disease (estimated Glomerular Filtration Rate ≤ 20 ml/1,73 m2) * Severe respiratory disease (severe chronic obstructive pulmonary disease with Gold ≥ 3 and/or chronic oxygen therapy) * Class III obesity (Body Mass Index ≥ 40) * Confirmed or suspected infiltrative cardiomyopathy (amyloidosis, sarcoidosis, Fabry disease, others) * Obstructive hypertrophic cardiomyopathy * Previous implanted devices (Pacemaker / Implantable Cardioverter-Defibrillator / Cardiac Resynchronization Therapy) * Other indication for pacemaker implantation * Indication for implantable cardioverter-defibrillator * Ambulatory ≤ 50% of time * Pregnant women * Breast-feeding women