Bariatric Surgery Evaluation and Assessment of Treatment Efficacy - Intervention Trial (BEAT-IT)

Inclusion Criteria: Signs and symptoms of HF according to the Europeans Society of Cardiology guideline; Left ventricular ejection fraction ≥40%; HFA-PEFF score ≥5 or HFA-PEFF score 2-4 in combination with positive stress test; Between 45 and 70 years of age; BMI 32-40 kg/m2; Paroxysmal or persistent AF with a rhythm control strategy; Willing to undergo both treatment strategies; Written informed consent. Exclusion Criteria: BMI ≥40 kg/m2; BMI <32 kg/m2; Patients unwilling or unable to sign informed consent; More than moderate mitral valve regurgitation/aortic valve regurgitation; More than mild mitral valve stenosis/aortic valve stenosis; Inadequate echocardiographic window for the assessment of LV mass index and/or the echocardiographic criteria needed for the HFA-PEFF score; History of myocardial infarction, myocarditis, any invasive cardiac intervention (e.g. surgery, percutaneous coronary intervention, ablation) or stroke, <3 months before inclusion; Scheduled for AF ablation; Complex congenital heart disease; Negative treatment advise from a specialized psychiatrist due to non-stabilized psychotic disorders, severe depression and/or personality disorders; Patients unable to care for themselves or who are unable adapt to inherent lifestyle changes following bariatric surgery; Any medical condition that limits life span <2 years; Diseases requiring long term use of anti-inflammatory treatments; The use of medication associated with substantial effects (>5 kg) on body weight.