Bariatric Surgery Evaluation and Assessment of Treatment Efficacy - Intervention Trial

Inclusion Criteria: 1. Signs and symptoms of HF according to the Europeans Society of Cardiology guideline; 2. Left ventricular ejection fraction ≥40%; 3. HFA-PEFF score ≥5 or HFA-PEFF score 2-4 in combination with positive stress test; 4. Between 45 and 70 years of age; 5. BMI 32-40 kg/m2; 6. Paroxysmal or persistent AF with a rhythm control strategy; 7. Willing to undergo both treatment strategies; 8. Written informed consent. Exclusion Criteria: 1. BMI ≥40 kg/m2; 2. BMI \<32 kg/m2; 3. Patients unwilling or unable to sign informed consent; 4. More than moderate mitral valve regurgitation/aortic valve regurgitation; 5. More than mild mitral valve stenosis/aortic valve stenosis; 6. Inadequate echocardiographic window for the assessment of LV mass index and/or the echocardiographic criteria needed for the HFA-PEFF score; 7. History of myocardial infarction, myocarditis, any invasive cardiac intervention (e.g. surgery, percutaneous coronary intervention, ablation) or stroke, \<3 months before inclusion; 8. Scheduled for AF ablation; 9. Complex congenital heart disease; 10. Negative treatment advise from a specialized psychiatrist due to non-stabilized psychotic disorders, severe depression and/or personality disorders; 11. Patients unable to care for themselves or who are unable adapt to inherent lifestyle changes following bariatric surgery; 12. Any medical condition that limits life span \<2 years; 13. Diseases requiring long term use of anti-inflammatory treatments; 14. The use of medication associated with substantial effects (\>5 kg) on body weight.