The primary purpose of this trial is to evaluate the impact of empagliflozin, as compared with placebo, in patients with diabetes mellitus or overweight, heart failure and atrial fibrillation.

A 24-month randomized, single-blind, placebo-controlled trial to investigate the efficacy of empagliflozin to reduce atrial fibrillation burden in patients with diabetes mellitus or overweight, heart failure and atrial fibrillation in which a rhythm control strategy is indicated.

Inclusion Criteria:

1. Age 18-80 years
2. Diabetes mellitus or Body Mass Index over 25 Kg/m2
3. Heart failure
4. New York Heart Association (NYHA) Functional Classification: II or III
5. Documented atrial fibrillation
6. Understands the nature of the study, treatment procedure and provides written informed consent
7. Willing to comply with specified pre-, post- and follow-up testing, evaluations and requirements
8. Expected to remain available for at least 24 months after enrollment

Exclusion Criteria:

1. Permanent atrial fibrillation
2. Current use or prior use of a sodium-glucose co-transporter (SGLT) 2 inhibitor or combined inhibitor of SGLT-1 and SGLT-2 (all the other antidiabetic drugs are permitted performing an accurate glycemic control)
3. Known allergy or hypersensitivity to any SGLT-2 inhibitors
4. History of ketoacidosis
5. Need or wish to continue the intake of restricted medications or any drug considered likely to interfere with the safe conduct of the trial
6. New York Heart Association (NYHA) Functional Classification: I or IV
7. Unstable angina
8. Presence of any disease that is likely to shorten life expectancy to < 1 year
9. Any cardiac surgery within three months prior to enrolment
10. Awaiting cardiac transplantation or other cardiac surgery within the next year
11. Myocardial infarction within 60 days prior to enrolment
12. Contraindications to oral anticoagulation
13. Active systemic infection or sepsis
14. Left atrial thrombus (e.g., transesophageal echocardiography, computed tomography and intracardiac echocardiography)
15. History of a documented thromboembolic event such as stroke or transient ischemic neurological attack in the three months prior to enrollment
16. Currently enrolled in another trial that has not completed the required follow-up period and would conflict with this study
17. Chronic liver diseases
18. Chronic kidney disease (creatinine clearance < 45 ml/min)
19. Pregnant or breast-feeding mothers
20. Any other clinical condition that might jeopardize patient safety during participation in this trial or prevent the subject from adhering to the trial protocol