Inclusion Criteria:  At least one episode of atrial fibrillation* that is documented during the prior year by any kind of ECG recording. Diabetes mellitus type II was diagnosed. (HBA1c >6.5%) and are using oral hypoglycemic agents only At least 20 years old and not older than 80 years old. Normal ECG parameters when measured in sinus rhythm (QRS width ≤120 ms, QTc interval <440 ms, and PQ interval ≤210 ms in a 12 lead ECG) Able and willing to give informed consent.  Exclusion Criteria:  Any disease that limits life expectancy under 1 year Subject for another clinical trial within the past 2 months Under 20 years old or over 80 years old Pregnant women Lactating women Drug abuser Type 2 DM treated by recombinant insulin Diagnosis of Type 1 DM, MODY, or secondary DM HbA1c ≥12% or HbA1c <6.5% at diagnosis Previous treatment with any SGLT2 inhibitor Renal dysfunction (eGFR-CKD-EPI <30ml/min/1.73m^2) Chronic cystitis and/or recurrent genitourinary tract infections (3 or more in the last year) Unexplained hematuria at baseline study Systolic BP >180mmHg or diastolic BP >100mmHg at baseline study Systolic BP <95mmHg at baseline study Previous treatment with AF ablation Acute cardiovascular event [e.g., stroke, acute coronary syndrome (ACS), revascularization, decompensated HF, sustained ventricular tachycardia, return of spontaneous circulation (ROSC)] <8 weeks prior to baseline study Severe valvular disease or have prosthetic valve Treatment with chronic oral steroid (>30 consecutive days) at a dose equivalent to oral prednisolone ≥10mg/d, within the past 1 month History of any malignancy within 5 years Clinically profound hepatic dysfunction Clinically uncontrolled thyroid dysfunction Patients incapable of completing the trial due to any severe medical condition by clinical decision Patients with poor compliance (defined as 80 - 120%), except for reasonable situations judged by physician