Impact of Dapagliflozin on DIAstolic Dysfunction in Type 2 Diabetic Patients

Inclusion Criteria: * Female and male aged 19\~75 years * Type 2 DM and had not reached adequate glycemic control with a stable dose of metformin, sulfonylurea, or both drugs before screening * HbA1c 7.0% \~ 10% at screening (Patients who take metformin only: HbA1C 6.5-10%) * Patients with ≥ grade 1 diastolic function (relaxation abnormality) at resting echocardiography * Patients provided with the written, informed consent to participate in this study Exclusion Criteria: * Type 1 DM (Fasting c-peptide ≤ 0.78ng/dL(or 0.26 nM/L)), secondary diabetes, gestational diabetes * History of diabetic ketoacidosis, hyperglycemic hyperosmolar status * Estimated glomerular filtration rate \< 60 mL/min/1.73m2 * History of chronic cystitis or recurrent urinary tract infection * Currently on loop diuretics * Currently on medication known to affect glucose metabolism (e.g. corticosteroids, immunosuppressants) * Abnormal liver function (AST/ALT \> x3 upper normal limit) * On weight loss program or taking weight loss medication * LV ejection fraction \< 50% at resting echocardiography * Uncontrolled hypertension (systolic blood pressure \>200mmHg and/or diastolic blood pressure \>110mmHg) * History of acute myocardial infarction, unstable angina, coronary artery bypass graft or stroke within 6 months * Inducible ECG abnormalities at exercise * Cardiomyopathy, significant valvular heart disease, or a significant arrhythmia * Patients who cannot perform supine bicycle stress echocardiography * Pregnant or lactating women * Subjects who the investigator deems inappropriate to participate in this study