This study aims to assess the impact of 24-week treatment of dapagliflozin in type 2 DM(diabetes mellitus) patients on diastolic dysfunction. Primary endpoint is assessing the impact of 24-week treatment of dapagliflozin in type 2 DM patients on subclinical diastolic dysfunction assessed by supine bicycle diastolic stress echocardiography. Secondary endpoint is assessing the impact of 24-week treatment of dapagliflozin in type 2 DM patients on functional capacity, he impact of 24-week treatment of dapagliflozin in type 2 DM patients at resting diastolic function. This is single-center, randomized, double-blind, placebo-controlled, parallel-arm intervention study.