Introduction and aims: Several studies have demonstrated that the worsening of glucose tolerance is associated with an increased cardiac energetic expenditure. A validated echocardiographic estimate of this function is the myocardial mechano-energetic efficiency index (MEEi), a parameter of the amount of blood ejected in 1 second by each gram of the left ventricle mass (ml/s*g^-1). MEEi is held to be a strong predictor of cardiovascular events, especially heart failure and short-term trials show an amelioration of MEEi after sodium-glucose cotransporter-2 inhibitors (SGLT-2i) treatment. The aim of our study was to evaluate whether there were any differences of the MEEi after a sustained treatment with an SGLT-2i, dapagliflozin, in patients with type 2 diabetes (T2D). Methods: T2D patients with stable coronary artery disease (CAD), enrolled in our randomized controlled trial DAPAHeart, have been followed up for 4 years after the placebo group started therapy with dapagliflozin at the end of the study. The patients were subjected to an echocardiographic evaluation before and after the 4 year-treatment. Results: The dapagliflozin treatment has been maintained stable during the 4-years and the patients were metabolically well balanced, at the baseline and throughout the study. By normalizing the results for the ventricular mass, no significant changes (p=0.94) were observed in the MEEi before (0,323 ml/s*g^-1) and after the 4-year treatment with dapagliflozin (0,322 ml/s*g^-1). Conclusions: Treatment with the dapagliflozin preserved the MEEi up to 4 years. The present study suggests that MEEi preservation, despite the presence of CAD, might contribute to the cardiovascular protection observed with large SGLT-2i trials. Further studies are needed to clarify the mechanisms by which dapagliflozin preserves MEEi.