DPP4 and diabetic cardiomyopathy: Hence, the primary aims of this review are (1) to highlight the importance of diastolic dysfunction in diabetic cardiomyopathy, and (2) to describe the impact of antidiabetic therapies including metformin, SGLT-2 inhibitors, GLP-1R agonists, and DPP-4 inhibitors on diastolic dysfunction in T2DM.