SummaryBackgroundLeft ventricular (LV) diastolic dysfunction commonly is observed in individuals with type 2 diabetes mellitus (T2DM). We employed transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMRI) to investigate the hypothesis that LV diastolic dysfunction in T2DM is associated with poor glycemic control.MethodsForty subjects, 21 with normal glucose tolerance (NGT) and 19 with T2DM, were studied with CMRI and TTE to assess LV function. Early‐to‐late transmitral flow ratio (E/A) and deceleration time (DecT) were assessed with both modalities. Normalized (to body surface area) end‐diastolic volume (EDV/BSA) and normalized peak LV filling rate (pLVFR/BSA) were assessed with CMRI. Early transmitral flow velocity to septal velocity (E/e’) and isovolumetric relaxation time (IVRT) were measured using TTE. Dimensional parameters were normalized to body surface area (BSA).Results CMRI measurements demonstrated impaired E/A (1.13 ± 0.34 vs 1.62 ± 0.42, P < .001), increased DecT (174 ± 46 ms vs 146 ± 15, P = .005), as well as lower EDV/BSA (63 ± 10 vs 72 ± 9 mL/m2, P < .01) and pLVFR/BSA (189 ± 46 vs 221 ± 48 mL s−1 m−2, P < .05) in T2DM subjects. TTE measurements revealed lower E/A (1.1 ± 0.4 vs 1.4 ± 0.2, P < .001) and E/e’ (6.8 ± 1.5 vs 8.7 ± 2.0, P < .0001) with higher DecT (203 ± 22 ms vs 179 ± 18, P < .001) and IVRT (106 ± 14 ms vs 92 ± 10, P < .001) in T2DM. Multiple parameters of LV function: E/ACMRI (r = −.50, P = .001), E/ATTE (r = −.46, P < .005), pLVFR/BSA (r = −.35, P < .05), E/e’ (r = −.46, P < .005), EDV/BSACMRI (r = −.51, P < .0001), EDV/BSATTE (r = −.42, P < .01) were negatively correlated with HbA1c. All but E/e’ also were inversely correlated with fasting plasma glucose (FPG).ConclusionsImpaired LV diastolic function (DF) was found in T2DM subjects with both CMRI and TTE, and multiple LVDF parameters correlated negatively with HbA1c and FPG. These results indicate that impaired LVDF is inversely linked to glycemic control in T2DM patients.