Background/Objectives: Prior research has identified a significant association between heart disease and metabolic-dysfunction-associated steatotic liver disease (MASLD); however, the underlying mechanisms are unclear. This study aimed to identify predictive biomarkers associated with grade I left ventricular diastolic dysfunction (LVDD) in patients with type 2 diabetes mellitus (T2DM). Methods: This single-center, cross-sectional study evaluated 73 T2DM patients for grade 1 LVDD and MASLD using 2D echocardiography, tissue analysis, spectral color Doppler, and Fibromax. Results: This study analyzed 50 patients (mean age 58.0 ± 11.3 years) with a median diabetes duration of 7 years, abdominal obesity (mean body mass index (BMI) 34.4 ± 5.9 kg/m2), and a mean HbA1c of 7.9 ± 1.5%. The prevalence of grade I LVDD, fibrosis, mild steatosis, moderate-to-severe liver steatosis, mild MASLD, and moderate MASLD was 54%, 44%, 14%, 80%, 43%, and 34%, respectively. Regression analysis revealed that grade 1 LVDD was positively associated with age, Fibrotest, α2-macroglobulin, epicardiac adipose tissue (EAT), and negatively associated with lateral s', E wave, E/e', E/A, medium E', and septal e' (p < 0.05 for all). α2-macroglobulin > 1.92 g/L (area under the receiver operating characteristic curve (AUROC) = 0.782, sensitivity 70.4%, specificity 81.2%) and fibrotest score > 0.11 (AUROC 0.766, sensitivity 92.6%, specificity 56.2%) were significant predictors of grade I LVDD. Conclusions: Although the underlying mechanisms remain unclear, innovative non-invasive biomarkers, such as α2-macroglobulin or fibrotest, could concurrently indicate liver stiffness and the likelihood of grade I LVDD, an early, asymptomatic HF stage in T2DM patients.