Background: Most diabetic patients had silent ischemia and cardiac dysfunction that is usually observed in late phase of the disease, when it grows to be clinically obvious. We hypothesized that left ventricular dyssynchrony (LVDys) (or dispersion) is an early marker of myocardial involvement in asymptomatic early Type 2 Diabetes Mellitus (T2DM) patients. Aim: Therefore, we aimed to predict early markers of myocardial dysfunction in early T2DM using LVDys and left ventricular mechanical reserve (LVMR). Patients and methods: We examined 91 consecutive subjects with early T2DM with speckle tracking imaging to evaluate LVDys and with dobutamine stress to evaluate LVMR (defined as an exercised increased in global longitudinal strain (LVMRGLS) ≥ 2%). Our patients divided into two groups according to LVDys; Group1: with LVDys (n=49) & Group 2: without LVDys (n=42). Results: We found that 49 (54%) subjects in our cohort had resting LVDys (Ts-SD-12 >34.2 mSec). Global longitudinal strain (GLS) and strain rate were comparable at rest between patients with and without dyssynchrony. On the other hand LVMR was blunted in those with LVDys (p<0.001). We found that HbA1C, High sensitive-C reactive protein (hs-CRP) and left atrial volume index (LAVI) were inversely correlated with LVMR. Multivariate analysis showed that LVDys was the strongest predictors (p<0.001) for blunted LVMR. With Receiver Operating characteristic (ROC) curve analysis, we found that a Standard deviation of Tissue synchronization of the 12 left ventricular segments (Ts-SD-12) ≥ 36.5 mSec was the best cut-off value to predict blunted LVMR (AUC=0.89, p<0.001). Conclusion: The LVDys (Ts-SD-12) cutoff ≥ 36.5 mSec was the optimal value for prediction of impaired LVMR and might be an early marker of subclinical cardiac dysfunction and risk stratification of subjects with asymptomatic early T2DM patients with preserved LVEF. Keywords: Dyssynchrony, Contractile reserve, Mechanical reserve, Diabetes, Coronary flow, Subclinical cardiomyopathy