Left ventricular electromechanical asynchrony has been shown to predict cardiac events in patients with heart failure. This study investigated whether left ventricular asynchrony is present in patients with type 2 diabetes mellitus (DM) with no clinically evident heart disease and normal QRS durations. Asynchrony was evaluated in 24 patients with DM, 15 nondiabetic control subjects, and 20 patients with left bundle branch block (LBBB) due to cardiomyopathy serving as positive controls by conventional tissue Doppler imaging and by a novel method, echocardiographic phase imaging. Asynchrony was significantly higher in patients with DM than in controls and significantly lower than in patients with LBBB. This was shown by tissue Doppler imaging: the SD of time to peak myocardial velocity was 13 +/- 10 ms in controls, compared with 30 +/- 19 ms in patients with DM (p <0.01) and 68 +/- 28 ms in those with LBBB (p <0.001). Similar data were obtained using echocardiographic phase imaging: the SD of phase degrees was 25 degrees +/- 8 degrees in controls, compared with 44 degrees +/- 21 degrees in patients with DM (p = 0.02) and 76 degrees +/- 25 degrees in those with LBBB (p <0.001). Tissue Doppler imaging correlated with echocardiographic phase imaging (r = 0.79, p <0.0001) but was more time consuming (15.5 +/- 4.5 vs 4.5 +/- 2.2 min/patient, p <0.05) and showed higher intraobserver variability (5.6% vs 3.2%, p <0.05). In conclusion, this is the first study showing increased left ventricular asynchrony in patients with DM and no clinical evidence of heart disease.