This study was planned to research the relationship between systolic myocardial velocity (Sm) obtained by tissue Doppler imaging (TDI) and left ventricular ejection fraction (LVEF) measured according to conventional Simpson's method in healthy subjects and patients with heart failure (HF). Two hundred eight patients with HF whose LVEF < 50% (mean age 59 ± 11 years) and 187 healthy subjects (mean age 57 ± 11 years) were enrolled in this study. LVEF was measured and TDI recordings were obtained at the septal, lateral, inferior, and anterior of the mitral annulus, and Sm was measured. LV mean Sm was calculated. In patients with HF, a significant correlation was detected between LVEF and Sm (r = 0.71, P < 0.0001), while no relationship was found between these parameters in healthy subjects (r = 0.16, not significant). The cutoff value of Sm < 8 cm/s for identifying patients with LVEF between 30% and 49% had a sensitivity of 86%, a specificity of 93%, and a negative predictive value of 92%, and the cutoff value of Sm < 6.0 cm/s for identifying patients with LVEF < 30% had a sensitivity of 92%, a specificity of 84%, and a negative predictive value of 97%. The time required to calculate the LVEF was significantly longer than that of LV mean Sm (327 ± 98 sec vs. 110 ± 29 sec, P < 0.0001), and LVEF had higher inter- and intraobserver variability. LV mean Sm obtained by TDI, a parameter that is reproducible, easily obtained, reliable, and practical, can be used to evaluate LV systolic function in patients with HF. © 2008, the Authors.