BACKGROUND AND OBJECTIVES: Diastolic heart failure (DHF) is defined as clinical evidences of heart failure, with a normal ejection fraction (EF) and abnormal diastolic function. However, the distinction between DHF and SHF is often difficult. Strain (S) and strain rate (SR) echocardiography can measure the regional myocardial function as a magnitude and rate of deformation. The hypothesis"myocardial velocity (Vel), S & SR can provide additional information for differentiation DHF from SHF"was assessed. SUBJECTS AND METHODS: 30 patients with symptomatic HF and low EF (SHF group) and 27 with symptomatic HF, and normal EF and diastolic dysfunction (DHF group) were enrolled. 37 age-and sex-matched control subjects were recruited. Conventional echo and regional indices (Vel, S and SR), measured at the mid septum and posterior wall, were obtained. RESULTS: Almost all clinical and echo indices of control were different between the two HF groups. The EF, LV mass, S' and DT in DHF were greater than those with SHF. The LA size, diastolic dysfunction grades; E, A, E/A, E', A' and E/E', were not different between the two HF groups. In the regional indices, the peak S (long axis: 12.0+/-5.4 vs. 17.6+/-5.9%, radial axis: 26.4+/-12.7 vs. 46.0+/-16.7%) and systolic Vel (long axis: 2.6+/-0.8 vs. 3.6+/-0.9 cm/s, radial axis: 2.1 (1.2 vs. 3.7+/-1.4 cm/s) with SHF were significantly lower than those with DHF. However, the SR of the two groups was not different. The best cutoff values of peak S were 13.7% (long axis) and 329% (radial axis), and the systolic Vel were 3.0 cm/s (long axis) and 2.8 cm/s (radial axis). CONCLUSION: The peak S and systolic Vel may be useful indices for differentiating DHF from SHF. A similarly decreased SR in the two HF groups suggests that DHF has decreased myocardial contractility, despite the normal EF.