Objective To evaluate the function and synchronization of left atrial in patients with chronic heart failure(CHF) by two dimensional-speckle tracking imaging (2D-STI) and real-time threedimensional echocardiography(RT-3DE).Methods Thirty-two healthy controls and twenty-nine patients with CHF were studied.The mean strain and strain rate during systole,early and late of diastole(mSs,mSe and mSa,mSRs,mSRe and mSRa) were measured at each left atrial wall by 2D-STI.From the volume-time curve of RT-3DE workstation,the maximum volume (LAVmax),the minimum volume(LAVmin),the volume before contraction(LAVp) of left atrial were acquired.Accordingly,the total,passive and active ejection fraction could be calculated.The synchronization parameters derived from 2D-STI and RT-3DE were the dispersion of time to peak strain and time to the minimum volume (T-SD and Tmsv-16-SD).The index of volume and time were corrected by the body surface area and interval of R-R,respectively.The correlation were analysed betwee them.Results () Comparing between two groups,the mSs,mSe and mSa were shortened and the mSRs,mSRe and mSRa were slower in CHF group (P ＜ 0.05).② All the index of volume were gradually increasing from control to CHF group,but the LATEF,LAPEF and LAAEF were just the reverse,with all parameters had significant difference between two groups (P ＜0.05).③ The synchronization parameters were significantly higher from control to CHF group by the two kinds of skills (P ＜0.05).Comparing with 2D-STI,the indexes of synchronization were bigger and the asynchronization rate of CHF group were higher by RT-3DE.④The indexes of synchronization had a negative correlation with the strain rate and the ejection fraction,but had a positive correlation with the index of volume.Conclusions The function of left atrial are reduced in patients of CHF,there are asynchronization.2D-STI and RT 3DE may paly important roles in the evaluation of function and synchronization of left atrial.The relevance ratio of the left atrial asynchronization are higher from the RT-3DE than 2D-STI.