Objectives To assess the prevalence of systolic dyssynchrony of the left ventricular(LV)wails in patients of heart failure(HF)with a normal QRS duration by Doppler tissue imaging(DTI).Methods 20 patients of HF with a normal QRS duration and 20 healthy individuals were investigated with DTI to quantitatively analyze their pulsed-wave Doppler spectrum of basal and middle segments in six walls of left ventricle.The time between the onset of the QRS complex of the surface ECG and the onset of the systolic wave of pulsed-wave Doppler spectrum was measured(TS).LV systolic synchronization was assessed by the maximal difference(MD)in time of TS,the standard deviation(SD)and the coefficient of variation(CV)of TS in the all 12 LV segments.Results When a TS-MD of TS＞53.08 ms,a TS-SD of TS＞18.08 ms and a TS-CV of TS＞0.91(+1.65 SD of normal controls) was used to define significant systolic dyssynchrony,the prevalence of systolic dyssynchrony was 55.0%,55.0% and 55.0%,respectively,in the HF patients group,significantly gher than those in the normai control and the locations of delayed contraction of these patients were different.Conclusions LV systolic dyssynchrony could be commonly demonstrated by DTI in HF patients with a normal QRS duration.This finding will support the view about the possibility that more HF patients could benefit from cardiac resynchronization therapy.