Objective:To assess left ventricular systolic dssynehrony for heart failure patients with QRS Complexes<120ms by tissue velocity imagine (TVI). Methods:Eighteen normal subjects (Group Control) and twenty heart failure patients with ejection fraction (EF)≤45% (measured by Simpson method) and QRS complexes<120ms (Group CHF) were enrolled in the study. First

left ventricular tissue Doppler velocity curves were acquired along left ventricular apex viwe in each segment of different walls. After the lime to peak myocardial systolic contraction (Ts) was measured

the standard deviatio and maximal difference of Ts of the 12 left ventricular segments were calculaled (Ts-SDandTsmax-min). Furthermore

the duration from the beginning of QRS complexes to that of systolic wave (S)——Q-Sb was measured

total synchronicity index(TSI) and each regional synchronicity index (RSI) were caleulated. Result:Ts-SD、Tsmax-min and TSI in Group control and CHF were(8.5±4.3)ms vs(39.2±11.5)ms、(22.2±12.6)ms vs(111.5±28.9)ms、(9.4±2.9)ms vs(23±6.6)ms(P<0.0001). Conclusion:Left ventricular systolic dyssynchrony also exists in heart failure patients with QRS complexes<120ms. QRS duration can not be used as a determinant to assess left ventricular systolic dyssynchrony. On the other hand. TVI can assess left ventricular systolic dyssvnchrony precisely.