Objective To evaluate left ventricular(LV) systolic synchrony and sequence in patients with premature ventricular complexes(PVCs) from right ventricular outflow tract (RVOT).Methods Thirty patients with frequent isolated PVCs from RVOT and 30 healthy subjects as control were included.Speckle tracking imaging (STI) was performed to assess the time-to-peak segmental systolic strain in longit udinal(TsL), circumferential (TsC) and radial (TsR) direction.The standard deviation (SD) of TsL,TsC and TsR of 18 LV segments were calculated respectively.All values of patients with PVCs were recorded during sinus beats(PVC-S) and PVC beats(PVC-V) respectively.LV systolic sequence in PVC-V was analyzed.Results Significant differences were observed in the SD values between the PVC-V and control subjects in three directions,as well as between the PVC-S and control subjects in circumferential and radial direction.In PVC-V significance difference was seen in TsL and TsR from apical to basal level,as well as in TsL and TsC in different walls.Conclusions LV systolic synchrony was demonstrated in patients with PVCs from RVOT during both sinus beats and PVC beats.Systolic sequence in PVC beats from RVOT exhibit certain rules.