Objective To evaluate left ventricular systolic synchrony in patients with Ⅲ grade atrio-ventricular block(Ⅲ grade AVB) after pacemaker implantation by real-time three-dimensional echocardiography. Methods Methods Twelve patients with Ⅲ grade AVB implanted by VVI pacemaker, seven patients with Ⅲ grade AVB implanted by DDD pacemaker, twenty subjects with normal LV function were examined by Philips iE33 with a X3-1 probe. Results The minimal excursion in patients with Ⅲ grade AVB implanted by VVI pacemaker and DDD pacemaker was less than that in subjects with normal LV function (P <0.05) ,and two bull eyes displayed that some regional systolic timing delayed or ahead, but also some regional systolic excursion hypokinesis or dykinesis. Parameter index [including Tmsv 16-SD, Tmsv 12-SD, Tmsv 6-SD, Tmsv 16-Dif, Tmsv 12-Dif, Tmsv 6-Dif, Tmsv 16-SD (%), Tmsv 12-SD (%), Tmsv 6-SD (%), Tmsv 16-Dif (%), Tmsv 12-Dif (%), Tmsv 6-Dif(%)] of 17 segment time to minimal systolic volume in patients with Ⅲ grade AVB implanted by VVI pacemaker and DDD pacemaker was more than that in subjects with normal LV function (all P < 0.05). Conclusions Real-time three-dimensional echocardiography can rapidly evaluate left ventricular systolic synchrony in patients with Ⅲ grade AVB implanted by DDD pacemaker and VVI pacemaker. Key words: Echocardiography, real-time three-dimensional; Heart block; Cardiac pacing, artificial; Ventricular function, left