Effects synchrony of pacing in right ventricular septum and right ventricular apex on biventricular

Objective To evaluate the effects of pacing in right ventricular septum(RVS)and right ventricular apex(RVA) on biventricular synchrony.Methods Fifty patients with permanent pacemaker implanted were divided into right ventricular septum pacing group(RVS)and right ventricular apex pacing group(RVA)according to the ventricular leads position.The QRS duration of the ECG,left ventricular ejection(LVEF),septal-to-posterior wall motion delay(SPWMD)and the interventricular mechanical delay(IVMD)were compared before and after operations.Results There were no significant differences in LVEF,SPWMD and IVMD by echocardiography between the two groups before operation.The mean QRS duration of RVS didn′t change dramatically,but the mean QRS duration of RVA was significantly longer than that of preoperation and RVS group.After three months follow up,the LVEF decreased,the SPWMD and IVMD increased dramatically in RVA group but didn′t change statistically in RVS group.Conclusions The RVA pacing disturbs the ventricular electrical and mechanical synchrony.Comparison with RVA,RVS pacing shows the advantages of shorter depolarization time,keeping the normal ventricular activation sequence and better mechanical performance.RVS pacing is more physiological than the RVA pacing.