Short-term Effects Of Right Ventricular Outflow Tract And Apex Pacing On Left Ventricular Systolic Synchronism And Function Assessed By Real-Time Three-Dimensional Echocardiography

Objective:To assess the short-term effects of left ventricular systolic synchronism and function between right ventricular out tract (RVOT) pacing and right ventricular apex (RVA) pacing using real-time three-dimensional echocardiography (RT-3DE). Methods:Thirty-six pacemaker patients enrolled this study, randomly divided into RVOT pacing group (RVOT group, n=19) and RVA pacing group (RVA group, n=17). The left ventricular ejection fraction (LVEF),the standard deviation to the point of minimal systolic volume among all 16 segments (Tmsv-16-SD) and the maximal difference to the point of minimal systolic volume among all 16 segments(Tmsv-16-Dif) were derived using the Qlab software at baseline and three months after implantation by RT-3DE. Results: There were no significant difference in baseline characteristics between two groups (P>0.05). Compared with baseline, Tmsv-16-SD and Tmsv-16-Dif were significantly incresaed after implantation in both two groups (P<0.05). LVEF, Tmsv-16-SD and Tmsv-16-Dif were not significantly different at 3 month after implantation between two groups(all P>0.05). Conclusions:Although there are producing unfavourable effects on left ventricular systolic synchronism both of RVOT and RVA pacing, there are not significantly affected on left ventricular systolic function in short-term. Compare with RVA pacing, RVOT pacing can't reduce the unfavourable effects on left ventricular systolic synchronism and systolic function in short-term.