Acute Impact On Left Ventricular Systolic Synchrony And Global Systolic Function In Patients With Different Right Ventricular Site Pacing By Real-time Three-dimensional Echocardiography

Background Traditional right ventricular apex pacing is very popular in clinical becausepacemaker electrode can be located easily and dislocation rate is low. But in recent years, domestic and foreign relevant research shows that the long-term right ventricular apex pacingcan result in abnormal ventricular muscle electrical and mechanical activity, thus affecting theleft ventricular systolic synchrony and systolic function. Right ventricular outflow tractpacing as a new pacemaker technology is applied in clinical in recent years, because rightventricular outflow tract pacing site is closer to normal cardiac transmission path, it can obtainmore physiological cardiac conduction sequence. Acute impact on left ventricular systolicsynchrony and global systolic function in patients with different right ventricular site pacingremains to be further research. Real-time three-dimensional echocardiography as a newultrasound technique applied to clinical in recent years can compare left ventricular systolicsynchrony and left ventricular global systolic function of left ventricular wall16segmental inthe same cardiac cycle.Objective To evaluate acute impact on left ventricular systolic synchrony and globalsystolic function in patients with different right ventricular site pacing by real-timethree-dimensional echocardiography (RT-3DE).Methods60patients with DDD mode cardiac pacemakers were divided into two groupsaccording to different pacing site: RVOT pacing group and RVA pacing group. Patients intwo groups were evaluated before operation and1week after the operation by RT-3DE toobtain full volume images, and those images were analyzed by the Qlab8.1software. Someparameters including global and16-segmental volume-time curves (VCTs), dispersion of timefrom the start of electrocardiographic QRS wave to the point of minimal regional volume for16,12, and6left ventricular segments (Tmsv16-SD, Tmsv12-SD, Tmsv6-SD), maximaldifference of time to minimal regional volume for16,12and6left ventricular segments(Tmsv16-Dif、Tmsv12-Dif、Tmsv6-Dif), and left ventricular end-diastolic volume (LVEDV),left ventricular end-systolic volume (LVESV), stroke volume (SV), left ventricular ejectionfraction (LVEF) were measured respectively. Finally, compared the above parameters useSPSS17.0. Results1.There were no difference in age、gender、 heart rate、 left ventricular ejectionfraction between RVOT pacing group and RVA pacing group (p>0.05).2. There were nodifference in left ventricular systolic synchrony parameters and left ventricular global systolicfunction parameters between RVOT pacing group and RVA pacing group before operation(p>0.05).1week after the operation, the left ventricular systolic synchrony parametersincluding (Tmsv16-SD、Tmsv12-SD、Tmsv6-SD、Tmsv16-Dif、Tmsv12-Dif、Tmsv6-Dif)of RVA pacing group were significantly prolonged compared with before (P<0.05)and RVOTpacing group (P<0.05), but left ventricular systolic synchrony parameters of RVOT pacinggroup were not changed compared with before (P>0.05).3. The left ventricular global systolicfunction parameters including (LVEDV、 LVESV、SV、LVEF) were not changed (P>0.05)in RVA pacing group and RVOT pacing group.Conclusion1. RVA pacing could reduce left ventricular systolic synchrony in the earlydays of pacemaker. Compared with RVAP, RVOT pacing is closely accordance withphysiological pacing．2. RVOT pacing and RVA pacing did not reduce left ventricular globalsystolic function in the early days of pacemaker.3. RT-3DE is an accurate and objectivemethod to evaluate left ventricular systolic synchrony and global systolic function.