The Clinical Investigation Of The Influence Of RVA Pacing Or RVOT Pacing To Ventricular Synchronism And Cardiac Function

Objective:To evaluate the left ventricular(LV) global and segmental myocardial systolic function in patients with permanent DDD/VVI pacemaker implantation by speckle tracking imaging and tissue Doppler Imaging.Methods:RVA pacing was conducted in19patients(12males and7females), with a mean age of (61.30±8.49) years, of whom had atriventricular block(AV block) or sick sinus syndrome(SSS), and underwent RVOT pacing was conducted in18patients (10males and8females), with a mean age of (62.95±9.72)years, of whom had atriventricular block or sick sinus syndrome. All patients were implanted DDD or VVI pacemaker.16±8months after installment of the pacemakers, the ventricular threshold and pacing impedance changes trend were collected to evaluate the feasibility of RVOT pacing; To compare the change of QRS duration,PPEI,APEI,LAD, IVSD, LVIDd, LVIDs and LVEF were measured by conventional2-Dimensional echocardiography; Speckle tracking imaging was used to measured and analyzed the average of SL and SR among LV18segments and left ventricle torsion parameters to ealuated the ventricular synchrony.Results:There were no diferences in threshold parameters between RVOT and RVA pacing;Compared with pre-implantation, the QRS duration were significantly changed after ventricular pacing both in RVA pacing and RVOT pacing (p<0.01). But the increment in RVOT pacing is less than RVA pacing;LAD and LVIDS (P<0.05)were larger and LVEF (P<0.01) was less in RVA pacing than in RVOT pacing, LVEF(P<0.01) was also less in RVOT pacing; Compared with RVA pacing, RVOT pacing is better in E/Ea and PPEI-APEI.Compared with RVOT the value of GLS were significantly decreased in RVA group(P<0.05).while no significant difference was found between RVOT and control group.The GSR of the pacing groups were both lower than control group in control group(P<0.05),but RVA group showed more decrease trend.The SL and SR of the LV myocardial segments close to the pacing sites in both pacing groups showed significant decrease compared with control group.The curves of torsion velocity in the pacing groups were obviously disorganized compared with control group.The Ptw,AVC-tw,MVO-tw and Torsion were generally lower after ventricular pacing both in RVA pacing and RVOT pacing than those in the control group (p<0.01).But there were no significant differences between RVA group and RVOT group and there were no statistical differences in Ptv,Putv,Tptv and Tutv among the three groups.Conclusion:1. With the active fixation endocardial lead in RVOT pacing is safety and feasibility.2. Compared with RVA pacing, RVOT pacing can provide smaller variation in the duration and morphology of QRS complex, more physiological depolarization vector.3. From the comparison of PPEI-APEI,SL,SR and Torsion both RVA pacing and RVOT pacing may impair LV systolic and diastolic function.But RVOT pacing can provide better ventricular synchronization and cardiac electric-mechnical synchrony.RVOT pacing can slow down the deterioration of cardiac function.4. Speckle tracking imaging techniques can be used to track spots that the movement speed, myocardial strain, strain rate and rotation of the Torsion of mechanical parameters, the technology for the study of the whole heart and local myocardial mechanical motion provide new quantitative method.