Long-Term Effect of Septal or Apical Pacing on Left and Right Ventricular Function after Permanent Pacemaker Implantation

Background: Right ventricular (RV) pacing is associated with left ventricular (LV) dysfunction. However, the effects of RV pacing at different sites on both LV and RV function have rarely been studied before. We want to determine whether different RV pacing sites differentially affect LV and RV deformation by using speckle tracking echocardiography (STE). Methods: The subjects were 73 patients who had undergone dual-chamber permanent pacemaker implantation and did not have structural heart diseases. LV and RV global longitudinal strains (GLS) were measured using STE to determine subtle changes in LV function. Twenty-three patients without pacing after pacemaker implantation served as controls; 14 and 36 patients showed apical and septal pacing, respectively. Results: There were no significant intergroup demographic differences. LV biplane ejection fractions in the septal-and apical-pacing groups were significantly lower than those in the controls. The GLSLV values were similar between the control and septal-pacing groups, but they were lower in the apical-pacing group. Multivariate analysis revealed that cumulative pacing loads and apical pacing were independent factors associated with lower GLSLV values. The GLSRV values were similar between the control and apical-pacing groups; however, they were lower in the septal-pacing group. Conclusion: We concluded that patients with septal pacing have significantly higher GLSLV and more modest decreases in GLSRV values than patients with apical pacing. Thus, septal pacing may be not necessarily preferable in patients without significant heart disease undergoing dual-chamber permanent pacemaker implantation. (Echocardiography 2013;30:812-819)