Comparing long-term effect of right ventricular septal versus apical pacing on left ventricular function

Background: Right ventricular (RV) apical pacing is the standard technique for permanent pacemaker implantation and is known to cause detrimental effects on left ventricular (LV) function in long term. Limited data are available on alternative pacing sites which may help preserve LV function. We aimed to compare the long-term effect of RV septal versus apical pacing on LV function. Materials and Methods: A total of 93 consecutive patients were enrolled, of whom 52 received RV apical pacing and 41 RV septal pacing over a period of 2 years. LV assessment was done at regular follow-up including measurement of LV ejection fraction (LVEF), left atrial volume index (LAVi), and 2D LV longitudinal strain. Clinical outcomes included all-cause mortality and heart failure-related hospitalization. Results: Over a median follow-up was 6 years with interquartile range of 4–9 years, LVEF in the apical and septal pacing group was 48.1% ± 10.3% and 51.5% ± 10.2%, respectively (P = 0.112). However, RV septal pacing was significantly better than RV apical pacing with respect to global longitudinal strain (−17.2 ± 2.0 vs. −15.1 ± 2.9; P < 0.001) and LAVi (in RV apical group and 35.5 ± 5.8 ml/m2 vs. 42.7 ± 5.8 ml/m2; P < 0.001). Clinical endpoints, however, did not differ between the two groups. Conclusions: Long-term RV septal pacing was associated with fairly preserved LV function and lesser adverse LA remodeling as compared to RV apical pacing. Larger randomized studies are required to demonstrate the beneficial effect of septal pacing on clinical cardiovascular outcomes.