Left bundle branch pacing vs ventricular septal pacing for cardiac resynchronization therapy

Background The outcomes of left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) in patients with heart failure remain to be learned. Objective The objective of this study was to assess the echocardiographic and clinical outcomes with LBBP, LVSP, and deep septal pacing (DSP). Methods This retrospective study included patients who met the criteria for cardiac resynchronization therapy (CRT) and underwent attempted LBBP in 5 Mayo centers. Clinical, electrocardiographic, and echocardiographic data were collected at baseline and follow-up. Results A total of 91 consecutive patients were included in the study. 52 patients had LBBP, 25 had LVSP, and 14 had DSP. The median follow-up duration was 307 (208, 508) days. There was significant LVEF improvement in the LBBP and LVSP groups (35.9 ± 8.5% to 46.9 ± 10.0%, P <0.001 in the LBBP group; 33.1 ± 7.5% to 41.8 ± 10.8%, P <0.001 in the LVSP group), but not in the DSP group. A unipolar paced right bundle branch block (RBBB) morphology during the procedure in lead V1 was associated with higher odds of CRT response. There was no significant difference in heart failure hospitalization (HFH) and all-cause deaths between the LBBP and LVSP groups. The rate of HFH and all-cause deaths were increased in the DSP group compared to the LBBP group (HR: 5.10; 95% CI: 1.14-22.78; P = 0.033 and HR: 7.83; 95% CI: 1.38-44.32; P = 0.020, respectively). Conclusion In patients undergoing CRT, LVSP had comparable CRT outcomes compared to LBBP.