Clinical Outcomes of Left Bundle Branch Area Pacing in Comparison with Right Ventricular Septal Pacing in Patients with High Ventricular Pacing Ratio ≥40%

Background: The aim of the present study is to compare the clinical outcomes between left bundle branch area pacing (LBBaP) and right ventricular septal pacing (RVSP) in patients with percent ventricular pacing (VP%) ≥40%. Methods: Fifty-four patients with VP% ≥40% were retrospectively studied, including 33 patients with LBBaP and 21 patients with RVSP. QRS duration (QRSd), interventricular mechanical delay (IVMD) and septal-posterior wall motion delay (SPWMD) were measured to evaluate ventricular synchrony. Heart failure hospitalization (HFH), pacing parameters, and complications were evaluated postoperatively and at follow-ups. Results: The mean follow-up duration of the study participants was 13.80 ± 4.47 months. In the LBBaP group, no significant differences were noted in paced QRSd, IVMD and SPWMD of the LBBaP capture and intrinsic-conduction modes, but the paced QRSd was narrower (QRSd, 110.88 ± 7.37 vs 132.90 ± 14.78 ms, P< 0.0001) and the IVMD and SPWMD were lower when compared with the RVSP group (IVMD, 28.16 ± 4.76 vs 40.28 ± 6.97 ms, P <0.0001; SPWMD, 43.68 ± 26.41 vs 97.94 ± 12.77 ms, P <0.0001). LBBaP was associated with better left ventricular function in comparison with RVSP during follow-ups (LVEDD, 47.09 ± 4.47 vs 51.28 ± 7.58, P = 0.017; LVEF, 64.81± 5.49 vs 60.44 ± 9.28, P = 0.041). Patients with LBBaP had lower occurrences of HFH than patients with RVSP (3.13% vs 27.78%, P = 0.034). Pacing parameters showed no differences between the two groups and remained stable throughout the study period. Conclusion: The results of this study suggest that LBBaP may be more suitable for patients requiring long-term high ventricular pacing ratio.