Aims The purpose of our study was to evaluate the feasibility and efficacy of cardiac resynchronization therapy (CRT) via left bundle branch pacing (LBBP-CRT) compared with optimized biventricular pacing (BVP) with adaptive algorithm (BVP-aCRT) in heart failure with reduced left ventricular ejection fraction ≤35% (HFrEF) and left bundle branch block (LBBB). Methods and results One hundred patients with HFrEF and LBBB undergoing CRT were prospectively enrolled in a non-randomized fashion and divided into two groups (LBBP-CRT, n = 49; BVP-aCRT, n = 51) in four centres. Implant characteristics and echocardiographic parameters were accessed at baseline and during 6-month and 1-year follow-up. The success rate for LBBP-CRT and BVP-aCRT was 98.00% and 91.07%. Fused LBBP had the greatest reduced QRS duration compared to BVP-aCRT (126.54 ± 11.67 vs. 102.61 ± 9.66 ms, P < 0.001). Higher absolute left ventricular ejection fraction (LVEF) and △LVEF was also achieved in LBBP-CRT than BVP-aCRT at 6-month (47.58 ± 12.02% vs. 41.24 ± 10.56%, P = 0.008; 18.52 ± 13.19% vs. 12.89 ± 9.73%, P = 0.020) and 1-year follow-up (49.10 ± 10.43% vs. 43.62 ± 11.33%, P = 0.021; 20.90 ± 11.80% vs. 15.20 ± 9.98%, P = 0.015, P = 0.015). There was no significant difference in response rate between two groups while higher super-response rate was observed in LBBP-CRT as compared to BVP-aCRT at 6 months (53.06% vs. 36.59%, P = 0.016) and 12 months (61.22% vs. 39.22%, P = 0.028) during follow-up. The pacing threshold was lower in LBBP-CRT at implant and during 1-year follow-up (both P < 0.001). Procedure-related complications and adverse clinical outcomes including heart failure hospitalization and mortality were not significantly different in two groups. Conclusions The feasibility and efficacy of LBBP-CRT demonstrated better electromechanical resynchronization and higher clinical and echocardiographic response, especially higher super-response than BVP-aCRT in HFrEF with LBBB.

Aims The aim of this study is to prospectively assess the feasibility and safety of left bundle branch pacing (LBBP) when compared with right ventricular pacing (RVP) during mid-long-term follow-up in a large cohort. Methods and results Patients (n = 554) indicated for pacemaker implantation were prospectively and consecutively enrolled and were non-randomized divided into LBBP group and RVP group. The levels of cTnT and N-terminal pro-B type natriuretic peptide were measured and compared within 2 days post-procedure between two groups. Implant characteristics, procedure-related complications, and clinical outcomes were also compared. Pacing thresholds, sensing, and impedance were assessed during procedure and follow-up. Left bundle branch pacing was feasible with a success rate of 94.8% with high incidence of LBB potential (89.9%), selective LBBP (57.8%), and left deviation of paced QRS axis (79.7%) with mean Sti-LVAT of 65.07 ± 8.58 ms. Paced QRS duration was significantly narrower in LBBP when compared with RVP (132.02 ± 7.93 vs. 177.68 ± 15.58 ms, P < 0.0001) and the pacing parameters remained stable in two groups during 18 months follow-up. cTnT elevation was more significant in LBBP when compared with RVP within 2 days post-procedure (baseline: 0.03 ± 0.03 vs. 0.02 ± 0.03 ng/mL, P = 0.002; 1 day post-procedure: 0.13 ± 0.09 vs. 0.04 ± 0.03 ng/mL, P < 0.001; 2 days post-procedure: 0.10 ± 0.08 vs. 0.03 ± 0.08 ng/mL, P < 0.001). The complications and cardiac outcomes were not significantly different between two groups. Conclusion Left bundle branch pacing was feasible in bradycardia patients associated with stable pacing parameters during 18 months follow-up. Paced QRS duration was significantly narrower than that of RVP. Though cTnT elevation was more significant in LBBP within 2 days post-procedure, the complications, and cardiac outcomes were not significantly different between two groups.

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