Left bundle branch area pacing is a feasible technique for HF and bradyarrhythmia

Left bundle branch area pacing (LBBAP) is a feasible primary pacing technique for patients with heart failure (HF) or bradyarrhythmia. The MELOS study is the largest multicentre, observational study to report on the efficacy and safety of this emerging pacing technique. Left bundle fascicular pacing (LBFP) and left ventricular septal pacing (LVSP) may result in better outcomes than proximal LBBP.

LBBAP includes LVSP, LBBP, and LBFP. Prof. Marek Jastrzębski (Jagiellonian University, Poland) and colleagues conducted the large observational MELOS study to assess the safety and efficacy of these pacing techniques in patients with HF or bradyarrhythmia (n=2,533) [1]. The mean age of the study population was 73.9 years, 57.6% were women, 27.5% had a history of HF, 22.4% had a left bundle branch block, and 87.9% were assessed prospectively. The main study outcomes were feasibility, success rate, and learning curve of the implantation procedure.

The learning curve suggested that approximately 150 to 200 procedures (any LBBAP procedure) needed to be performed to obtain the optimal success rate. In addition, the success rate of LBBAP techniques was 91.6% in patients with bradyarrhythmia and 76.8% in patients with HF. Predictors of failure were broad baseline QRS segments, low left ventricular ejection fractures, and HF. Prof. Jastrzębski added that these results indicate that patients who could benefit the most from the procedure are also the ones in whom the implantation is most difficult to be conducted successfully. Nonetheless, the capture threshold (0.77 V) and sensing (10.6 mV) suggest that the technique is adequate.

The obtained paced QRS segments (137–145 ms) and paced V6 R-wave peak time (77–83 ms) pointed to a physiological activation of the left ventricle. Furthermore, Prof. Jastrzębski mentioned that LBFP and LVSP are the dominant real-world techniques with 69.5% and 25.1% of the total LBBAP procedures and that these procedures lead to significantly better results than LBBP.

Complications were observed in 8.2% of the participants, most commonly being intraprocedural perforation of the interventricular septum (3.7%). Other complications included acute chest pain (1%), acute coronary syndrome (0.43%), coronary artery fistula (0.28%), and ST elevation in multiple leads (0.24%). According to Prof. Jastrzębski, complications were resolved without long-lasting sequelae.

Invited discussant Dr Angelo Auricchio (Cardiocentro Ticino, Switzerland) argued that LBBAP is promising, but that the success rate and complication rate need to be improved. “More training, better tools, more experience and consistency across centres are needed to evolve this technique. Next to that, guiding technology needs to be improved to support the implantation. Finally, large randomised-controlled trials should provide evidence on the safety and efficacy of LBBAP.”

1. Jastrzęvski M, et al. Multicentre European left bundle branch area pacing outcomes study: MELOS. Late-breaking science 1, EHRA 2022, 3–5 April, Copenhagen, Denmark.

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Posted on 1 June, 202213 June, 2022