From challenge to proficiency: decoding the learning curve of left bundle branch area pacing in heart failure patients

Background

Left bundle branch area pacing (LBBAP) is a promising physiological pacing technique but remains technically demanding. Data on learning curves and their impact on procedural outcomes are limited.

Purpose

To evaluate the learning curve for LBBAP implantation with respect to procedural success, radiation exposure and procedure duration over consecutive implantations.

Methods

LBBAP implantations at a single centre were retrospectively analysed. Success was defined as confirmed left bundle branch area capture on ECG as follows: QRS morphology transition during threshold testing, r-prime in V1, V6RWPT <90ms or V6-V1 interpeak interval >40ms. Procedural parameters included success rate, radiation dose, and procedure duration. Logistic regression and temporal trend analysis were used to evaluate changes in performance over time.

Results

Eighty (n = 80) patients (mean age 75.5 ± 10.6 years; mean BMI 27.7 ± 5.1 kg/m²; 75.0% male) with a mean LVEF of 36.4 ± 8.4% and a baseline QRS duration of 153.9 ± 23.1 ms were included (n = 46 lumenless leads, n = 34 stylet-driven leads) consisting of new implantations (n = 39) and upgrades (n = 41). There were two operators involved in the study, operator A (OP-A) with 61 (76.3%) cases, operator B (OP-B) 19 (23.7%) cases.

Learning curve modelling demonstrated increasing implantation success in the early phase (Figure 1). Combined operator data showed a plateau after approximately 60–70 cases, with probability of success of 82.8% after one third of cases and 86.3% after 80 cases. OP-A exhibited a steeper learning curve with an indication of plateau formation towards the end of the cohort, reaching 88.2% success after one third of cases and 90.3% after 61 cases. OP-B showed a continuously rising curve without reaching a plateau in this dataset, with success rates of 71.4% after one third and 88.9% after 19 implantations. Mean implantation duration for OP-A after one half of implantations was 108.7 ± 24.7min; after 61 cases 99.8 ± 26.1min, while remaining stable and shorter (79.5 ± 28.0min) for OP-B. Mean implantation duration decreased with both groups combined from 100.7 ± 32.0 min to 93.8 ± 28.0 min. No temporal trend was observed in radiation dosage. A plateau was reached early in the stylet-driven leads (20-30 cases) compared to the lumenless leads which did not reach a plateau yet in this cohort.

Conclusions

LBBAP shows a clear learning curve with improving success rates and shorter procedure duration over time. A performance plateau was reached after approximately 60–70 cases. Stylet-driven leads demonstrated a faster learning curve than lumenless systems. Radiation exposure remained stable. Factors influencing the learning curve may include technical advancement, patient selection, differences between primary implantations and upgrades and the overall sample size. These findings highlight the importance of growing operator experience to achieve optimal LBBAP outcomes.learning curve of LBBAP implantation