The Zwolle experience with left bundle branch area pacing using stylet-driven active fixation leads

Stylet-driven leads compared with lumenless leads for left bundle branch area pacing: a systematic review and meta-analysis

OBJECTIVE

Left bundle branch area pacing (LBBAP) is a novel physiological pacing method for treating left ventricular dyssynchrony. LBBAP is often delivered using lumenless leads (LLL). However, recent studies have also reported the use of style-driven leads (SDL). This study is the first systematic review comparing the outcomes of LBBAP with SDL vs. LLL.

METHODS

The review and meta-analysis included all available comparative studies published on Embase, PubMed, Web of Science, CENTRAL, and Scopus up to 6th March 2024.

RESULTS

Eight observational studies were included in the review. Meta-analysis showed that success rates of LBBAP performed with LLL and SDL were comparable (OR: 1.72 95% CI: 0.94, 3.17 I2 = 38%). Duration of implantation and total procedural duration were significantly lower in LBBAP performed with SDL. The pacing threshold was significantly higher, while pacing impedance was significantly lower in the SDL compared to the LLL group. Pacing QRS interval, R-wave amplitude, and stimulus to peak left ventricular activation time were similar in the two groups. Intra-operative and post-operative dislodgement were significantly higher in the SDL group, but no difference was noted in intra-operative perforation and pneumothorax risk.

CONCLUSION

Limited evidence from observational studies with inherent selection bias shows that success rates for LBBAP may not differ between SDL and LLL. While implantation of SDL may be significantly faster, it carries a higher risk of lead dislodgement. Both SDL and LLL are associated with comparable pacing characteristics except for reduced pacing impedance with SDL.

Stylet-driven Leads or Lumenless Leads for Conduction System Pacing

Stylet-driven leads have been recently introduced for conduction system pacing, while most of the previous experience has been obtained with lumenless leads. Design and structural characteristics of both lead types are significantly different, resulting in different implant techniques and independent learning curves. Lead performance appears to be comparable, whereas data on direct comparison of clinical outcomes are scarce. Currently, there are no specific clinical scenarios favouring the use of one lead type over another and the decision should rely on the individual experience of the implanter.

Alternative pacing strategies for optimal cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) via biventricular pacing (BVP) improves morbidity, mortality, and quality of life, especially in subsets of patients with impaired cardiac function and wide QRS. However, the rate of unsuccessful or complicated left ventricular (LV) lead placement through coronary sinus is 5-7%, and the rate of "CRT non-response" is approximately 30%. These reasons have pushed physicians and engineers to collaborate to overcome the challenges of LV lead implantation. Thus, various alternatives to BVP have been proposed to improve CRT effectiveness. His bundle pacing (HBP) has been increasingly used by activating the His-Purkinje system but is constrained by challenging implantation, low success rates, high and often unstable thresholds, and low perception. Therefore, the concept of pacing a specialized conduction system distal to the His bundle to bypass the block region was proposed. Multiple clinical studies have demonstrated that left bundle branch area pacing (LBBAP) has comparable electrical resynchronization with HBP but is superior in terms of simpler operation, higher success rates, lower and stable capture thresholds, and higher perception. Despite their well-demonstrated effectiveness, the transvenous lead-related complications remain major limitations. Recently, leadless LV pacing has been developed and demonstrated effective for these challenging patient cohorts. This article focuses on the current state and latest progress in HBP, LBBAP, and leadless LV pacing as alternatives for failed or non-responsive conventional CRT as well as their limits and prospects.