The Physiologic Mechanisms of Paced QRS Narrowing During Left Bundle Branch Pacing in Right Bundle Branch Block Patients

A systematic review and meta-analysis of the impact of left bundle branch area pacing on right ventricular function

Objective

This study aims to systematically evaluate and perform a meta-analysis on the effects of LBBAP on right ventricular (RV) function by collecting data on Right Ventricular Fractional Area Change (RV-FAC), Tricuspid Annular Plane Systolic Excursion (TAPSE), Interventricular Mechanical Delay (IVMD), and the incidence of tricuspid regurgitation (TR) worsening in Left bundle branch area pacing (LBBAP) patients.

Methods

A comprehensive search was conducted for studies published from the establishment of the respective databases until October 2024 in PubMed, Embase, Web of Science, and the Cochrane Library. After screening and data extraction, the Newcastle-Ottawa Scale was used for the quality assessment of the included cohort studies, and meta-analysis was performed using R software. The effect size was estimated using either a random-effect model or a fixed-effect model, with odds ratio (OR) and mean difference (MD).

Results

A total of 14 studies were included, analyzing 1,555 LBBAP patients. The meta-analysis revealed that compared with intrinsic conduction, LBBAP implantation significantly improved RV-FAC (MD = 1.93; 95% CI: 0.64-3.23, P = 0.0034) and TAPSE (MD = 1.57; 95% CI: 1.07-2.06, P < 0.0001). Compared to the RVP group, LBBAP implantation significantly shortened IVMD (MD = -21.27; 95% CI: -31.33 to -11.22, P < 0.0001). For patients with RV dysfunction or right bundle branch block (RBBB), LBBAP implantation also significantly reduced IVMD (MD = -31.31; 95% CI: -37.10 to -25.52, P < 0.0001). The incidence of TR worsening within one year after LBBAP was approximately 8%, increasing to 23% beyond one year.

Conclusion

This meta-analysis demonstrates the superiority of LBBAP over intrinsic conduction in improving RV systolic function. Compared to RVP, LBBAP significantly enhances biventricular synchronization. Furthermore, LBBAP also improves ventricular synchronization in patients with RV dysfunction or RBBB.

Cardiac Resynchronisation with Conduction System Pacing

To date, biventricular pacing (BiVP) has been the standard pacing modality for cardiac resynchronisation therapy. However, it is non-physiological, with the activation spreading between the left ventricular epicardium and right ventricular endocardium. Up to one-third of patients with heart failure who are eligible for cardiac resynchronisation therapy do not derive benefit from BiVP. Conduction system pacing (CSP), which includes His bundle pacing and left bundle branch area pacing, has emerged as an alternative to BiVP for cardiac resynchronisation. There is mounting evidence supporting the benefits of CSP in achieving synchronous ventricular activation and repolarisation. The aim of this review is to summarise the current options and outcomes of CSP when used for cardiac resynchronisation in patients with heart failure.

Reverse of left ventricular remodeling in heart failure patients with left bundle branch area pacing: Systematic review and meta-analysis

BACKGROUND

Left bundle branch area pacing (LBBAP) has recently become a promising option for the near-natural restoration of electrical activation. However, the clinical relevance of therapeutic effects in individuals with heart failure with reduced ejection fraction (HFrEF) and dyssynchrony remains unknown.

METHODS

MEDLINE, EMBASE, and Cochrane databases were searched from inception until June 2022. Data from each study was combined using a random-effects model, the generic inverse variance method of DerSimonian and Laird, to calculate standard mean differences and pooled incidence ratio, with 95% confidence intervals (CIs).

RESULTS

A total of 772 HFrEF patients were analyzed from 15 observational studies per protocol. The success rate of LBBAP implantation was 94.8% (95% CI 89.9-99.6, I2 = 79.4%), which was strongly correlated with shortening QRS duration after LBBAP implantation, with a mean difference of -48.10 ms (95% CI -60.16 to -36.05, I2 = 96.7%). Over a period of 6-12 months of follow-up, pacing parameters were stable over time. There were significant improvements in left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic diameter (LVEDD), and left ventricular end-diastolic volume (LVEDV) with mean difference of 16.38% (95% CI 13.13-19.63, I2 = 90.2%), -46.23 ml (95% CI -63.17 to -29.29, I2 = 86.82%), -7.21 mm (95% CI -9.71 to -4.71, I2 = 84.6%), and -44.52 ml (95% CI -64.40 to -24.64, I2 = 85.9%), respectively.

CONCLUSIONS

LBBAP was associated with improvements in both cardiac function and electrical synchrony. The benefits of LBBAP in individuals with HFrEF and dyssynchrony should be further validated by randomized studies.

Economic evaluation in cardiac electrophysiology: Determining the value of emerging technologies

Cardiac electrophysiology is a constantly evolving speciality that has benefited from technological innovation and refinements over the past several decades. Despite the potential of these technologies to reshape patient care, their upfront costs pose a challenge to health policymakers who are responsible for the assessment of the novel technology in the context of increasingly limited resources. In this context, it is critical for new therapies or technologies to demonstrate that the measured improvement in patients' outcomes for the cost of achieving that improvement is within conventional benchmarks for acceptable health care value. The field of Health Economics, specifically economic evaluation methods, facilitates this assessment of value in health care. In this review, we provide an overview of the basic principles of economic evaluation and provide historical applications within the field of cardiac electrophysiology. Specifically, the cost-effectiveness of catheter ablation for both atrial fibrillation (AF) and ventricular tachycardia, novel oral anticoagulants for stroke prevention in AF, left atrial appendage occlusion devices, implantable cardioverter defibrillators, and cardiac resynchronization therapy will be reviewed.