Clinical outcomes of left bundle branch pacing compared to right ventricular apical pacing in patients with atrioventricular block

Long-Term Follow-Up of Left Bundle Branch Area Pacing in Pacing-Dependent Patients and Normal Cardiac Function

INTRODUCTION

Left bundle branch area pacing (LBBAP) has emerged as a novel physiological pacing strategy. The purpose of this study was to evaluate the long-term effect of LBBAP in ventricular pacing-dependent patients and baseline normal cardiac function.

METHODS

This retrospective observational study included patients who underwent LBBAP or RVP for bradycardia indications between January 2018 and July 2021. Baseline characteristics and electrophysiological, pacing and echocardiographic data were collected.

RESULTS

Sixty patients with VP% ≥ 40% were enrolled, including 30 patients in the LBBAP group and 30 patients in the RVP group. The mean follow-up time was 53.03 ± 8.10 months in the LBBAP group and 51.87 ± 11.68 months in the RVP group. No ventricular septum perforation was observed during the procedure or follow-up. The R-wave amplitudes did not differ between the two groups at implantation, but the R-wave amplitude in the LBBAP group at last follow-up was higher than that in the RVP group (17.67 ± 7.50 mV vs. 12.38 ± 5.36 mV, p = 0.003). Paced QRS duration in the LBBAP group was significantly shorter than that in the RVP group (138.93 ± 15.36 ms vs. 164.30 ± 19.48 ms, p < 0.0001). The LBBAP group had a higher LVEF (64.81 ± 5.49 vs. 60.44 ± 9.28, p = 0.041) and lower LVESD (29.70 ± 4.59 mm vs. 32.03 ± 3.97 mm, p = 0.039) than the RVP group at last follow-up.

CONCLUSION

This study found LBBAP electrodes had a stable anatomic position, better pacing parameters, and better maintaining cardiac performances than RVP in patients with normal cardiac function and bradyarrhythmia indications.

Left Bundle Branch Area Pacing Versus Right Ventricular Pacing in Patients With Atrioventricular Block: A Systematic Review and Meta-Analysis

BACKGROUND

Left bundle branch area pacing (LBBAP) is a new technique for patients with atrioventricular block (AVB) and preserved left ventricular ejection fraction (LVEF), potentially offering better cardiac function than right ventricular pacing (RVP).

METHODS

We searched databases and registries for studies that compared LBBAP with RVP in patients with AVB and preserved LVEF. We extracted data on various outcomes and pooled the effect estimates using random-effects models.

RESULTS

Our meta-analysis included 14 studies (10 observational and 4 RCTs) involving 3062 patients with AVB. The analysis revealed that the QRS duration was significantly shorter in the LBBAP group compared to the RVP group [MD = -35.56 ms; 95% CI: (-39.27, -31.85), p < 0.00001]. Patients in the LBBAP group also exhibited a significant increase in left ventricular ejection fraction (LVEF) [MD = 5.48%; 95% CI: (4.07%, 6.89%), p < 0.00001], and a significant reduction in left ventricular end-diastolic diameter (LVEDD) compared to RVP [MD = -3.98 mm; 95% CI: (-5.88, -2.09 mm), p < 0.0001]. In terms of clinical outcomes, LBBAP was associated with a significantly lower risk of heart failure hospitalizations (HFHs) compared to RVP [OR = 0.26; 95% CI: (0.16, 0.44), p < 0.0001]. However, no significant differences were observed between the two groups in the implant success rate, pacing impedance, or pacing threshold. The RVP group demonstrated a significantly higher R-wave amplitude increase than the LBBAP group [MD = 0.85 mV; 95% CI: (0.23, 1.46), p = .007]. Lastly, there was no significant difference in the incidence of complications between the two groups [OR = 2.12; 95% CI: (0.29, 15.52), p = 0.46].

CONCLUSION

LBBAP outperforms RVP in several cardiac function indicators, suggesting it may be a superior pacing method for AVB patients with preserved LVEF. However, the small sample size in studies and the result in heterogeneity call for more research to validate these findings and assess LBBAP's long-term effects.

Left Bundle Branch Area Pacing Compared to Right Ventricular Outflow Tract Septal Pacing: Mid-term Results and Learning Curve

Our study evaluated the efficacy and feasibility of left bundle branch area pacing (LBBAP) compared to right ventricular outflow tract septal pacing (RVOSP). We conducted a prospective, single-center, observational study involving 200 consecutive patients who required pacemaker implantation. The patients were divided into two groups (LBBAP and RVOSP), with 100 patients in each group. We aimed to compare the safety and efficacy, as well as the procedure and fluoroscopy times, between the two groups. Additionally, we aimed to describe the learning curve for the LBBAP group. The success and acute complication rates were similar (P = .56 vs. P = .65). The procedure time was longer in the LBBAP group compared to the RVOSP group (18 [13-28] vs. 11 [7-17] min; P < .001), while the fluoroscopy time was shorter in the LBBAP group compared to the RVOSP group (2.8 [1.3-3.7] vs. 3.1 [2-5.9] min; P = .02). The paced QRS interval was narrower in the LBBAP group (123.77 ± 10.25 vs. 159.79 ± 17.0 ms; P = .001). There were no significant differences in pacing parameters like R-wave sensing (9.6 ± 5.2 vs. 9.1 ± 4.7 mV; P = .91), bipolar impedance (685.9 ± 151.8 vs. 686.5 ± 158.6 Ω; P = .98), or pacing threshold (0.70 ± 0.29 vs. 0.64 ± 0.26 V @ 0.4 ms; P = .63). In the LBBAP group, both the procedure time (12 [10.5-15] vs. 32 [28.5-38.5] min; P < .001) and the fluoroscopy time (2 [1-4.6] vs. 5.1 [3.4-12] min; P < .01) were shorter in the last quartile (Q4) compared to the first quartile (Q1). The procedure time was similar between LBBAP Q4 and RVOSP (12 [10.5-15] vs. 11 [7-17] min; P = .33). LBBAP is as safe as RVOSP and achieves a narrower paced QRS compared to RVOSP. After a rapid learning curve, a shorter fluoroscopy time and a similar procedure time can be achieved.

Left bundle branch area pacing using a stylet-driven, retractable-helix lead: Short-term results from a prospective multicenter IDE trial (the BIO-CONDUCT study)

BACKGROUND

Left bundle branch area pacing (LBBAP) has swiftly emerged as a safe and effective alternative to right ventricular pacing. Limited data exist on the use of retractable-helix, stylet-driven leads for LBBAP.

OBJECTIVE

The objective of this study was to prospectively evaluate the performance and safety of a stylet-driven pacing lead in a rigorously controlled multicenter trial to support US market application.

METHODS

A multicenter, prospective, nonrandomized trial enrolled patients with standard pacing indications. Implant procedure and lead data, including threshold, sensing, impedance, and capture type, were collected through 3 months. Primary end points were freedom from LBBAP lead-related serious complications through 3 months and LBBAP implant success according to prespecified criteria. A blinded clinical events committee adjudicated all potential end point complications.

RESULTS

A total of 186 patients were included from 14 US sites. LBBAP implants were successful in 95.7% (178 of 186; 95% confidence interval 91.7%-98.1%; P < .0001 for comparison to the performance goal of 88%). Through the 3-month follow-up visit, 3 patients (1.7%) experienced a serious LBBAP complication (all lead dislodgments), resulting in a LBBAP lead-related complication-free rate of 98.3%. A total of 13 patients (7.8%) experienced any system- or procedure-related complication. The mean threshold was 0.89 V at 0.4 ms, the sensing value was 10.8 mV, and impedance was 608 Ω.

CONCLUSION

The short-term results from this prospective trial demonstrate both high implant success and freedom from LBBAP lead-related complications using this stylet-driven retractable helix lead. This trial supports the safety, use, and effectiveness of stylet-driven leads for performing contemporary physiologic pacing.

2024 HRS expert consensus statement on arrhythmias in the athlete: Evaluation, treatment, and return to play

Youth and adult participation in sports continues to increase, and athletes may be diagnosed with potentially arrhythmogenic cardiac conditions. This international multidisciplinary document is intended to guide electrophysiologists, sports cardiologists, and associated health care team members in the diagnosis, treatment, and management of arrhythmic conditions in the athlete with the goal of facilitating return to sport and avoiding the harm caused by restriction. Expert, disease-specific risk assessment in the context of athlete symptoms and diagnoses is emphasized throughout the document. After appropriate risk assessment, management of arrhythmias geared toward return to play when possible is addressed. Other topics include shared decision-making and emergency action planning. The goal of this document is to provide evidence-based recommendations impacting all areas in the care of athletes with arrhythmic conditions. Areas in need of further study are also discussed.

Left bundle branch area pacing using a lumenless lead: A systematic literature review and meta-analysis

BACKGROUND

Although left bundle branch area pacing (LBBAP) has been shown to be a feasible option for delivering physiological pacing, data are largely limited to single-center reports. The aim of this analysis was to systematically assess the safety and efficacy of LBBAP with the Model 3830 lead among primarily bradycardia patients.

METHODS AND RESULTS

PubMed, Embase, Cochrane Library, and Google Scholar were searched for full-text articles on LBBAP using the SelectSecure Model 3830 lumenless lead. Rates and means were estimated using random- and mixed-effects models. Of 3395 articles, 53 met inclusion criteria, representing 6061 patients undergoing an implant attempt. Average patient age was 68.1 years (95% CI: 66.6, 69.6) and 53.1% were male (95% CI: 50.5%, 55.7%). The average implant success rate among bradycardia-indicated patients was 92.7% (95% CI: 89.5%, 94.9%). The overall estimated procedural adverse event rate was 2.5% (95% CI: 1.1%, 5.4%). The estimated septal perforation rate at implant was 1.6% (95% CI: 1.0%, 2.6%) with no adverse clinical sequelae reported. Pacing thresholds were low at implant (0.67 V [95% CI: 0.64, 0.70]) and remained stable through 12 months (0.76 V [95% CI: 0.72, 0.80]). Among bradycardia-indicated patients, LVEF remained stable from baseline to post-implant (59.5% [95% CI: 57.9%, 61.1%] vs. 60.1% [95% CI: 58.5%, 61.7%]).

CONCLUSION

This meta-analysis including 6061 patients implanted with a Model 3830 lead for LBBAP found an average implant success rate of 92.7% and a procedural adverse event rate of 2.5% with stable electrical parameters and LVEF post-implant.

Conduction System Pacing: Hope, Challenges, and the Journey Forward

PURPOSE OF THE REVIEW

Cardiac pacing has evolved in recent years currently culminating in the specific stimulation of the cardiac conduction system (conduction system pacing, CSP). This review aims to provide a comprehensive overview of the available literature on CSP, focusing on a critical classification of studies comparing CSP with standard treatment in the two fields of pacing for bradycardia and cardiac resynchronization therapy in patients with heart failure. The article will also elaborate specific benefits and limitations associated with CSP modalities of His bundle pacing (HBP) and left bundle branch area pacing (LBBAP).

RECENT FINDINGS

Based on a growing number of observational studies for different indications of pacing therapy, both CSP modalities investigated are advantageous over standard treatment in terms of narrowing the paced QRS complex and preserving or improving left ventricular systolic function. Less consistent evidence exists with regard to the improvement of heart failure-related rehospitalization rates or mortality, and effect sizes vary between HBP and LBBAP. LBBAP is superior over HBP in terms of lead measurements and procedural duration. With regard to all reported outcomes, evidence from large scale randomized controlled clinical trials (RCT) is still scarce. CSP has the potential to sustainably improve patient care in cardiac pacing therapy if patients are appropriately selected and limitations are considered. With this review, we offer not only a summary of existing data, but also an outlook on probable future developments in the field, as well as a detailed summary of upcoming RCTs that provide insights into how the journey of CSP continues.

Prognostic benefits of His-Purkinje capture in physiological pacemakers for bradycardia

INTRODUCTION

Clinical outcomes of long-term ventricular septal pacing (VSP) without His-Purkinje capture remain unknown. This study evaluated the differences in clinical outcomes between conduction system pacing (CSP), VSP, and right ventricular pacing (RVP).

METHODS

Consecutive patients with bradycardia indicated for pacing from 2016 to 2022 were prospectively followed for the clinical endpoints of heart failure (HF)-hospitalizations and all-cause mortality at 2 years. VSP was defined as septal pacing due to unsuccessful CSP implant or successful CSP followed by loss of His-Purkinje capture within 90 days.

RESULTS

Among 1016 patients (age 73.9 ± 11.2 years, 47% female, 48% atrioventricular block), 612 received RVP, 335 received CSP and 69 received VSP. Paced QRS duration was similar between VSP and RVP, but both significantly longer than CSP (p < .05). HF-hospitalizations occurred in 130 (13%) patients (CSP 7% vs. RVP 16% vs. VSP 13%, p = .001), and all-cause mortality in 143 (14%) patients (CSP 7% vs. RVP 19% vs. VSP 9%, p < .001). The association of pacing modality with clinical events was limited to those with ventricular pacing (Vp) > 20% (pinteraction < .05). Adjusting for clinical risk factors among patients with Vp > 20%, VSP (adjusted hazard ratio [AHR]: 4.74, 95% confidence interval [CI]: 1.57-14.36) and RVP (AHR: 3.08, 95% CI: 1.44-6.60) were associated with increased hazard of HF-hospitalizations, and RVP (2.52, 95% CI: 1.19-5.35) with increased mortality, compared to CSP. Clinical endpoints did not differ between VSP and RVP with Vp > 20%, or amongst groups with Vp < 20%.

CONCLUSION

Conduction system capture is associated with improved clinical outcomes. CSP should be preferred over VSP or RVP during pacing for bradycardia.

Left bundle branch pacing better preserves ventricular mechanical synchrony than right ventricular pacing: a two-centre study

AIMS

Left bundle branch pacing (LBBP) has been shown to better maintain electrical synchrony compared with right ventricular pacing (RVP), but little is known about its impact on mechanical synchrony. This study investigates whether LBBP better preserves left ventricular (LV) mechanical synchronicity and function compared with RVP.

METHODS AND RESULTS

Sixty patients with pacing indication for bradycardia were included: LBBP (n = 31) and RVP (n = 29). Echocardiography was performed before and shortly after pacemaker implantation and at 1-year follow-up. The lateral wall-septal wall (LW-SW) work difference was used as a measure of mechanical dyssynchrony. Septal flash, apical rocking, and septal strain patterns were also assessed. At baseline, LW-SW work difference was small and similar in two groups. SW was markedly decreased, while LW work remained mostly unchanged in RVP, resulting in a larger LW-SW work difference compared with LBBP (1253 ± 687 mmHg·% vs. 439 ± 408 mmHg·%, P < 0.01) at last follow-up. In addition, RVP more often induced septal flash or apical rocking and resulted in more advanced strain patterns compared with LBBP. At 1 year follow-up, LV ejection fraction (EF) and global longitudinal strain (GLS) were more decreased in RVP compared with LBBP (ΔLVEF: -7.4 ± 7.0% vs. 0.3 ± 4.1%; ΔLVGLS: -4.8 ± 4.0% vs. -1.4 ± 2.5%, both P < 0.01). In addition, ΔLW-SW work difference was independently correlated with LV adverse remodelling (r = 0.42, P < 0.01) and LV dysfunction (ΔLVEF: r = -0.61, P < 0.01 and ΔLVGLS: r = -0.38, P = 0.02).

CONCLUSION

LBBP causes less LV mechanical dyssynchrony than RVP as it preserves a more physiologic electrical conduction. As a consequence, LBBP appears to preserve LV function better than RVP.

Left bundle branch area pacing improving the left atrial outcomes in pace-dependent patients compared with right ventricular outflow tract septal pacing

BACKGROUND

Recent studies suggested that the left bundle branch area pacing (LBBAP) has a better efficacy to reduce QRS duration and produce a lower pacing threshold than the conventional right ventricular outflow tract septal pacing (RVOP), which resulted in a better cardiac function and ventricular synchronization. However, whether the LBBAP has a better efficacy in improving left atrial structure, function in pace-dependent patients compared with RVOP has not been well studied.

OBJECTIVE

The purpose of this study was to compare the atrial outcomes of pace-dependent patients who received LBBAP or RVOP procedures.

METHODS AND RESULTS

A total of 72 patients (including II° AVB, high AVB, and III° AVB, excluding atrial fibrillation patients with atrioventricular block) consecutively enrolled in this single-center prospective clinical study and randomly assigned to the RVOP group and the LBBP group with 36 patients. All patients were pace-dependent. The changes in echocardiogram, speckle-tracking echocardiography, brain natriuretic peptide (BNP), and 6-min walking distance were documented and compared between two groups at baseline, 7 days, 1, 3, and 6 months after the implantation. There were no significant differences in baseline characteristics between the two groups. The results of the study were as following: (1) left atrial structure index: Our study indicated that there are no significant differences in left atrial anteroposterior dimension (LAAPD), left atrial superoinferior dimension, and left atrial mediolateral dimension between two groups. While the LAAPD in the LBBAP group was significantly reduced at 6 months after implantation ([38.22 ± 2.17] mm vs. [34.13 ± 1.59] mm, p < .05). (2) Left atrial strain index: We observed that the S% was significantly improved in both groups at 3 and 6 months after implantation but more prominent in the LBBAP group at 6 months (36.94 ± 11.67 vs. 25.87 ± 8.93, p = .01). SRs, SRe were improved in the RVOP group at 6 months after implantation but was further significantly increased in the LBBAP group. Similarly, the SRa in the LBBAP group was significantly better than the RVOP group after 6 months (-2.11 ± 0.75 vs. -2.51 ± 0.70, p = .04). (3) Left atrial ejection index: LAEF% in the LBBAP group was significantly improved compared with the RVOP group (60.02 ± 1.88 vs. 53.65 ± 2.45, p = .047) and baseline (60.02 ± 1.88 vs. 49.68 ± 2.75, p < .05) at 6 months after the surgery. (4) Left ventricular ejection index: The LVEF% in the LBBAP group was significantly increased than the RVOP group after 6 months (69.14 ± 4.99 vs. 64.60 ± 4.84, p = .01) and the BNP level was significantly lower in the LBBAP group compared with the RVOP group at 7 days, 1, 3, and 6 months after implantation (p < .05). (5) 6-min walking distance: the 6-min walking distance was significantly increased at 3 and 6 months after implantation compared with that before (p < .05) in both groups, but was more prominent in LBBAP groups ([483.03 ± 11.02] m vs. [431.09 ± 10.69] m,p < .05).

CONCLUSION

Compared with the traditional RVOP, the LBBAP procedure increased left atrial myocardial stress as well as left atrial ejection in pace-dependent patients at follow-up to 6 months.

Conduction system pacing: how far are we from the "electrical" bypass?

Conduction system pacing is an alternative practice to conventional right ventricular apical pacing. It is a method that maintains physiologic ventricular activation, based on a correct pathophysiological basis, in which the pacing lead bypasses the lesion of the electrical fibers and the electrical impulse transmits through the intact adjacent conduction system. For this reason, it might be reasonably characterized by the term "electrical bypass" compared to the coronary artery bypass in revascularization therapy. In this review, reference is made to the sequence of events in which conventional right ventricular pacing may cause adverse outcomes. Furthermore, there is a reference to alternative strategies and pacing sites. Interest focuses on the modalities for which there are data from the literature, namely for the right ventricular (RV) septal pacing, the His bundle pacing (HBP), and the left bundle branch pacing (LBBP). A more extensive reference is about the HBP, for which there are the most updated data. We analyze the considerations that limit HBP-wide application in three axes, and we also present the data for the implantation and follow-up of these patients. The indications with their most important studies to date are then described in detail, not only in their undoubtedly positive findings but also in their weak aspects, because of which this pacing mode has not yet received a strong recommendation for implementation. Finally, there is a report on LBBP, focusing mainly on its points of differentiation from HBP.

Clinical outcomes of left bundle branch area pacing: Prognosis and specific applications

Cardiac pacing has become a widely accepted treatment strategy for bradyarrhythmia and heart failure. However, conventional right ventricular pacing (RVP) has been associated with electrical dyssynchrony, which may result in atrial fibrillation and heart failure. To achieve physiological pacing, Deshmukh et al. reported the first case of His bundle pacing (HBP) in 2000. This strategy was reported to have preserved ventricular synchronization by activating the conventional conduction system. Nonetheless, due to the anatomical location of the His bundle (HB), several issues such as high pacing thresholds, lead fixation, and early battery depletion may pose a challenge. Recently, left bundle branch area pacing (LBBAP) has emerged as a novel physiological pacing strategy to achieve conduction system pacing by capturing the left bundle branch through the deep septum. Additionally, several studies have investigated the clinical outcomes of LBBAP. In this paper, we describe the pacing parameters, QRS duration (QRSd), cardiac function, complications, and specific applications of LBBAP in recent years.

Conduction system pacing and defibrillation support using a single-chamber defibrillator - A case report

We present a case of a 67-year-old male with heart failure with reduced ejection fraction due to a previous myocardial infarction, slow-conducting atrial fibrillation with an indication of pacemaker implantation, and sustained ventricular tachycardia, requiring defibrillation support in prevention of sudden cardiac death. Current guidelines recommend biventricular over conventional right ventricular pacing for patients with ejection fraction <40 % and atrioventricular conduction disorders in either sinus rhythm or atrial fibrillation, but in patients with a narrow baseline QRS complex, biventricular pacing still induces a form of electrical dyssynchrony. In our case we combined the advantages of conduction system pacing in form of left bundle branch area pacing, in order to prevent further left ventricular deterioration due to newly induced dyssyncrony, and also defibrillation support, using a single-chamber defibrillator with a DF-1/IS-1 connection.

Safety and efficacy of left bundle branch area pacing compared with right ventricular pacing in patients with bradyarrhythmia and conduction system disorders: Systematic review and meta-analysis

BACKGROUND

Right Ventricular Pacing (RVP) may have detrimental effects in ventricular function. Left Bundle Branch Area Pacing (LBBAP) is a new pacing strategy that appears to have better results. The aim of this systematic review and meta-analysis is to compare the safety and efficacy of LBBAP vs RVP in patients with bradyarrhythmia and conduction system disorders.

METHODS

MEDLINE, EMBASE and Pubmed databases were searched for studies comparing LBBAP with RVP. Outcomes were all-cause mortality, atrial fibrillation (AF) occurrence, heart failure hospitalizations (HFH) and complications. QRS duration, mechanical synchrony and LVEF changes were also assessed. Pairwise meta-analysis was conducted using random and fixed effects models.

RESULTS

Twenty-five trials with 4250 patients (2127 LBBAP) were included in the analysis. LBBAP was associated with lower risk for HFH (RR:0.33, CI 95%:0.21 to 0.50; p < 0.001), all-cause mortality (RR:0.52 CI 95%:0.34 to 0.80; p = 0.003), and AF occurrence (RR:0.43 CI 95%:0.27 to 0.68; p < 0.001) than RVP. Lead related complications were not different between the two groups (p = 0.780). QRSd was shorter in the LBBAP group at follow-up (WMD: -32.20 msec, CI 95%: -40.70 to -23.71; p < 0.001) and LBBAP achieved better intraventricular mechanical synchrony than RVP (SMD: -1.77, CI 95%: -2.45 to -1.09; p < 0.001). LBBAP had similar pacing thresholds (p = 0.860) and higher R wave amplitudes (p = 0.009) than RVP.

CONCLUSIONS

LBBAP has better clinical outcomes, preserves ventricular electrical and mechanical synchrony and has excellent pacing parameters, with no difference in complications compared to RVP.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Risk of Atrial Fibrillation Following Left Bundle Branch Area Pacing versus Right Ventricular Pacing and Biventricular Pacing: A Systematic Review and Meta-Analysis

Background

Left bundle branch pacing (LBBP) is a relatively novel physiological pacing strategy with better electrocardiogram characteristics and pacing parameters than other pacing strategies. At present, no meta-analysis or systematic review has examined the risk of atrial fibrillation (AF) after LBBP compared to other pacing strategies.

Methods

We searched the PubMed, Embase, and Cochrane Library databases from inception through September 18, 2022 to identify relevant studies reporting AF incidence rates after LBBP. The incidence of AF following LBBP and that associated with other pacing strategies were extracted and summarized for the meta-analysis. We used odds ratios (ORs) and 95% confidence intervals (CIs) as summary estimates.

Results

Five studies with 1144 participants were included. The pooled rate of AF was 3.7% (95% CI, 0.8%-8.0%) in the LBBP group and 15.5% (95% CI: 9.6%-22.4%) in the other pacing strategies (right ventricular pacing [RVP] and biventricular pacing [BVP]). Compared with other pacing strategies, LBBP was associated with a lower AF risk (OR, 0.33; 95% CI: 0.22-0.51, I 2 = 0.0%; p = 0.485). Similar results were observed for LBBP when compared with RVP (OR: 0.33, 95% CI: 0.22-0.51, I 2 = 0.0%, p = 0.641) and BVP (OR: 0.47, 95% CI: 0.01-15.22, I 2 = 60.4%, p = 0.112).

Conclusions

Compared with BVP and RVP, LBBP was associated with a significantly lower risk of AF. However, further large-sample randomized controlled trials are needed to confirm that LBBP is superior to other pacing strategies in reducing AF risk.

Comparison of Depolarization and Repolarization Parameters in Left vs. Right Ventricular Septal Pacing—An Intraprocedural Electrocardiographic Study

Compared with conventional right ventricular septal pacing (RVSP), several studies have shown a net clinical benefit of left bundle branch area pacing (LBBAP) in terms of ejection fraction preservation and reduced hospitalizations for heart failure. The purpose of this study was to compare acute depolarization and repolarization electrocardiographic parameters between LBBAP and RVSP in the same patients during the LBBAP implant procedure. We prospectively included 74 consecutive patients subjected to LBBAP from 1 January to 31 December 2021 at our institution in the study. After the lead was placed deep into the ventricular septum, unipolar pacing was performed and 12-lead ECGs were recorded from the distal (LBBAP) and proximal (RVSP) electrodes. QRS duration (QRSd), left ventricular activation time (LVAT), right ventricular activation time (RVAT), QT and JT intervals, QT dispersion (QTd), T-wave peak-to-end interval (Tpe), and Tpe/QT were measured for both instances. The final LBBAP threshold was a 0.7 ± 0.31 V at 0.4 ms duration with a sensing threshold of 10.7 ± 4.1 mV. RVSP produced a significantly larger QRS complex than the baseline QRS (194.88 ± 17.29 ms vs. 141.89 ± 35.41 ms, p < 0.001), while LBBAP did not significantly change the mean QRSd (148.10 ± 11.52 ms vs. 141.89 ± 35.41 ms, p = 0.135). LVAT (67.63 ± 8.79 ms vs. 95.89 ± 12.02 ms, p < 0.001) and RVAT (80.54 ± 10.94 ms vs. 98.99 ± 13.80 ms, p < 0.001) were significantly shorter with LBBAP than with RVSP. Moreover, all the repolarization parameters studied were significantly shorter in LBBAP than in RVSP (QT—425.95 ± 47.54 vs. 487.30 ± 52.32; JT—281.85 ± 53.66 vs. 297.69 ± 59.02; QTd—41.62 ± 20.07 vs. 58.38 ± 24.44; Tpe—67.03 ± 11.19 vs. 80.27 ± 10.72; and Tpe/QT—0.158 ± 0.028 vs. 0.165 ± 0.021, p < 0.05 for all), irrespective of the baseline QRS morphology. LBBAP was associated with significantly better acute depolarization and repolarization electrocardiographic parameters compared with RVSP.

Clinical Outcomes in Conduction System Pacing Compared to Right Ventricular Pacing in Bradycardia

BACKGROUND

Conduction system pacing (CSP) provides more physiological ventricular activation than right ventricular pacing (RVP).

OBJECTIVES

This study evaluated the differences in clinical outcomes in patients receiving CSP and RVP.

METHODS

Consecutive patients with pacemakers implanted for bradycardia from 2016 to 2021 in 2 centers were prospectively followed for the primary composite outcome of heart failure (HF) hospitalizations, upgrade to biventricular pacing, or all-cause mortality, stratified by ventricular pacing burden (Vp) .

RESULTS

Among 860 patients (mean age 74 ± 11 years, 48% female, 48% atrioventricular block), 628 received RVP and 231 received CSP (95 His-bundle pacing, 136 left bundle branch pacing). The primary outcome occurred in 217 (25%) patients, more commonly in patients with RVP than CSP (30% vs 13%, P < 0.001). In multivariable analyses, CSP was independently associated with 47% reduction of the primary outcome (adjusted hazard ratio [AHR]: 0.53; 95% CI: 0.29-0.97; P = 0.04) and HF hospitalization alone (AHR: 0.40; 95% CI: 0.17-0.95; P = 0.04), among only patients with Vp >20%. The incidence of the primary outcome was highest among RVP with Vp >20% and lowest in CSP with Vp >20% (35% vs 10%, P < 0.001). Compared with RVP with Vp >20%, both CSP with Vp >20% (AHR: 0.51; 95% CI: 0.28-0.91; P = 0.02) and all patients with Vp ≤20% (AHR: 0.73; 95% CI: 0.54-0.99; P = 0.04) were independently associated with reduced primary outcome, driven primarily by reductions in HF hospitalizations (P < 0.05). Event-free survival was similar between CSP with Vp >20% and those needing ≤20% Vp.

CONCLUSIONS

CSP significantly reduced adverse clinical outcomes for bradycardic patients requiring ventricular pacing and should be the preferred pacing modality of choice.

A systematic review and Bayesian network meta-analysis comparing left bundle branch pacing, his bundle branch pacing, and right ventricular pacing for atrioventricular block

Background

Although right ventricular pacing (RVP) is recommended by most of the guidelines for atrioventricular block, it can cause electrical and mechanical desynchrony, impair left ventricular function, and increase the risk of atrial fibrillation. Recently, the His-Purkinje system pacing, including His bundle pacing (HBP) and left bundle branch pacing (LBBP), has emerged as a physiological pacing modality. However, few studies have compared their efficacy and safety in atrioventricular block (AVB).

Methods and results

The PubMed, Web of Science, Cochrane Library, and ScienceDirect databases were searched for observational studies and randomized trials of patients with atrioventricular block requiring permanent pacing, from database inception until 10 January 2022. The primary outcomes were complications and heart failure hospitalization. The secondary outcomes included changes in left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDD), pacing parameters, procedure duration, and success rate. After extracting the data at baseline and the longest follow-up duration available, a pairwise meta-analysis and a Bayesian random-effects network meta-analysis were performed. Odds ratios (ORs) with 95% confidence intervals (CIs) or 95% credible intervals (CrIs) were calculated for dichotomous outcomes, whereas mean differences (MDs) with 95% CIs or 95% CrIs were calculated for continuous outcomes. Seven studies and 1,069 patients were included. Overall, 43.4% underwent LBBP, 33.5% HBP, and 23.1% RVP. Compared with RVP, LBBP and HBP were associated with a shorter paced QRS duration and a more preserved LVEF. HBP significantly increased the pacing threshold and reduced the R-wave amplitude. There was no difference in the risk of complications or the implant success rate. The pacing threshold remained stable during follow-up for the three pacing modalities. The pacing impedance was significantly reduced in HBP, while a numerical but non-significant pacing impedance decrease was observed in both LBBP and RVP. LBBP was associated with an increased R-wave amplitude during follow-up.

Conclusion

In this systematic review and network meta-analysis, HBP and LBBP were superior to RVP in paced QRS duration and preservation of LVEF for patients with atrioventricular block. LBBP was associated with a lower pacing threshold and a greater R-wave amplitude than HBP. However, the stability of the pacing output of LBBP may be a concern. Further investigation of the long-term efficacy in left ventricular function and the risk of heart failure hospitalization is needed.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=315046], identifier [CRD42022315046].

Left bundle branch pacing in a ventricular pacing dependent patient with heart failure: A case report

BACKGROUND

Left bundle branch pacing (LBBP) is a physiological pacing method that has emerged in recent years. It is an ideal choice for patients with complete left bundle branch block who are in need of cardiac resynchronization therapy (CRT). Moreover, LBBP is superior in maintaining physiological ventricular activation and can effectively improve heart function and quality of life in patients with pacemaker-induced cardiomyopathy. However, LBBP in pacing-dependent patients who already have cardiac dysfunction has not been well assessed.

CASE SUMMARY

A 69-year-old male patient presented with symptoms of chest tightness, palpitation and systolic heart failure with New York Heart Association class III for 1 mo. The 12-lead electrocardiogram showed atrial fibrillation with third-degree atrioventricular block and ventricular premature beat. Holter revealed a right bundle branch block, atrial fibrillation with third-degree atrioventricular block, frequent multifocal ventricular premature beats, Ron-T and ventricular tachycardia. The echocardiogram documented an enlarged left atrium and left ventricle and a low left ventricular ejection fraction. Coronary angiography indicated a stenosis of 30% in the middle left anterior descending artery. Apparently, a CRT-D pacemaker was the best choice for this patient according to previous findings. However, the patient was worried about the financial burden. A single-chamber pacemaker with LBBP was selected, with the plan to take amiodarone and upgrade with dual-chamber implantable cardioverter-defibrillator or CRT-D at an appropriate time. During the follow-up at 3 mo after LBBP, the patient showed an improvement in cardiac function with slight improvement in echocardiography parameters, and the New York Heart Association functional class was maintained at I. Moreover, the patient no longer suffered from chest tightness and palpitation. Holter showed decreased ventricular arrhythmia of less than 5%.

CONCLUSION

LBBP might be used in patients with heart failure and a high-degree atrioventricular block as an alternative to conventional CRT.

Assessing cardiac mechanical dyssynchrony in left bundle branch area pacing and right ventricular septal pacing using myocardial perfusion scintigraphy in the acute phase of pacemaker implantation

INTRODUCTION

Left bundle branch area pacing (LBBAP) has recently been reported to be a new, clinically feasible and safe physiological pacing strategy. The present study aims to investigate the usefulness of LBBAP in reducing mechanical dyssynchrony compared with right ventricular septal pacing (RVSP).

METHODS AND RESULTS

A total of 39 LBBAP patients, 42 RVSP patients, and 93 healthy control participants were retrospectively evaluated. We compared phase analysis- (bandwidth, phase standard deviation [PSD], entropy) and regional wall motion analysis parameters. Wall motion analysis parameters included the time to the end-systolic frame (TES) assessed using single-photon emission computed tomography analysis. The maximum differences between segmental TES (MDTES), the standard deviation of TES (SDTES), and the TES difference between the lateral and septal segments (DTES-LS) were obtained. All phase analysis parameters were significantly smaller in the LBBAP group than in the RVSP group (bandwidth: LBBAP, 74 ± 31° vs. RVSP, 102 ± 59°, p=0.009; PSD: LBBAP, 19 ± 6.7° vs. RVSP, 26 ± 15°, p=0.007; entropy: LBBAP, 0.57 ± 0.07 vs. RVSP, 0.62 ± 0.11 p=0.009). The regional wall motion analysis parameters were also smaller in the LBBAP group than in the RVSP group (MDTES:LBBAP, 17 ± 7.1% vs. RVSP, 25 ± 14%, p=0.004; SDTES :LBBAP, 4.5 ± 1.7% vs. RVSP, 6.0 ± 3.5%, p=0.015; DTES-LS: LBBAP, 4.1 ± 3.4% vs. RVSP, 7.1 ± 5.4%, p=0.004). All phase analysis and wall motion analysis parameters were same in the LBBAP and control groups.

CONCLUSION

LBBAP may reduce mechanical dyssynchrony and achieve greater physiological ventricular activation than RVSP. This article is protected by copyright. All rights reserved.

Clinical Outcomes of Left Bundle Branch Area Pacing in Comparison with Right Ventricular Septal Pacing in Patients with High Ventricular Pacing Ratio ≥40%

Background

Methods

Results

Conclusion

Evaluation of clinical safety and efficacy of left bundle branch area pacing in comparison with right ventricular septal pacing

ABSTRACT

Left bundle branch area pacing (LBBaP) has recently emerged as a new physiological pacing strategy. The purpose of this study is to compare LBBaP with right ventricular sepal pacing (RVSP) in terms of their clinical safety and efficacy.From February 2019 to May 2020, consecutive pacing-indicated patients were prospectively enrolled and divided into 2 groups. Ventricular synchrony indexes such as QRS duration (QRSd), interventricular mechanical delay and septal-posterior wall motion delay, left ventricular function such as left ventricular end-diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF), pacing parameters, and complications were evaluated in the perioperative period and during follow-up.LBBaP was successful in 45 patients (88.2%), and finally 46 patients underwent RVSP. With LBBaP, ventricular electricalmechanical synchrony were similar to those of native-conduction system (P = .78). However, the ventricular electrical synchrony (QRSd, 108.47±7.64 vs 130.63±13.63ms, P < .001) and mechanical synchrony (interventricular mechanical delay, 27.68±4.33 vs 39.88±5.83, P < .001; septal-posterior wall motion delay, 40.39±23.21 vs 96.36±11.55, P < .001) in the LBBaP group were significantly better than those in the RVSP group. No significant differences in LVEDD (46 [44-48.5] vs 47 [44-52] mm, P = .49) and LVEF% (66 [62.5-70] vs 64 [61-68], P = .76) was observed between 2 groups at last follow-up. But, in the subgroup analysis, LVEDD was shorter (46 [44-49] vs 50 [47-58] mm, P = .03) and the LVEF% was higher (65 [62-68] vs 63 [58-65], P = .02) in the LBBaP-H (high ventricular pacing ratio >40%) group compared with RVSP-H group at last follow-up. There were lower capture thresholds (0.59±0.18V vs 0.71 ± 0.26 V, P = 0.01) at implantation in the LBBaP group than those in the RVSP group, with R-wave amplitudes and pacing impedances showing no significant difference between 2 groups. No serious complications were found in both 2 groups at implantation and follow-ups.This study confirms the clinical safety and efficacy of LBBaP, and it produces better ventricular electrical-mechanical synchrony than RVSP. The event of pacing-induced left ventricular dysfunction is lower in the LBBaP-H group than RVSP-H group.

His-Purkinje conduction system pacing: A systematic review and network meta-analysis in bradycardia and conduction disorders

BACKGROUND

His-Purkinje conduction system pacing (HPCSP) has emerged as an effective alternative to overcome the limitations of right ventricular pacing (RVP) via physiological left ventricular activation, but there remains a paucity of comparative information for His bundle pacing (HBP) and left bundle branch pacing (LBBP).

METHODS

A Bayesian random-effects network analysis was conducted to compare the relative effects of HBP, LBBP, and RVP in patients with bradycardia and conduction disorders. PubMed, Embase, Cochrane Library, and Web of Science were systematically searched from database inception until September 21, 2021.

RESULTS

Twenty-eight studies involving 4160 patients were included in this meta-analysis. LBBP significantly improved success rate, pacing threshold, pacing impedance, and R-wave amplitude compared with HBP. LBBP also demonstrated a nonsignificant trend towards superior outcomes of lead complications, heart failure hospitalization, atrial fibrillation, and all-cause death. However, HBP was associated with significantly shorter paced QRS duration relative to LBBP. Despite higher success rates, shorter procedure/fluoroscopy duration, and fewer lead complications, patients receiving RVP were more likely to experience reduced left ventricular ejection fraction, longer paced QRS duration, and higher rates of heart failure hospitalization than those receiving HPCSP. No statistical differences were observed in the remaining outcome measures.

CONCLUSIONS

This network meta-analysis demonstrates the efficacy and safety of HPCSP for the treatment of bradycardia and conduction disorders, with differences in pacing parameters, electrophysiology characteristics, and clinical outcomes between HBP and LBBP. Larger-scale, long-term comparative studies are warranted for further verification.

Clinical outcomes of left bundle branch pacing compared to right ventricular apical pacing in patients with atrioventricular block

Background

Left bundle branch pacing (LBBP) can produce near normalization of QRS duration. This has recently emerged as alternative technique to right ventricular pacing and His bundle pacing.

Hypothesis

The purpose of this study is to evaluate clinical outcomes of LBBP compared to right ventricular apical pacing (RVAP).

Methods

A total of 70 AVB patients with indications for ventricular pacing were retrospectively studied. LBBP was attempted in 33 patients, classified as LBBP group. The other patients were classified as RVAP group. Pacing parameters, electrocardiogram and echocardiogram characteristics, heart failure hospitalization (HFH), and atrial fibrillation (AF) were evaluated perioperatively and at follow‐ups. Patients were followed in the device clinic for a minimum of 12 months and up to 24 months at a 3–6 monthly interval.

Results

LBBP was successful in 29 of 33(87.9%) patients while all 37 of the remaining patients successfully underwent RVAP. Paced QRS duration was significantly narrower in the LBBP group compare to RVAP(110.75 ± 6.77 ms vs. 154.29 ± 6.96 ms, p = .000) at implantation, and the difference persisted during follow‐ups. Pacing thresholds (at implantation: 0.68 ± 0.22 V in the LBBP group and 0.73 ± 0.23 V in the RVAP group, p = .620) remained low and stable during follow‐ups. The cardiac function in the LBBP group remained stable during follow‐ups (LVEF%:55.08 ± 4.32 pre‐operation and 54.17 ± 4.34 at the end of follow‐up, p = .609), and better than RVAP group (LVEF%: 54.17 ± 4.34 vs. 50.14 ± 2.14, p = .005). Less HFH was observed in the LBBP group (2/29,6.89%) compared to RVAP group (10/37,27.03%).

Conclusions

The present investigation demonstrates the safety and feasibility of LBBP that produces narrower paced QRS duration than RVAP. LBBP is associated with reduction in the occurrence of pacing‐induced left ventricular dysfunction and HFH compared to RVAP in patients requiring permanent pacemakers.