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Frontiers in Cardiovascular Medicine 2021Cardiac pacing is an effective therapy for treating patients with bradycardia due to sinus node dysfunction or atrioventricular block. However, traditional right... (Review)
Review
Cardiac pacing is an effective therapy for treating patients with bradycardia due to sinus node dysfunction or atrioventricular block. However, traditional right ventricular apical pacing (RVAP) causes electric and mechanical dyssynchrony, which is associated with increased risk for atrial arrhythmias and heart failure. Therefore, there is a need to develop a physiological pacing approach that activates the normal cardiac conduction and provides synchronized contraction of ventricles. Although His bundle pacing (HBP) has been widely used as a physiological pacing modality, it is limited by challenging implantation technique, unsatisfactory success rate in patients with wide QRS wave, high pacing capture threshold, and early battery depletion. Recently, the left bundle branch pacing (LBBP), defined as the capture of left bundle branch (LBB) via transventricular septal approach, has emerged as a newly physiological pacing modality. Results from early clinical studies have demonstrated LBBP's feasibility and safety, with rare complications and high success rate. Overall, this approach has been found to provide physiological pacing that guarantees electrical synchrony of the left ventricle with low pacing threshold. This was previously specifically characterized by narrow paced QRS duration, large R waves, fast synchronized left ventricular activation, and correction of left bundle branch block. Therefore, LBBP may be a potential alternative pacing modality for both RVAP and cardiac resynchronization therapy with HBP or biventricular pacing (BVP). However, the technique's widespread adaptation needs further validation to ascertain its safety and efficacy in randomized clinical trials. In this review, we discuss the current knowledge of LBBP.
PubMed: 33834042
DOI: 10.3389/fcvm.2021.630399 -
European Heart Journal Oct 2022Permanent transseptal left bundle branch area pacing (LBBAP) is a promising new pacing method for both bradyarrhythmia and heart failure indications. However, data... (Observational Study)
Observational Study
AIMS
Permanent transseptal left bundle branch area pacing (LBBAP) is a promising new pacing method for both bradyarrhythmia and heart failure indications. However, data regarding safety, feasibility and capture type are limited to relatively small, usually single centre studies. In this large multicentre international collaboration, outcomes of LBBAP were evaluated.
METHODS AND RESULTS
This is a registry-based observational study that included patients in whom LBBAP device implantation was attempted at 14 European centres, for any indication. The study comprised 2533 patients (mean age 73.9 years, female 57.6%, heart failure 27.5%). LBBAP lead implantation success rate for bradyarrhythmia and heart failure indications was 92.4% and 82.2%, respectively. The learning curve was steepest for the initial 110 cases and plateaued after 250 cases. Independent predictors of LBBAP lead implantation failure were heart failure, broad baseline QRS and left ventricular end-diastolic diameter. The predominant LBBAP capture type was left bundle fascicular capture (69.5%), followed by left ventricular septal capture (21.5%) and proximal left bundle branch capture (9%). Capture threshold (0.77 V) and sensing (10.6 mV) were stable during mean follow-up of 6.4 months. The complication rate was 11.7%. Complications specific to the ventricular transseptal route of the pacing lead occurred in 209 patients (8.3%).
CONCLUSIONS
LBBAP is feasible as a primary pacing technique for both bradyarrhythmia and heart failure indications. Success rate in heart failure patients and safety need to be improved. For wider use of LBBAP, randomized trials are necessary to assess clinical outcomes.
Topics: Humans; Female; Aged; Bundle of His; Cardiac Pacing, Artificial; Bundle-Branch Block; Bradycardia; Electrocardiography; Heart Failure; Treatment Outcome
PubMed: 35979843
DOI: 10.1093/eurheartj/ehac445 -
Heart Rhythm Sep 2023Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that...
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.
Topics: Child; Humans; Bundle of His; Treatment Outcome; Cardiac Conduction System Disease; Cardiac Resynchronization Therapy; Heart Failure; Electrocardiography
PubMed: 37283271
DOI: 10.1016/j.hrthm.2023.03.1538 -
Europace : European Pacing,... Apr 2023Conduction system pacing (CSP) has emerged as a more physiological alternative to right ventricular pacing and is also being used in selected cases for cardiac...
EHRA clinical consensus statement on conduction system pacing implantation: endorsed by the Asia Pacific Heart Rhythm Society (APHRS), Canadian Heart Rhythm Society (CHRS), and Latin American Heart Rhythm Society (LAHRS).
Conduction system pacing (CSP) has emerged as a more physiological alternative to right ventricular pacing and is also being used in selected cases for cardiac resynchronization therapy. His bundle pacing was first introduced over two decades ago and its use has risen over the last five years with the advent of tools which have facilitated implantation. Left bundle branch area pacing is more recent but its adoption is growing fast due to a wider target area and excellent electrical parameters. Nevertheless, as with any intervention, proper technique is a prerequisite for safe and effective delivery of therapy. This document aims to standardize the procedure and to provide a framework for physicians who wish to start CSP implantation, or who wish to improve their technique.
Topics: Humans; Latin America; Canada; Heart Conduction System; Cardiac Conduction System Disease; Cardiac Resynchronization Therapy; Bundle of His
PubMed: 37061848
DOI: 10.1093/europace/euad043 -
Circulation Research Aug 2019The cardiac conduction system (CCS) consists of distinct components including the sinoatrial node, atrioventricular node, His bundle, bundle branches, and Purkinje...
RATIONALE
The cardiac conduction system (CCS) consists of distinct components including the sinoatrial node, atrioventricular node, His bundle, bundle branches, and Purkinje fibers. Despite an essential role for the CCS in heart development and function, the CCS has remained challenging to interrogate because of inherent obstacles including small cell numbers, large cell-type heterogeneity, complex anatomy, and difficulty in isolation. Single-cell RNA-sequencing allows for genome-wide analysis of gene expression at single-cell resolution.
OBJECTIVE
Assess the transcriptional landscape of the entire CCS at single-cell resolution by single-cell RNA-sequencing within the developing mouse heart.
METHODS AND RESULTS
Wild-type, embryonic day 16.5 mouse hearts (n=6 per zone) were harvested and 3 zones of microdissection were isolated, including: Zone I-sinoatrial node region; Zone II-atrioventricular node/His region; and Zone III-bundle branch/Purkinje fiber region. Tissue was digested into single-cell suspensions, cells isolated, mRNA reverse transcribed, and barcoded before high-throughput sequencing and bioinformatics analyses. Single-cell RNA-sequencing was performed on over 22 000 cells, and all major cell types of the murine heart were successfully captured including bona fide clusters of cells consistent with each major component of the CCS. Unsupervised weighted gene coexpression network analysis led to the discovery of a host of novel CCS genes, a subset of which were validated using fluorescent in situ hybridization as well as whole-mount immunolabeling with volume imaging (iDISCO+) in 3 dimensions on intact mouse hearts. Further, subcluster analysis unveiled isolation of distinct CCS cell subtypes, including the clinically relevant but poorly characterized transitional cells that bridge the CCS and surrounding myocardium.
CONCLUSIONS
Our study represents the first comprehensive assessment of the transcriptional profiles from the entire CCS at single-cell resolution and provides a characterization in the context of development and disease.
Topics: Animals; Heart Conduction System; Mice; RNA-Seq; Single-Cell Analysis; Transcriptome
PubMed: 31284824
DOI: 10.1161/CIRCRESAHA.118.314578 -
Journal of Arrhythmia Oct 2020Junctional ectopic tachycardia (JET) is a tachyarrhythmia arising from the atrioventricular node and His bundle area. Enhanced normal automaticity has been postulated as... (Review)
Review
Junctional ectopic tachycardia (JET) is a tachyarrhythmia arising from the atrioventricular node and His bundle area. Enhanced normal automaticity has been postulated as the mechanism of JET in the majority of patients. It is more common in children and can be seen as congenital or in postoperative settings. It is often a narrow complex tachycardia but can present as a wide complex tachycardia as a result of aberrant conduction. Its differentiation from other arrhythmias especially atrioventricular nodal reentrant tachycardia (AVNRT) can be challenging. Medical treatment of JET is difficult, and catheter ablation remains the mainstay of treatment in refractory cases with a high risk of atrioventricular block and recurrence.
PubMed: 33024461
DOI: 10.1002/joa3.12410 -
JACC. Clinical Electrophysiology Sep 2021This study sought to assess the predictive value of the proposed electrocardiogram and intracardiac electrogram characteristics for confirmation of left bundle branch...
OBJECTIVES
This study sought to assess the predictive value of the proposed electrocardiogram and intracardiac electrogram characteristics for confirmation of left bundle branch (LBB) capture.
BACKGROUND
Previously proposed criteria to distinguish left bundle branch pacing (LBBP) and left ventricular septum (LVS) pacing (LVSP) have not been fully validated.
METHODS
A His bundle pacing lead, an LBBP lead, and a multielectrode catheter at the LVS were placed. Direct LBB capture was defined as demonstration of retrograde His potential on the His bundle pacing lead and/or anterograde left conduction system potentials on the multielectrode catheter during LBBP. The routinely used parameters-His, LBB potential, time from stimulus to peak ventricular activation (Stim-LVAT), and paced QRS morphology during LVSP and LBBP at various depths and outputs were analyzed.
RESULTS
Thirty patients (21 non-left bundle branch block [LBBB], 9 LBBB) who demonstrated direct LBB capture using the defined criteria were included. The proportion of paced right bundle branch block was 100% during LBB capture in all patients compared to 23.4% in non-LBBB and 44.4% in LBBB during LVSP. LBB potential was recorded in all patients during intrinsic rhythm (non-LBBB group) or His corrective pacing in LBBB. Paced QRS duration was longer during selective LBBP compared to nonselective LBBP or LVSP only. All patients with characteristics of selective LBBP or abrupt decrease in Stim-LVAT of ≥10 ms demonstrated LBB capture.
CONCLUSIONS
Direct LBB capture can be confirmed by recording retrograde His potential and anterograde left conduction system potentials. Abrupt decrease in Stim-LVAT of ≥10 ms and demonstration of selective LBBP could be used as simple criteria to confirm LBB capture.
Topics: Bundle of His; Bundle-Branch Block; Cardiac Pacing, Artificial; Heart Rate; Humans; Ventricular Septum
PubMed: 33933414
DOI: 10.1016/j.jacep.2021.02.018