His Bundle Pacing: A New Frontier in the Treatment of Heart Failure

Conduction System Pacing in Pediatrics and Congenital Heart Disease, a Single Center Series of 24 Patients

His-bundle pacing has demonstrated feasibility in numerous adult studies to reverse and prevent pacing-induced cardiomyopathy, however, is met with higher capture thresholds with deployment sheaths designed for adults with his-bundles in the typical location. To describe 24 pediatric and adult congenital patients post-physiologic pacing. Patients at the University of Minnesota Masonic Children's Hospital with congenital complete heart block or congenital heart disease and atrioventricular block presented for pacemaker placement between November 2019 and January 2021. Twenty-four patients had attempted his-bundle placement using either Medtronic's C315 or C308 sheaths and 3830 leads except for 3 patients who had Boston Scientific's His system with the Shape 3 sheath and 7842 leads. Twenty-four total patients underwent physiologic pacing (23 his-bundle, 13 female, 11 male) with median age of 14 years (range 8-39 years) with median weight of 51 kg (range 21.2-81 kg) with five right-sided implants performed. Twelve patients had congenital heart disease including atrioventricular canal defects, tetralogy of Fallot, and ventricular septal defect repairs (nine patients with ventricular septal defect repairs). Twelve patients had selective His-bundle pacing (six with congenital heart disease). Median threshold to capture was 0.5 V at 0.4 ms (range 0.4 to 1.1 V at 0.4 ms), impedance 570 ohms (range 456-1140 ohms), and sensing median of 9.7 mV (range 1.5-13.8 mV if present). The median follow-up time was 610 days (range 240-760 days). No complications occurred peri-procedurally or during follow-up. His-bundle pacing is feasible in pediatric and congenital heart disease patients.

Conduction System Stimulation to Avoid Left Ventricle Dysfunction

BACKGROUND

Right ventricular apical pacing (RVAP) can produce left ventricle dysfunction. Conduction system pacing (CSP) has been used successfully to reverse left ventricle dysfunction in patients with left bundle branch block. To date, data about CSP prevention of left ventricle dysfunction in patients with preserved left ventricular ejection fraction (LVEF) are scarce and limited mostly to nonrandomized studies. Our aim is to demonstrate that CSP can preserve normal ventricular function compared with RVAP in the setting of a high burden of ventricular pacing.

METHODS

Consecutive patients with a high-degree atrioventricular block and preserved or mildly deteriorated LVEF (>40%) were included in this prospective, randomized, parallel, controlled study, comparing conventional RVAP versus CSP.

RESULTS

Seventy-five patients were randomized, with no differences between basal characteristics in both groups. The stimulated QRS duration was significantly longer in the RVAP group compared with the CSP group (160.4±18.1 versus 124.2±20.2 ms; p<0.01). Seventy patients were included in the intention-to-treat analyses. LVEF showed a significant decrease in the RVAP group at 6 months compared with the CSP group (mean difference, -5.8% [95% CI, -9.6% to -2%]; P<0.01). Left ventricular end-diastolic diameter showed an increase in the RVAP group compared with the CSP group (mean difference, 3.2 [95% CI, 0.1-6.2] mm; P=0.04). Heart failure-related admissions were higher in the RVAP group (22.6% versus 5.1%; P=0.03).

CONCLUSIONS

Conduction system stimulation prevents LVEF deterioration and heart failure-related admissions in patients with normal or mildly deteriorated LVEF requiring a high burden of ventricular pacing. These results are only short term and need to be confirmed by further larger studies.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT06026683.

Injectable hydrogel electrodes as conduction highways to restore native pacing

There is an urgent clinical need for a treatment regimen that addresses the underlying pathophysiology of ventricular arrhythmias, the leading cause of sudden cardiac death. The current report describes the design of an injectable hydrogel electrode and successful deployment in a pig model with access far more refined than any current pacing modalities allow. In addition to successful cardiac capture and pacing, analysis of surface ECG tracings and three-dimensional electroanatomic mapping revealed a QRS morphology comparable to native sinus rhythm, strongly suggesting the hydrogel electrode captures the deep septal bundle branches and Purkinje fibers. In an ablation model, electroanatomic mapping data demonstrated that the activation wavefront from the hydrogel reaches the mid-myocardium and endocardium much earlier than current single-point pacing modalities. Such uniform activation of broad swaths of tissue enables an opportunity to minimize the delayed myocardial conduction of heterogeneous tissue that underpins re-entry. Collectively, these studies demonstrate the feasibility of a new pacing modality that most closely resembles native conduction with the potential to eliminate lethal re-entrant arrhythmias and provide painless defibrillation.

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.

[Follow-up of the patient with pacemakers: Interrogation and basic programming]

Permanent pacemakers are a frequently used therapeutic modality. Its use has had a great impact on the morbidity and mortality and quality of life of patients with heart rhythm disturbances, with an exponential increase observed in recent decades. The use of this strategy presents different phases, in which follow-up throughout the useful life of the device is a fundamental and determinant pillar of the efficacy and safety of this therapeutic modality. This review seeks to provide a clear and structured update of the fundamental aspects to consider in the follow-up of all patients with pacemakers. The follow-up of the patient with a pacemaker must follow a complete, systematic and periodic protocol, evaluating aspects and parameters related to the patient and the pacemaker, in order to ensure the proper and safe operation of the device adapted to the person.

Transcatheter Aortic Valve Implantation and Cardiac Conduction Abnormalities: Prevalence, Risk Factors and Management

Over the last decades, transcatheter aortic valve implantation (TAVI) or replacement (TAVR) has become a potential, widely accepted, and effective method of treating aortic stenosis in patients at moderate and high surgical risk and those disqualified from surgery. The method evolved what translates into a noticeable decrease in the incidence of complications and more beneficial clinical outcomes. However, the incidence of conduction abnormalities related to TAVI, including left bundle branch block and complete or second-degree atrioventricular block (AVB), remains high. The occurrence of AVB requiring permanent pacemaker implantation is associated with a worse prognosis in this group of patients. The identification of risk factors for conduction disturbances requiring pacemaker placement and the assessment of their relation to pacing dependence may help to develop methods of optimal care, including preventive measures, for patients undergoing TAVI. This approach is crucial given the emerging evidence of no worse outcomes for intermediate and low-risk patients undergoing TAVI in comparison to surgical aortic valve replacement. This paper comprehensively discusses the mechanisms, risk factors, and consequences of conduction abnormalities and arrhythmias, including AVB, atrial fibrillation, and ventricular arrhythmias associated with aortic stenosis and TAVI, as well as provides insights into optimized patient care, along with the potential of conduction system pacing and cardiac resynchronization therapy, to minimize the risk of unfavorable clinical outcomes.

Prognostic Impact of the Increase in Cardiac Troponin Levels during Tafamidis Therapy in Patients with Transthyretin Cardiac Amyloidosis

BACKGROUND

Recent clinical trials have demonstrated that tafamidis (Pfizer Inc., New York, NY, USA) reduced all-cause mortality and the number of cardiovascular hospitalizations compared with placebo in patients with transthyretin cardiac amyloidosis. However, the optimal surrogate markers during tafamidis treatment remain unknown.

METHODS

Consecutive patients with transthyretin cardiac amyloidosis who received tafamidis in our institute between May 2019 and December 2022 were retrospectively evaluated. The prognostic impact of an increase in troponin I levels during tafamidis therapy was evaluated.

RESULTS

A total of 18 patients (median age 77 years, 84% male) were included. For 14-month tafamidis therapy on median, cardiac troponin I levels increased in five patients. The cumulative incidence of all-cause hospitalization was significantly higher in the troponin-increased group than in the others (100% versus 33%, p < 0.0001). Troponin increase was independently associated with the cumulative incidence of all-cause hospitalization with an adjusted hazard ratio of 5.14 (95% confidence interval 1.02-25.9, p = 0.048).

CONCLUSIONS

The increase in cardiac troponin levels may be a reasonable surrogate marker of response to tafamidis therapy in patients with transthyretin cardiac amyloidosis.

Conduction system pacing: promoting the physiology to prevent heart failure

Cardiac conduction system pacing provides physiological ventricular activation by directly stimulating the conduction system. This review describes the two types of conduction system pacing: His bundle pacing (HBP) and left bundle area pacing (LBAP). The most significant advantage of HB pacing is that it can provide a regular, narrow QRS; however, the disadvantages are challenging implantation and a high risk of re-intervention due to lead dislodgement and the development of high pacing threshold. LBAP provides optimum physiological activation of the left ventricle by engaging the left bundle/fascicular fibers. LBAP is more physiological than traditional RV apical pacing and could be an attractive alternative to conventional cardiac resynchronization therapy (CRT). The advantages of LBAP are a relatively more straightforward implantation technique than HBP, better lead stability and pacing thresholds. HBP and LBAP are more physiological than right ventricular pacing and may be used instead of conventional pacemakers. Both HBP and LBBP are being investigated as alternatives to conventional CRT.

A new Electromechanical Wave Imaging dispersion metric for the characterization of ventricular activation in different Cardiac Resynchronization Therapy pacing schemes

Conventional biventricular (BiV) pacing cardiac resynchronization therapy (CRT) is an established treatment for heart failure patients. Recently, multiple novel CRT delivering technologies such as His-Bundle pacing have been investigated as alternative pacing strategies for optimal treatment benefit. Electromechanical Wave Imaging (EWI), a high frame-rate echocardiography-based modality, is capable of visualizing the change from dyssynchronous activation to resynchronized BiV-paced ventricles in 3D. This proof-of-concept study introduces a new EWI-based dispersion metric to further characterize ventricular activation. Patients with His-Bundle device implantation (n=4), left-bundle branch block (n=10), right-ventricular (RV) pacing (n=10), or BiV pacing (n=15) were imaged, as well as four volunteers in normal sinus rhythm (NSR). EWI successfully mapped the ventricular activation resulting from His-Bundle pacing. Additionally, very similar activation patterns were obtained in the NSR subjects, confirming recovery of physiological activation with His pacing. The dispersion metric was the most sensitive EWI-based metric that identified His pacing as the most efficient treatment (lowest activation time spread), followed by BiV and RV pacing. More specifically, the dispersion metric significantly (p 0.005) distinguished His pacing from the other two pacing schemes as well as LBBB. The initial findings presented herein indicate that EWI and its new dispersion metric may provide a useful resynchronization evaluation clinical tool in CRT patients under both novel His-Bundle pacing and more conventional BiV pacing strategies.

[ESC guidelines 2021 on cardiac pacing and cardiac resynchronization therapy : What's new?]

The new European Society of Cardiology (ESC) guidelines on cardiac pacing and cardiac resynchronization therapy were presented together with the new ESC heart failure guidelines at the ESC congress in September. The new document includes detailed sections on patient evaluation and clinical assessment, implantation, minimizing complications and patient follow-up. The guidelines have been updated and expanded particularly on the approach to reflex syncope, the indications after transcatheter aortic valve implantation (TAVI) and the perioperative management. The indications for cardiac resynchronization therapy (CRT) are now in line with the simultaneously published ESC heart failure guidelines. New physiological forms of stimulation and leadless pacing are now included in the guidelines.

His Bundle Pacing: A promising alternative strategy for Antibradycardic-pacing. Report of a single center-experience

His Bundle Pacing (HBP) is proven to be a safe and effective alternative pacing modality that, in addition, avoids Pacemaker-induced Cardiomyopathy (PICM) by achieving a ''physiological'' ventricular stimulation, via the native conduction system. Indications include various causes of bradycardia requiring antibradycardic pacing, inadequately controlled Atrial Fibrillation requiring AV node ablation and established PICM. In addition, HBP may also be used as an alternative therapy for patients with Heart Failure (HF) and an indication for Cardiac Resynchronization Therapy. Available data show a benefit from HBP with regard to preservation or restoration of intra- and inter-ventricular synchronization, improvement in Left Ventricular Ejection Fraction, functional status and Quality of Life, decrease in atrial fibrillation incidence and improvement in HF hospitalization rates, compared to conventional pacing. Nevertheless, superiority in terms of mortality rates has not been consistently demonstrated and long-term efficacy and safety remains to be proven. In the present manuscript, we review the status of HBP and we present our current experience with this novel pacing modality.

Physiologic lead placement with electroanatomic mapping: A case series

INTRODUCTION

His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) have emerged as attractive alternatives to traditional biventricular pacing to achieve cardiac resynchronization therapy. Early reported results have been inconsistent, particularly amongst patients in whom initial placement with traditional approaches has been unsuccessful or those with complex anatomy or congenital abnormalities. In this report, we describe the use of three-dimensional electroanatomic mapping (EAM) in five selected cases.

METHODS

Five patients from multiple clinical sites underwent EAM-guided HBP or LBBAP by highly trained electrophysiologists with significant experience with conduction system pacing. Each patient in this series underwent EAM-guided conduction system pacing due to complex anatomy and/or prior failed lead implantation.

RESULTS

EAM-guided lead implantation was successful in all five cases. Capture thresholds were relatively low and patients continued to have evidence of successful lead implantation with minimum 1-month follow-up. The fluoroscopy time varied, likely owing to the variable complexity of the cases.

CONCLUSIONS

The use of EAM, in combination with traditional intracardiac electrograms with or without fluoroscopy, allows more targeted and precise placement of leads for HBP and LBBAP pacing. Further investigation is needed to determine this strategy's long-term performance and to optimize patient selection.

Impact of His bundle pacing on right ventricular performance in patients undergoing permanent pacemaker implantation

BACKGROUND

His-Bundle pacing (HBP) is an emerging technique for physiological pacing. However, its effects on right ventricle (RV) performance are still unknown.

METHODS

We enrolled consecutive patients with an indication for pacemaker (PM) implantation to compare HBP versus RV pacing (RVP) effects on RV performance. Patients were evaluated before implantation and after 6 months by a transthoracic echocardiogram.

RESULTS

A total of 84 patients (age 75.1±7.9 years, 64% male) were enrolled, 42 patients (50%) underwent successful HBP, and 42 patients (50%) apical RVP. At follow up, we found a significant improvement in RV-FAC (Fractional Area Change)% [baseline: HBP 34 IQR (31-37) vs. RVP 33 IQR (29.7-37.2),p = .602; 6-months: HBP 37 IQR (33-39) vs. RVP 30 IQR (27.7-35), p < .0001] and RV-GLS (Global Longitudinal Strain)% [baseline: HBP -18 IQR (-20.2 to -15) vs. RVP -16 IQR (-18.7 to -14), p = .150; 6-months: HBP -20 IQR(-23 to -17) vs. RVP -13.5 IQR (-16 to -11), p < .0001] with HBP whereas RVP was associated with a significant decline in both parameters. RVP was also associated with a significant worsening of tricuspid annular plane systolic excursion (TAPSE) (p < .0001) and S wave velocity (p < .0001) at follow up. Conversely from RVP, HBP significantly improved pulmonary artery systolic pressure (PASP) [baseline: HBP 38 IQR (32-42) mmHg vs. RVP 34 IQR (31.5-37) mmHg,p = .060; 6-months: HBP 32 IQR (26-38) mmHg vs. RVP 39 IQR (36-41) mmHg, p < .0001] and tricuspid regurgitation (p = .005) irrespectively from lead position above or below the tricuspid valve.

CONCLUSIONS

In patients undergoing PM implantation, HBP ensues a beneficial and protective impact on RV performance compared with RVP.

Effects of His bundle pacing and right ventricular apex pacing on cardiac electrical and mechanical synchrony and cardiac function in patients with heart failure and atrial fibrillation

OBJECTIVE

To investigate the effects of right ventricular apex pacing and His bundle pacing on cardiac mechanical and electrical synchrony and cardiac function in patients with heart failure and atrial fibrillation.

METHODS

A total of 72 patients with heart failure and atrial fibrillation who received permanent pacemaker implantation in our hospital were randomly divided into two groups, with 36 patients in each group. The control group received the right ventricular apex pacing, and the study group received His bundle pacing. In the two groups, the pacing parameters, cardiac function, cardiac electricity, mechanical synchrony, complications and living quality were compared.

RESULTS

During operation and 12 months after the operation, the study group's pacing threshold was higher than the pacing threshold of the control group (all P<0.001). Compared with that before the procedure, NYHA grade and LVEDD of the two groups 12 months after operation were decreased (all P<0.001), while LVEF and various quality of life scores were increased (all P<0.001). The study group's NYHA grade and LVEDD were lower than those of the control group 12 months after operation (all P<0.001), while the study group's quality of life scores and LVEF were higher than those of the control group (all P<0.001). Twelve months after operation, the study group's QRS width and IVMD were lower than QRS width and IVMD of the control group (all P<0.001). The study group's complication rate was 5.56% (2/36), which was lower than the control group's complication rate (22.22% (8/36), P<0.05).

CONCLUSION

Compared with right ventricular apical pacing, His bundle pacing in the treatment of heart failure with atrial fibrillation can better maintain the cardiac electrical and mechanical synchronization, promote the recovery of cardiac function, improve living quality, and has fewer complications and significant advantages.

Innovations in Cardiac Implantable Electronic Devices

Cardiac implantable electronic devices (CIEDs) are essential for the management of a variety of cardiac conditions, including tachyarrhythmias, bradyarrhythmias, and medically refractory heart failure (HF). Recent advancements in CIED technology have led to innovative solutions that overcome shortcomings associated with traditional devices or address unmet needs. Leadless pacemakers, subcutaneous implantable cardioverter defibrillators (ICDs), and extravascular ICDs eliminate lead-related complications common with conventional pacemakers or ICDs. Conduction system pacing (His bundle pacing and left bundle branch pacing) is a more physiologic method of pacing and avoids the deleterious consequences associated with long-term right ventricular pacing. For HF-related devices, cardiac contractility modulation is an emerging therapy that bridges a gap for many patients ineligible for cardiac resynchronization therapy and has been shown to improve HF symptoms and decrease hospitalizations and mortality in select patients. Implantable pulmonary artery pressure monitors help guide HF management and reduce hospitalizations. Lastly, new phrenic nerve stimulating devices are being utilized to treat central sleep apnea, a common comorbidity associated with HF. While further long-term studies are still underway for many of these new technologies, it is anticipated that these devices will become indispensable therapeutics in the expanding cardiovascular armamentarium.

His-Purkinje Conduction System Pacing: State of the Art in 2020

Conduction system pacing involves directly stimulating the specialised His-Purkinje cardiac conduction system with the aim of activating the ventricles physiologically, in contrast to the dyssynchronous activation produced by conventional myocardial pacing. Since the first report of permanent His bundle pacing (HBP) in 2000, the stylet-driven technique of its earliest incarnation has been superseded by a more successful stylet-less approach. Widespread uptake has led to a much greater evidence base. Single-centre observational studies have now been supported by large multicentre, international registries, mechanistic studies and the first randomised controlled trials. New evidence has elucidated mechanisms of HBP and illustrated the nature and magnitude of its potential benefits for preventing pacing-induced cardiomyopathy and correcting bundle branch block. Left bundle branch pacing (LBBP) is a newer technique in which the lead is fixed deep into the left side of the intraventricular septum to allow capture of the left bundle, distal to the His bundle. LBBP holds promise as a method for physiological pacing that overcomes some of the fixation, threshold and sensing challenges of HBP. In this state-of-the-art review of His-Purkinje conduction system pacing, the authors assess recent evidence and current practice and explore emerging and future directions in this rapidly evolving field.

A comprehensive individual patient data meta-analysis of the effects of cardiac contractility modulation on functional capacity and heart failure-related quality of life

Aims

Cardiac contractility modulation, also referred to as CCM™, has emerged as a promising device treatment for heart failure (HF) in patients not indicated for cardiac resynchronization therapy. We performed a comprehensive individual patient data meta‐analysis of all non‐confounded prospective randomized controlled trials of CCM vs. control that have measured functional capacity and/or quality of life questionnaires in patients with HF.

Methods and results

The Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE were searched in January 2020 to identify eligible randomized controlled trials. We also asked the sole manufacturer of the device for their list of known trials. Primary outcomes of interest were peak oxygen consumption (peak VO₂), 6 min walk test distance, and quality of life measured by Minnesota Living with Heart Failure Questionnaire (MLWHFQ), and all data were received as individual patient and individual time point data‐points. Mean differences and 95% confidence intervals (CIs) were calculated for continuous data using a fixed‐effects model. Five trials were identified, four randomized studies enrolling 801 participants for all endpoints of interest, and for peak VO₂ alone (n = 60), there was an additional single arm non‐randomized trial (FIX‐HF‐5C2) with a prospective comparison of its 24 week peak VO₂ data compared with the control group of the FIX‐HF‐5C control patients. Pooled analysis showed that, compared with control, CCM significantly improved peak VO₂ (mean difference +0.93, 95% CI 0.56 to 1.30 mL/kg/min, P < 0.00001), 6 min walk test distance (mean difference +17.97, 95% CI 5.48 to 30.46 m, P = 0.005), and quality of life measured by MLWHFQ (mean difference −7.85, 95% CI −10.76 to −4.94, P < 0.00001). As a sensitivity analysis, we excluded the FIX‐HF‐5C2 trial (only relevant for peak VO₂), and the result was similar, mean difference +0.65, 95% CI 0.21 to 1.08 mL/kg/min, P = 0.004.

Conclusions

This comprehensive meta‐analysis of individual patient data from all known randomized trials has shown that CCM provides statistically significant and clinically meaningful benefits in measures of functional capacity and HF‐related quality of life.

Discriminating electrocardiographic responses to His-bundle pacing using machine learning

BACKGROUND

His-bundle pacing (HBP) has emerged as an alternative to conventional ventricular pacing because of its ability to deliver physiological ventricular activation. Pacing at the His bundle produces different electrocardiographic (ECG) responses: selective His-bundle pacing (S-HBP), non-selective His bundle pacing (NS-HBP), and myocardium-only capture (MOC). These 3 capture types must be distinguished from each other, which can be challenging and time-consuming even for experts.

OBJECTIVE

The purpose of this study was to use artificial intelligence (AI) in the form of supervised machine learning using a convolutional neural network (CNN) to automate HBP ECG interpretation.

METHODS

We identified patients who had undergone HBP and extracted raw 12-lead ECG data during S-HBP, NS-HBP, and MOC. A CNN was trained, using 3-fold cross-validation, on 75% of the segmented QRS complexes labeled with their capture type. The remaining 25% was kept aside as a testing dataset.

RESULTS

The CNN was trained with 1297 QRS complexes from 59 patients. Cohen kappa for the neural network's performance on the 17-patient testing set was 0.59 (95% confidence interval 0.30 to 0.88; P <.0001), with an overall accuracy of 75%. The CNN's accuracy in the 17-patient testing set was 67% for S-HBP, 71% for NS-HBP, and 84% for MOC.

CONCLUSION

We demonstrated proof of concept that a neural network can be trained to automate discrimination between HBP ECG responses. When a larger dataset is trained to higher accuracy, automated AI ECG analysis could facilitate HBP implantation and follow-up and prevent complications resulting from incorrect HBP ECG analysis.

His bundle pacing after failure of cardiac resynchronization therapy: a case study

His bundle pacing is a relatively new method of cardiac pacing. This method is used in patients with atrioventricular block to prevent heart failure associated with right ventricular pacing, and in patients with bundle branch block and cardiomyopathy. We report a patient with cardiomyopathy and left bundle branch block with failure of cardiac resynchronization therapy. Permanent His bundle pacing was associated with clinical improvement and improvement of parameters of cardiac function.

High-density mapping-guided corrective HIS bundle pacing after failed CRT upgrade for persistent left superior vena cava

In patients with persistent left superior vena cava (PLSVC), transvenous device implantation for cardiac resynchronization therapy (CRT) may be challenging. We present a complex case with successful, high-density electroanatomic mapping (EAM) guided corrective His bundle pacing (CHBP) following failed CRT upgrade in a patient with PLSVC, congenital heart disease, and pacing-associated heart failure. CHBP restored physiological conduction in left bundle branch block with complete conduction block leading to clinical improvement and cardiac remodeling. The presented case supports the growing evidence that EAM-guided CHBP may be considered a feasible alternative to conventional CRT when venous anatomy is not favorable for left ventricular lead implantation.

How His bundle pacing prevents and reverses heart failure induced by right ventricular pacing

Ideal heart performance demands vigorous systolic contractions and rapid diastolic relaxation. These sequential events are precisely timed and interdependent and require the rapid synchronous electrical stimulation provided by the His-Purkinje system. Right ventricular (RV) pacing creates slow asynchronous electrical stimulation that disrupts the timing of the cardiac cycle and results in left ventricular (LV) mechanical asynchrony. Long-term mechanical asynchrony produces LV dysfunction, remodeling, and clinical heart failure. His bundle pacing preserves synchronous electrical and mechanical LV function, prevents or reverses RV pacemaker-induced remodeling, and reduces heart failure.

Cardiomiopatia Induzida por Estimulação Cardíaca Artificial

Com o advento dos marcapassos cardíacos há mais de 60 anos, iniciou-se a era da estimulação cardíaca artificial, que mudou a história natural das bradicardias sintomáticas, aumentando significativamente a sobrevida principalmente dos pacientes portadores de bloqueio atrioventricular total.

Cardiomyopathy Induced by Artificial Heart Stimulation

With the advent of cardiac pacemakers more than 60 years ago, the era of artificial cardiac pacing began, which changed the natural history of symptomatic bradycardias, significantly increasing the survival especially of patients with complete atrioventricular block.

His Bundle Pacing in Heart Failure-Concept and Current Data

PURPOSE OF REVIEW

His bundle pacing (HBP) has continued to emerge as a viable alternative to both right ventricular pacing (RVP) and cardiac resynchronization therapy. In recent years, a considerable amount of research has been published with regard to using HBP to treat congestive heart failure (CHF) and this article presents a concise yet comprehensive review of this literature.

RECENT FINDINGS

Studies have demonstrated that HBP is useful for CHF patients who are non-responders to biventricular pacing (BiVP) or have a history of previously failed coronary sinus lead placement, right/left bundle branch block cardiomyopathy, or pacing-induced cardiomyopathy. Additionally, HBP is useful in patients with an indication for pacing who are expected to have a RVP burden exceeding 20%. The theoretical benefit of utilizing the native His Purkinje system to excite cardiac tissue is appealing as it can result in true cardiac resynchronization. Limited studies have shown its benefit in reducing heart failure symptoms and improving cardiac function. Larger randomized clinical trials and further investments into developing better technologies are highly desired to make its clinical use sustainable in the long run.

Update in Cardiac Pacing

Initial efforts to artificially stimulate the heart were borne out of a necessity to prevent catastrophic bradycardic events. The initial pacemaker systems were large, bulky external devices. However, advancements in technology allowed for the development of internally powered, fully implantable devices. Further advancements resulted in more complex, programmable devices, but the overall systems have remained largely unchanged for more than 50 years. The most recent advancements in the field have represented fundamental paradigm shifts in both pacemaker design and the approach to cardiac pacing. These efforts have focused on reducing and eliminating hardware to reduce the risk of complications and to focus on improving cardiac efficiency to improve clinical outcomes. In this article, the authors explore these advances including leadless pacemaker systems, permanent His bundle pacing and advances in the field of cardiac resynchronisation therapy.

Adverse Consequences of Right Ventricular Apical Pacing and Novel Strategies to Optimize Left Ventricular Systolic and Diastolic Function

Several studies have focused on the deleterious consequences of Right Ventricular Apical (RVA) pacing on Left Ventricular (LV) function, mediated by pacing-induced ventricular dyssyn-chrony. Therapeutic strategies to reduce the detrimental consequences of RVA pacing have been pro-posed, that includes upgrading of RVA pacing to Cardiac Resynchronization Therapy (CRT), alterna-tive Right Ventricular (RV) pacing sites, minimal ventricular pacing strategies, as well as atrial-based pacing. In developing countries, single chamber RV pacing still constitutes a majority of cases of permanent pacing, and assessment of the optimal RV pacing site is of paramount importance. In chronically-paced patients, it is crucial to maintain as close and normal LV physiological function as possible, by minimizing ventricular dyssynchrony, reducing the chances for heart failure and other complications to develop. This review provides an analysis of the deleterious immediate and long-term consequences of RVA pacing, and the most recent available evidence regarding improvements in pacing options and strategies to optimize LV diastolic and systolic function. Furthermore, the place of advanced echocardiography in the identification of patients with pacing-induced LV dysfunction, the potential role of a new predictor of LV dysfunction in RV-paced subjects, and the long- term out-comes of patients with RV septal pacing will be explored

Transient rise in His-lead threshold due to acute myocardial infarction

An 85-year-old male was admitted to our center with a non-ST elevation myocardial infarction. The patient had a dual-chamber pacemaker in situ with an atrial and His lead. A transient increase in His threshold and loss of nonselective capture occurred at the presentation of right coronary artery infarction, peaking during rotational atherectomy therapy causing loss of capture and complete atrioventricular block. A follow-up interrogation, 2 weeks postrevascularization, showed a return to a normal nonselective capture morphology and threshold measurements. Physicians should be aware of this complication in patients with His leads, particularly those with a history of coronary artery disease.

Arrhythmia & Electrophysiology Review is Now the Official Journal of the British Heart Rhythm Society

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Letter to the Editor: His Bundle Pacing: A New Frontier in the Treatment of Heart Failure

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