Atrioventricular node ablation and His bundle pacing

Outcomes of combined left bundle branch area pacing with atrioventricular nodal ablation in patients with atrial fibrillation and pulmonary disease

INTRODUCTION

Concomitant left bundle branch area pacing (LBBAP) with atrioventricular (AV) nodal ablation is emerging as a viable management option in atrial fibrillation refractory to medical management. Its viability in patients with pulmonary disease and atrial fibrillation is unknown.

METHODS AND RESULTS

This is a retrospective, observational cohort study in consecutive patients who underwent concomitant LBBAP with AV nodal ablation with advanced pulmonary disease at the Cleveland Clinic Fairview Hospital between January 2019 and January 2023. Patient characteristics, comorbidities, and medication use were extracted via chart review. Rates of hospitalizations, medication use, and structural disease seen on echocardiography were compared before and after the procedure. There were 27 patients with group 3 pulmonary hypertension who underwent the procedure. In the 24 months preprocedure, there were 114 admissions for heart failure or atrial fibrillation compared to 9 admissions postprocedure (p < .001). Mean follow up was 17.3 ± 12.1 months. There were no significant complications or lead dislodgements. Echocardiographic characteristics were similar prior to and after pacemaker implantation. Use of medications for rate and rhythm control was common preprocedure, and was reduced dramatically postprocedure.

CONCLUSION

This small, retrospective cohort study suggests concomitant LBBAP with AV nodal ablation may be safe and efficacious for management of atrial fibrillation in patients with advanced pulmonary disease.

"Ablate and Pace" with Conduction System Pacing: Concomitant versus Delayed Atrioventricular Junction Ablation

Objectives: Conduction system pacing (CSP) and atrioventricular junction ablation (AVJA) improve the outcomes in patients with symptomatic, refractory atrial fibrillation (AF). In this setting, AVJA can be performed simultaneously with implantation or in a second procedure a few weeks after implantation. Comparison data on these two alternative strategies are lacking. Methods: A prospective, multicentre, observational study enrolled consecutive patients with symptomatic, refractory AF undergoing CSP and AVJA performed in a single procedure or in two separate procedures. Data on the long-term outcomes and healthcare resource utilization were prospectively collected. Results: A total of 147 patients were enrolled: for 105 patients, CSP implantation and AVJA were performed simultaneously (concomitant AVJA); in 42, AVJA was performed in a second procedure, with a mean of 28.8 ± 19.3 days from implantation (delayed AVJA). After a mean follow-up of 12 months, the rate of procedure-related complications was similar in both groups (3.8% vs. 2.4%; p = 0.666). Concomitant AVJA was associated with a lower number of procedure-related hospitalizations per patient (1.0 ± 0.1 vs. 2.0 ± 0.3; p < 0.001) and with a lower number of hospital treatment days per patient (4.7 ± 1.8 vs. 7.4 ± 1.9; p < 0.001). Conclusions: Concomitant AVJA resulted as being as safe as delayed AVJA and was associated with a lower utilization of healthcare resources.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

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.

Superior approach from the pocket for atrioventricular junction ablation performed at the time of conduction system pacing implantation

BACKGROUND

Conduction system pacing (CSP) and atrioventricular junction ablation (AVJA) improve outcomes in patients with symptomatic, refractory atrial fibrillation (AF). Superior approach (SA) from the pocket via axillary or subclavian vein has been proposed as an alternative to the conventional femoral venous access (FA) to perform AVJA.

OBJECTIVE

To assess the feasibility and safety of SA for AVJA performed simultaneously with CSP, and to compare this approach with FA.

METHODS

A prospective, observational study, enrolling consecutive patients with symptomatic, refractory AF undergoing simultaneous CSP and AVJA.

RESULTS

A total of 107 patients were enrolled: in 50, AVJA was primarily attempted with SA, in 69 from FA. AVJA with SA was successful in 38 patients (76.0%), while in 12 patients, a subsequent FA was required. AVJA from FA was successful in 68 patients (98.5%), while in one patient, a left-sided approach via femoral artery was required. Compared with FA, SA was associated with a significantly longer duration of ablation (238.0 ± 218.2 vs. 161.9 ± 181.9 s; p = .035), a significantly shorter procedure time (28.1 ± 19.8 vs. 19.8 ± 16.8 min; p = .018), an earlier ambulation (2.7 ± 3.2 vs. 19.8 ± 0.1 h; p < .001), and an earlier discharge from procedure completion (24.0 ± 2.7 vs. 27.1 ± 5.1 h; p < .001). After a median follow-up of 12 months, the rate of complications was similar in the two groups (2.0% in SA, 4.3% in FA; p = .483).

CONCLUSION

Simultaneous CSP and AVJA with SA is feasible, with a safety profile similar to FA. Compared to FA, this approach reduces the procedure times and allows earlier ambulation and discharge.

Transvenous left bundle branch pacing during cardiac surgery: A case report

Left bundle branch pacing (LBBP) was a promising physiological pacing method, which could prevent or treat heart failure. We reported a young woman with severe valvular disease and heart failure receiving LBBP under direct vision and without x-ray assistance during cardiac surgery. To the best of our knowledge, this was the first case report of this type of pace maker implantation.

Role of conduction system pacing in ablate and pace strategies for atrial fibrillation

With the advent of conduction system pacing, the threshold for performing 'ablate and pace' procedures for atrial fibrillation has gone down markedly in many centres due to the ability to provide a simple and physiological means of pacing the ventricles. This article reviews the technical considerations for this strategy as well as the current evidence, recognized indications, and future perspectives.

Ablate and pace: Comparison of outcomes between conduction system pacing and biventricular pacing

BACKGROUND

Conduction system pacing (CSP), including His-bundle pacing (HBP) and left bundle branch area pacing (LBBAP), have been proposed as alternatives to biventricular pacing (BVP) in patients scheduled for ablate and pace (A&P) strategy. The aim of this study was to compare the clinical outcomes, including the rate and nature of device-related complications, between BVP and CSP in a cohort of patients undergoing A&P.

METHODS

Prospective, multicenter, observational study, enrolling consecutive patients undergoing A&P. The risk of device-related complications and of heart failure (HF) hospitalization was prospectively assessed.

RESULTS

A total of 373 patients (75.3 ± 8.7 years, 53.9% male, 68.9% with NYHA class ≥III) were enrolled: 263 with BVP, 68 with HBP, and 42 with LBBAP. Baseline characteristics of the three groups were similar. Compared to BVP and HBP, LBBAP was associated with the shortest mean procedural and fluoroscopy times and with the lowest acute capture thresholds (all p < .05). At 12-month follow-up LBBAP maintained the lowest capture thresholds and showed the longest estimated residual battery longevity (all p < .05). At 12-months follow-up the three study groups showed a similar risk of device-related complications (5.7%, 4.4%, and 2.4% for BVP, HBP, and LBBAP, respectively; p = .650), and of HF hospitalization (2.7%, 1.5%, and 2.4% for BVP, HBP, and LBBAP, respectively; p = .850).

CONCLUSIONS

In the setting of A&P, CSP is a feasible pacing modality, with a midterm safety profile comparable to BVP. LBBAP offers the advantage of reducing procedural times and obtaining lower and stable capture thresholds, with a positive impact on the device longevity.

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.

Safety and efficacy of His-Purkinje system pacing in the treatment of patients with atrial fibrillation and heart failure: a systematic review and meta-analysis

Aim

To evaluate the safety and efficacy of the His-Purkinje system pacing (HPCSP) in the treatment of individuals with atrial fibrillation (AF) complicated by heart failure (HF).

Methods

The PubMed, Cochrane Library, Web of Science, and Embase databases were searched through September 1, 2022. The literature was initially screened based on the inclusion and exclusion criteria. The baseline characteristics of the subjects, implantation success rate, New York Heart Association (NYHA) classification, left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDd), QRS duration, pacing threshold, and impedance were extracted and summarized; statistical analysis was performed using RevMan 5.3 software.

Results

In all, 22 articles were included, involving 1,445 patients. Compared to biventricular pacing (BiVP), HPCSP resulted in improved cardiac function, including increased ejection fraction (MD = 5.69, 95% CI: 0.78-10.60, P = 0.02) and decreased LVEDd (MD = -3.50, 95% CI: -7.05-0.05, P = 0.05). It was also correlated with shorter QRS duration (MD = -38.30, 95% CI: -60.71--15.88, P < 0.01) and reduced all-cause mortality and rehospitalization events (RR = 0.72, 95% CI: 0.57-0.91, P < 0.01) in patients. Left bundle branch pacing (LBBP) lowered the pacing threshold (MD = 0.47; 95% CI: 0.25-0.69; P < 0.01), and there was no statistical difference in the rate of endpoint events when comparing these two physiologic pacing modalities (RR = 1.56, 95% CI: 0.87-2.80, P = 0.14).

Conclusion

The safety and efficacy of HPCSP in patients with AF and HF were verified in this meta-analysis. HPCSP can reverse cardiac remodeling and has great clinical application value. Relatively speaking, His-bundle pacing (HBP) can maintain better ventricular electro-mechanical synchronization, and the pacing parameters of LBBP are more stable.

Systematic Review Registration

PROSPERO (CRD42022336109).

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.

The evolving state of cardiac resynchronization therapy and conduction system pacing: 25 years of research at EP Europace journal

Cardiac resynchronization therapy (CRT) was proposed in the 1990s as a new therapy for patients with heart failure and wide QRS with depressed left ventricular ejection fraction despite optimal medical treatment. This review is aimed first to describe the rationale and the physiologic effects of CRT. The journey of the landmark randomized trials leading to the adoption of CRT in the guidelines since 2005 is also reported showing the high level of evidence for CRT. Different alternative pacing modalities of CRT to conventional left ventricular pacing through the coronary sinus have been proposed to increase the response rate to CRT such as multisite pacing and endocardial pacing. A new emerging alternative technique to conventional biventricular pacing, conduction system pacing (CSP), is a promising therapy. The different modalities of CSP are described (Hirs pacing and left bundle branch area pacing). This new technique has to be evaluated in clinical randomized trials before implementation in the guidelines with a high level of evidence.

Pacing of Specialized Conduction System

Right ventricular pacing for bradycardia remains the mainstay of pacing therapy. Chronic right ventricular pacing may lead to pacing-induced cardiomyopathy. We focus on the anatomy of the conduction system and the clinical feasibility of pacing the His bundle and/or left bundle conduction system. We review the hemodynamics of conduction system pacing, the techniques to capture the conduction system and the electrocardiogram and pacing definitions of conduction system capture. Clinical studies of conduction system pacing in the setting of atrioventricular block and after AV junction ablation are reviewed and the evolving role of conduction system pacing is compared with biventricular pacing.

Left Bundle Branch Area Pacing and Atrioventricular Node Ablation in a Single-Procedure Approach for Elderly Patients with Symptomatic Atrial Fibrillation

BACKGROUND

Implantation of a permanent pacemaker and atrioventricular (AV) node ablation (pace-and-ablate) is an established approach for rate and symptom control in elderly patients with symptomatic atrial fibrillation (AF). Left bundle branch area pacing (LBBAP) is a physiological pacing strategy that might overcome right ventricular pacing-induced dyssynchrony. In this study, the feasibility and safety of performing LBBAP and AV node ablation in a single procedure in the elderly was investigated.

METHODS

Consecutive patients with symptomatic AF referred for pace-and-ablate underwent the treatment in a single procedure. Data on procedure-related complications and lead stability were collected at regular follow-up at one day, ten days and six weeks after the procedure and continued every six months thereafter.

RESULTS

25 patients (mean age 79.2 ± 4.2 years) were included and underwent successful LBBAP. In 22 (88%) patients, AV node ablation and LBBAP were performed in the same procedure. AV node ablation was postponed in two patients due to lead-stability concerns and in one patient on their own request. No complications related to the single-procedure approach were observed with no lead-stability issues at follow-up.

CONCLUSIONS

LBBAP combined with AV node ablation in a single procedure is feasible and safe in elderly patients with symptomatic AF.

The role of conduction system pacing in patients with atrial fibrillation

Conduction system pacing (CSP) has emerged as a promising novel delivery method for Cardiac Resynchronisation Therapy (CRT), providing an alternative to conventional biventricular epicardial (BiV) pacing in indicated patients. Despite increasing popularity and widespread uptake, CSP has rarely been specifically examined in patients with atrial fibrillation (AF), a cohort which forms a significant proportion of the heart failure (HF) population. In this review, we first examine the mechanistic evidence for the importance of sinus rhythm (SR) in CSP by allowing adjustment of atrioventricular delays (AVD) to achieve the optimal electrical response, and thus, whether the efficacy of CSP may be significantly attenuated compared to conventional BiV pacing in the presence of AF. We next evaluate the largest clinical body of evidence in this field, related to patients receiving CSP following atrioventricular nodal ablation (AVNA) for AF. Finally, we discuss how future research may be designed to address the vital question of how effective CSP in AF patients is, and the potential hurdles we may face in delivering such studies.

Conduction system pacing in France in 2022: A snapshot survey from the Working Group of Pacing and Electrophysiology of the French Society of Cardiology

BACKGROUND

Conduction system pacing (CSP) is an emerging and promising approach for physiological ventricular pacing. While data from randomized controlled trials are scarce, use of His-bundle pacing (HBP) and left bundle branch area pacing (LBBAP) has increased in France.

AIM

To perform a national snapshot survey for cardiac electrophysiologists to evaluate adoption of CSP in France.

METHODS

An online survey, distributed to every senior cardiac electrophysiologist in France, was conducted in November 2022.

RESULTS

A total of 120 electrophysiologists completed the survey. Eighty-three (69%) respondents reported experience in undertaking CSP procedures and 27 (23%) were planning to start performing CSP in the coming 2 years. The implantation techniques and criteria used for successful implantation differed significantly among operators. The most frequent indications for HBP and LBBAP were high-degree atrioventricular block with left ventricular ejection fraction (LVEF) < 40% (24 and 82%, respectively) or with LVEF ≥ 40% (27 and 74%, respectively), and after failure of a coronary sinus left ventricular lead (27 and 71%, respectively). The limitations respondents most frequently perceived when performing HBP were bad sensing/pacing parameters (45%), increased procedure duration (41%) and risk of lead dislodgement (30%). The most frequently perceived limitations to performing LBBAP were absence of guidelines or consensus (31%), lack of medical training (23%) and increased procedure duration (23%).

CONCLUSIONS

Our national survey-based study supports wide adoption of CSP in France. CSP is currently used as a second-line approach for both antibradycardia and resynchronization indications, with important variations regarding implantation techniques and criteria for measuring success.

Paradigm Shifts in Cardiac Pacing: Where Have We Been and What Lies Ahead?

The history of cardiac pacing dates back to the 1930s with externalized pacing and has evolved to incorporate transvenous, multi-lead, or even leadless devices. Annual implantation rates of cardiac implantable electronic devices have increased since the introduction of the implantable system, likely related to expanding indications, and increasing global life expectancy and aging demographics. Here, we summarize the relevant literature on cardiac pacing to demonstrate the enormous impact it has had within the field of cardiology. Further, we look forward to the future of cardiac pacing, including conduction system pacing and leadless pacing strategies.

Feasibility and safety of both His bundle pacing and left bundle branch area pacing in atrial fibrillation patients: intermediate term follow-up

PURPOSE

His bundle pacing (HBP) improves heart failure (HF) in atrial fibrillation (AF) pacing-dependent patients with a potential for a progressively increased threshold. HBP with right ventricular pacing (RVP) as a backup is always the preferred choice; however, RVP may induce HF. His Purkinje system pacing (HPSP) includes HBP and left bundle branch area pacing (LBBAP). LBBAP maintains left ventricular synchrony but has not been proven to be safe over the long term. We assessed the feasibility and safety of both HBP and LBBAP in AF pacing-dependent patients and compared the parameters of both leads at baseline and at the 6-month follow-up.

METHODS

A total of 16 AF patients in our center, who successfully attempted both HBP and LBBAP, were prospectively enrolled unless only one of these treatment statuses was attained. The electrocardiogram characteristics, leading parameters, echocardiography results, and clinical outcomes were assessed.

RESULTS

Thirteen out of 16 patients achieved both HBP and LBBAP successfully in the same AF pacing-dependent patients. In symptomatic HF patients with preserved left ventricular ejection fraction (LVEF) (n = 10), the left ventricular end-diastolic diameter (LVEDD) was reduced from 51.8 ± 4.4 to 48.3 ± 3.1 mm (p = 0.01) with the use of diuretics, either reduced or stopped (n = 7). During the follow-up, one patient in the group without HF had an increased HBP threshold and developed HF symptoms. His HF symptoms disappeared when switched into LBBAP mode. Another patient in the group with HF got his LVEF elevated by HBP for 3 months by utilizing left bundle branch block(LBBB)correction and continued to increase when switched into LBBAP for another 3 months due to an increased HBP correction threshold. The average unipolar pacing threshold of LBBAP was lower than that of HBP. No perforation or dislodgement occurred in our study.

CONCLUSION

Both HBP and LBBAP could be attempted successfully in the same AF patients when one of the two modes could be adopted and switched according to the clinical feasibility. Compared with HBP, LBBAP yielded better and more stable parameters but showed comparable effects during the 6-month follow-up.

A conversion CRT strategy combined with AVJA may be a perspective alternative for heart failure patients with persistent atrial fibrillation

Heart failure (HF) combined with persistent atrial fibrillation (AF) often coexist and may promote the pathological conditions of cardiac dysfunction, leading to poor prognosis. Cardiac resynchronization therapy (CRT) combined with atrioventricular junction ablation (AVJA) is a highly effective treatment for HF patients with underlying AF who either have failed or are not suitable for catheter ablation. The CRT-AVJA combination therapy can improve clinical outcomes in HF patients. Currently, clinical CRT methods are categorized into biventricular pacing (BVP) - based and conduction system pacing (CSP) - based methods. These procedures have inherent advantages and disadvantages, in addition to their considerable differences in clinical applications. This article aims to review the clinical progress of AVJA combined with different CRT strategies for treating HF patients with persistent AF and propose that conversion CRT strategy (BVP/CSP-CRT) combined with AVJA may be a perspective alternative. Meanwhile, we generalize that 7 categories of HF patients with persistent AF may need to consider the CRT-AVJA combination therapy.

His-bundle pacing and atrioventricular nodal ablation for noncontrolled atrial arrhythmia: A technical challenge with major clinical benefits

BACKGROUND

His-bundle pacing (HBP) is an appealing alternative to right ventricular pacing in patients referred for permanent ventricular pacing and atrioventricular nodal ablation (AVNA) because it preserves physiological ventricular activation. Only limited data regarding HBP combined with AVNA are available in the literature.

OBJECTIVE

The purpose of this study was to provide further evidence on the feasibility and efficacy of this therapeutic approach in patients with uncontrolled atrial arrhythmia.

METHODS

We prospectively included all patients who had undergone AVNA after HBP in 3 different hospitals between 2017 and 2022.

RESULTS

AVNA following HBP lead implantation was performed in 75 patients. Complete atrioventricular (AV) block was obtained in 58 patients (77%), and significant modulation of AV nodal conduction (heart rate <60 bpm) was obtained in 12 patients (16%). AVNA failure was observed in 5 patients (7%). Recording of an atrial signal by the HBP lead was more frequently observed in patients with AVNA modulation/failure than in patients with complete AV block (11/17 vs 5/58; P <.001). No lead dislodgment occurred during the AVNA procedures. Acute His-bundle (HB) capture threshold increase >1 V occurred in 11 patients (15%), with return to baseline value on day 1 in 9 patients. New York Heart Association functional class and left ventricular ejection fraction significantly improved from baseline to last follow-up (3.0 ± 0.7 vs 1.6 ± 0.5; P <.001; and 47% ± 14% vs 60% ± 9%; P <.0001, respectively).

CONCLUSION

AVNA combined with HBP for noncontrolled atrial arrhythmia was feasible and clinically efficient. Implanting the HB lead on the ventricular aspect of the tricuspid annulus avoiding atrial signal recording can facilitate AVNA.

Recruitment of the cardiac conduction system for optimal resynchronization therapy in failing heart

Heart failure (HF) is a leading health burden around the world. Although pharmacological development has dramatically advanced medication therapy in the field, hemodynamic disorders or mechanical desynchrony deteriorated by intra or interventricular conduction abnormalities remains a critical target beyond the scope of pharmacotherapy. In the past 2 decades, nonpharmacologic treatment for heart failure, such as cardiac resynchronization therapy (CRT) via biventricular pacing (BVP), has been playing an important role in improving the prognosis of heart failure. However, the response rate of BVP-CRT is variable, leaving one-third of patients not benefiting from the therapy as expected. Considering the non-physiological activation pattern of BVP-CRT, more efforts have been made to optimize resynchronization. The most extensively investigated approach is by stimulating the native conduction system, e.g., His-Purkinje conduction system pacing (CSP), including His bundle pacing (HBP) and left bundle branch area pacing (LBBAP). These emerging CRT approaches provide an alternative to traditional BVP-CRT, with multiple proof-of-concept studies indicating the safety and efficacy of its utilization in dyssynchronous heart failure. In this review, we summarize the mechanisms of dyssynchronous HF mediated by conduction disturbance, the rationale and acute effect of CSP for CRT, the recent advancement in clinical research, and possible future directions of CSP.

His bundle combined with deep septal left bundle branch area pacing for atrial fibrillation prior to atrioventricular node ablation

Background

To mitigate the risk of dyssynchrony-induced cardiomyopathy, international guidelines advocate His bundle pacing (HBP) with a ventricular backup lead prior to atrioventricular node ablation in treatment-refractory atrial fibrillation and normal left ventricular ejection fraction. As a result of concerns with long-term pacing parameters associated with HBP, this case series reports an adopted strategy of HBP combined with deep septal left bundle branch area pacing (dsLBBAP) in this patient cohort, enabling intrapatient comparison of the two pacing methods.

Methods and Results

Eight patients aged 72 ± 10 years (left ventricular ejection fraction 53 ± 4%) underwent successful combined HBP and dsLBBAP implant prior to AV node ablation. Intrinsic QRS duration was 118 ± 46 ms. When compared to dsLBBAP, HBP had lower sensed ventricular amplitude (2.4 ± 1.1 vs. 15 ± 5.3 V, p = .001) and lower lead impedance (522 ± 57 vs. 814 ± 171ohms, p = .02), but shorter paced QRS duration (101 ± 20 vs. 119 ± 17 ms, p = .02). HBP pacing threshold was 1.0 ± 0.6 V at 1 ms pulse width, and dsLBBAP pacing threshold was 0.5 ± 0.2 V at 0.4 ms pulse width. Five patients underwent cardiac CT showing adequate dsLBBAP ventricular septal penetration (8.6 ± 1.3 mm depth, 2.4 ± 0.5 mm distance from left ventricular septal wall). No complications occurred during a mean follow-up duration of 121 ± 92 days.

Conclusions

Combined HBP and dsLBBAP pacing is a feasible approach as a pace and ablate strategy for atrial fibrillation refractory to medical therapy.

His-bundle pacing vs biventricular pacing following atrioventricular nodal ablation in patients with atrial fibrillation and reduced ejection fraction: A multicenter, randomized, crossover study-The ALTERNATIVE-AF trial

BACKGROUND

Atrioventricular nodal ablation (AVNA) combined with biventricular pacing (BVP) improves outcomes in patients with persistent atrial fibrillation (AF), adequate rate control, and reduced left ventricular ejection fraction (LVEF). His-bundle pacing (HBP) delivers physiological ventricular activation and is a promising alternative to BVP.

OBJECTIVE

The purpose of this trial was to compare HBP with BVP following AVNA.

METHODS

In this multicenter, prospective, randomized crossover trial, we recruited patients with persistent AF and reduced LVEF (≤40%). All patients underwent AVNA and received both HBP and BVP. Patients were randomized to either HBP or BVP for 9 months (phase 1), then were switched to the alternative pacing modality for the next 9 months (phase 2). The primary endpoint was change in LVEF.

RESULTS

Fifty patients (age 64.3 ± 10.3 years; ventricular rate 93.1 ± 19.9 bpm; 72% male) were enrolled. Thirty-eight patients completed the 2 phases and were included in the crossover analysis. A significant improvement in LVEF was observed with HBP compared to BVP (phase 1: ΔLVEFHBP 21.3% and ΔLVEFBVP 16.7%; phase 2: ΔLVEFHBP 3.5% and ΔLVEFBVP -2.4%; Pgeneralizedadditivemodel = 0.015). Significant improvements in left ventricular end-diastolic diameter, New York Heart Association functional class, and B-type natriuretic peptide level were observed with both pacing modalities compared with baseline, whereas no significant differences were observed between HBP and BVP.

CONCLUSION

HBP delivers a modest but significant improvement in LVEF in patients with persistent AF, impaired ventricular function, and narrow QRS duration post-AVNA compared with BVP. Larger long-term trials are required to confirm the additional improvements in function with HBP.

AV-node isolation as an alternative to AV-node ablation in patients undergoing pace & ablate strategy

INTRODUCTION

Atrioventricular (AV)-node ablation (AVNA) is a common therapy option for rate control strategy of permanent atrial fibrillation (AF). We hypothesized that isolation of the AV nodal isolation (AVNI) is associated with a more frequent preservation of an adequate escape rhythm compared to AVNA.

METHODS

This retrospective study included 20 patients with therapy-refractory AF being treated with AVNI and 40 historical AVNA-controls. In AVNI the AV-node region was mapped using a 3D mapping system. Ablation was performed around the previously mapped HIS-cloud regions isolating the atrium from the AV-node. In the AVNI group, ablation was performed with irrigated tip ablation catheter in all cases. The two approaches were compared regarding rate of escape rhythm, delta QRS, and procedural data.

RESULTS

The number of patients with adequate escape rhythm in AVNI was significantly superior to AVNA immediately postoperative (90% vs. 40%, p < 0.01) and during follow-up (77% vs. 36%, p < 0.05). The median change in QRS width was 0 ms in AVNI versus +26 ms in AVNA (p < 0.01). Thirty percent new bundle branch blocks in AVNA were observed compared to 0% in AVNI (p < 0.01). In the AVNI group, fluoroscopy time and total dose area product were significantly lower (p < 0.01).

CONCLUSION

The present study suggests that AV-node isolation using 3D navigation mapping system is a feasible and effective alternative to conventional AVNA. The precise application of radiofrequency lesions preserves a stable AV-junctional rhythm.

Conduction system pacing in everyday clinical practice: EHRA physician survey

With the increasing interest in conduction system pacing (CSP) over the last few years and the inclusion of this treatment modality in the current guidelines, our aim was to provide a snapshot of current practice across Europe. An online questionnaire was sent to physicians participating in the European Heart Rhythm Association research network as well as to national societies and over social media. Data on previous experience with CSP, current indications, preferred tools, unmet needs, and perceptions for the future are reported and discussed.

Right-sided approach to left bundle branch area pacing combined with atrioventricular node ablation in a patient with persistent left superior vena cava and left bundle branch block: a case report

Background

Left bundle branch area pacing (LBBAP) is an alternative to right ventricular (RV) and biventricular (BiV) pacing in patients scheduled for pace and ablate treatment strategy. However, current delivery sheaths are designed for left-sided implantation, making the right-sided LBBAP lead implantation challenging.

Case presentation

We report a case of a right-sided LBBAP approach via right subclavian vein in a heart failure patient with a persistent left superior vena cava scheduled for pace and ablate treatment of refractory atrial flutter. To enable adequate lead positioning and support for transseptal screwing, the delivery sheath was manually modified with a 90-degree curve at the right subclavian vein and superior vena cava junction to allow right-sided implantation. The distance between the reshaping point and the presumed septal region was estimated by placing the sheath on the body surface under fluoroscopy. With the reshaping of the delivery sheath, we were able to achieve LBBAP with relatively minimal torque. Radiofrequency ablation of the atrioventricular node was performed the next day and the pacing parameters remained stable in short-term follow-up.

Conclusion

With the modification of currently available tools, LBBAP can be performed with the right-sided approach.

Feasibility of Left Bundle Branch Area Pacing Combined with Atrioventricular Node Ablation in Atrial Fibrillation Patients with Heart Failure

BACKGROUND

Pacemaker implantation combined with atrioventricular node ablation (AVNA) could be a practical choice for atrial fibrillation (AF) patients with heart failure (HF). Left bundle branch area pacing (LBBaP) has been widely reported.

OBJECTIVES

To explore the safety and efficacy of LBBaP combined with AVNA in AF patients with HF.

METHODS AND RESULTS

Fifty-six AF patients with HF attempted LBBaP and AVNA from January 2019 to December 2020. Standard LBBaP was achieved in forty-six patients, and another ten received left ventricular septal pacing (LVSP). The cardiac function indexes and pacemaker parameters were evaluated at baseline, and we conducted a 1-month and 1-year follow-up.

RESULT

At the time of implantation and 1-month and 1-year follow-up, QRS duration of LVSP group was longer than that of LBBaP group. The pacemaker parameters remained stable in both the LBBaP and LVSP groups. At 1-month and 1-year follow-up after LBBaP and AVNA, left ventricular ejection fraction, left ventricular end-diastolic diameter, and NYHA classification continued to improve. Baseline left ventricular ejection fraction and QRS duration change at implantation can predict the magnitude of improvement of left ventricular ejection fraction at 1-year after LBBaP. Baseline right atrial left-right diameter, the degree of tricuspid regurgitation, and interventricular septum thickness may be the factors affecting the success of LBBaP.

CONCLUSION

LBBaP combined with AVNA is safe and effective for patients with AF and HF. Baseline right atrial left-right diameter, the degree of tricuspid regurgitation, and interventricular septum thickness may be the factors affecting the success of LBBaP.

Left Bundle Branch Pacing Postatrioventricular Junction Ablation for Atrial Fibrillation: Propensity Score Matching With His Bundle Pacing

BACKGROUND

Left bundle branch pacing (LBBP) has emerged as a promising pacing modality to preserve physiological left ventricular activation; however, prospective data evaluating its long-term safety and efficacy in pacemaker-dependent patients following atrioventricular junction (AVJ) ablation are lacking. This study aimed to examine the feasibility, safety, and efficacy of LBBP in patients with atrial fibrillation and heart failure (HF) after AVJ ablation and compare LBBP with His bundle pacing (HBP) through a propensity score (PS) matching analysis.

METHODS

We prospectively enrolled patients with atrial fibrillation and HF referred for AVJ ablation and LBBP between July 2017 and December 2019. The control group was patients selected from HBP implants performed from 2012 to 2019 using PS matching with a 1:1 ratio.

RESULTS

A total of 99 patients were enrolled in the study. The LBBP implant success rate was 100%. Left ventricular ejection fraction improved from baseline 30.3±4.9 to 1-year 47.3±14.5 in HF patients with reduced ejection fraction and from baseline 56.3±12.1 to 1-year 62.3±9.1 in HF patients with preserved ejection fraction (both P<0.001), and left ventricular ejection fraction in both groups remained stable for up to 3 years of follow-up. A threshold increase >2 V at 0.5 ms occurred in only one patient. Of 176 (81.9%) of 215 patients who received permanent HBP post-AVJ ablation, 86 were matched to the LBBP group by 1:1 PS (propensity score matched His bundle pacing, N=86; propensity score matched left bundle branch pacing, N=86). No significant differences in echocardiographic or clinical outcomes were observed between the 2 groups (P>0.05), whereas lower thresholds, greater sensed R-wave amplitudes, and fewer complications were observed in the propensity score matched left bundle branch pacing group (P<0.05).

CONCLUSIONS

LBBP is feasible, safe, and effective in patients with atrial fibrillation and HF post-AVJ ablation and has similar clinical benefits, a higher implant success rate, better pacing parameters, and fewer complications compared with HBP.

Occurrence of ventricular septal perforation in patients with permanent left bundle branch pacing followed up using echocardiographic and computed tomography images

OBJECTIVE

To explore short-term changes after left bundle branch pacing (LBBP) using echocardiography and computed tomography (CT), especially for postoperative ventricular septal perforation.

METHODS

Between January and September 2019, 33 patients with atrioventricular block underwent LBBP at Beijing Anzhen Hospital. All the patients were evaluated using electrocardiography, pacing, parameters and echocardiographic measurements, including for major complications, during the 1, 3, 6, 12 and 24-month follow-up. Interval perforations were examined during a 1-month follow-up echocardiogram and CT.

RESULTS

Left bundle branch pacing was successfully performed in 100% (33/33) of patients. The mean seizure threshold was stable and unchanged postoperatively at the 1, 3, 6, 12 and 24-month follow-up. The paced QRS duration of the LBBP was 119.72 ± 2.53 ms and <130 ms in all patients. Unipolar impedance during the procedure was higher than 500 Ω (662.00 ± 181.50 Ω). No ventricular septal perforation occurred at the end of the procedure. At the 1-month follow-up, two patients reported transthoracic echocardiography, with CT revealing septal lead perforation. Through CT, two other patients were found to have septal lead perforation, and echocardiography indicated that the pacing lead had penetrated the interventricular septum and entered the left subendocardium. At the 1, 3, 6, 12 and 24-month follow-up, these four patients exhibited no significant increase in pacing threshold or impedance (p > .05). No ventricular thrombus or stroke was detected.

CONCLUSION

Permanent LBBP is safe and feasible in patients with bradycardia. Echocardiography and/or CT can more accurately evaluate changes in cardiac structure and function after LBBP.

Biventricular versus Conduction System Pacing after Atrioventricular Node Ablation in Heart Failure Patients with Atrial Fibrillation

Conduction system pacing (CSP) modalities, including His-bundle pacing (HBP) and left bundle branch pacing (LBBP), are increasingly used as alternatives to biventricular (BiV) pacing in heart failure (HF) patients scheduled for pace and ablate strategy. The aim of the study was to compare clinical outcomes of HF patients with refractory AF who received either BiV pacing or CSP in conjunction with atrio-ventricular node ablation (AVNA). Fifty consecutive patients (male 48%, age 70 years (IQR 9), left ventricular ejection fraction (LVEF) 39% (IQR 12)) were retrospectively analysed. Thirteen patients (26%) received BiV pacing, 27 patients (54%) HBP and 10 patients (20%) LBBP. All groups had similar baseline characteristics and acute success rate. While New York Heart. Association (NYHA) class improved in both HBP (p < 0.001) and LBBP (p = 0.008), it did not improve in BiV group (p = 0.096). At follow-up, LVEF increased in HBP (form 39% (IQR 15) to 49% (IQR 16), p < 0.001) and LBBP (from 28% (IQR 13) to 40% (IQR 13), p = 0.041), but did not change in BiV group (p = 0.916). Conduction system pacing modalities showed superior symptomatic and echocardiographic improvement compared to BiV pacing after AVNA. With more stable pacing parameters, LBBP could present a more feasible pacing option compared to HBP.

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.

Physiologic Pacing Targeting the His Bundle and Left Bundle Branch: a Review of the Literature

PURPOSE OF REVIEW

Conduction system pacing (CSP) has emerged as a means to preserve or restore physiological ventricular activation via pacing at the His bundle or at more distal targets in the conduction system, including the left bundle branch area. This review examines strengths, weaknesses, and clinical applications of CSP performed via these approaches.

RECENT FINDINGS

His bundle pacing (HBP) has been successfully utilized for standard bradyarrhythmia indications and for QRS correction among patients receiving devices for cardiac resynchronization therapy (CRT). Limitations of HBP pacing have included implant complexity and rising pacing thresholds over time. Left bundle branch area pacing (LBBAP) appears to deliver similar physiological benefits with shorter implant times and more stable thresholds. More recently, hybrid systems utilizing HBP or LBBAP in combination with left ventricular leads have been used to treat heart failure (HF) patients, and may be useful in multilevel or mixed conduction blocks. There is growing interest in CSP for bradycardia and HF indications, although high quality data with randomized controlled trials are needed to help guide future treatment paradigms.

Generating Evidence to Support the Physiologic Promise of Conduction System Pacing: Status and Update on Conduction System Pacing Trials

Conduction system pacing avoids the potential deleterious effects of right ventricular pacing in patients with bradycardia and provides an alternative approach to cardiac resynchronization therapy. We focus on the available observational and randomized evidence and review studies supporting the safety, feasibility, and physiologic promise of conduction system approaches. We evaluate the randomized data generated from the available clinical trials of conduction system pacing, which have led to the recent inclusion of CSP in international guidelines. The scope for future randomized trials will building on the physiologic promise of conduction system approaches and offering information on clinical end points is explored.

Biventricular versus His bundle pacing after atrioventricular node ablation in heart failure patients with narrow QRS

Background: His bundle pacing (HBP) is a physiological alternative to biventricular (BiV) pacing. We compared short-term results of both pacing approaches in symptomatic atrial fibrillation (AF) patients with moderately reduced left ventricular (LV) ejection fraction (EF ≥35% and <50%) and narrow QRS (≤120 ms) who underwent atrioventricular node ablation (AVNA).Methods: Thirty consecutive AF patients who received BiV pacing or HBP in conjunction with AVNA between May 2015 and January 2020 were retrospectively assessed. Electrocardiographic, echocardiographic, and clinical data at baseline and 6 months after the procedure were assessed.Results: Twenty-four patients (age 68.8 ± 6.5 years, 50% female, EF 39.6 ± 4%, QRS 95 ± 10 ms) met the inclusion criteria, 12 received BiV pacing and 12 HBP. Both groups had similar acute procedure-related success and complication rates. HBP was superior to BiV pacing in terms of post-implant QRS duration, implantation fluoroscopy times, reduction of indexed LV volumes (EDVi 63.8 (49.6-81) mL/m² vs. 79.9 (66-100) mL/m², p = 0.055; ESVi 32.7 (25.6-42.6) mL/m² vs. 46.4 (42.9-68.1) mL/m², p = 0.009) and increase in LVEF (46 (41-55) % vs. 38 (35-42) %, p = 0.005). However, the improvement of the NYHA class was similar in both groups.Conclusions: In symptomatic AF patients with moderately reduced EF and narrow QRS undergoing AVNA, HBP could be a conceivable alternative to BiV pacing. Further prospective studies are warranted to address the outcomes between both 'ablate and pace' strategies.

Conduction System Pacing versus Conventional Pacing in Patients Undergoing Atrioventricular Node Ablation: Non-randomized, On-Treatment Comparison

Background

Atrioventricular node ablation (AVNA) with right ventricular or biventricular pacing (conventional pacing; CP) is an effective therapy for patients with refractory atrial fibrillation (AF). Conduction system pacing (CSP) using His bundle pacing or left bundle branch area pacing preserves ventricular synchrony.

Objective

The aim of our study is to compare the clinical outcomes between CP and CSP in patients undergoing AVNA.

Methods

Patients undergoing AVNA at Geisinger Health System between January 2015 and October 2020 were included in this retrospective observational study. CP or CSP was performed at the operators’ discretion. Procedural, pacing parameters, and echocardiographic data were assessed. Primary outcome was the combined endpoint of time to death or heart failure hospitalization (HFH) and was analyzed using Cox proportional hazards. Secondary outcomes were individual outcomes of time to death and HFH.

Results

AVNA was performed in 223 patients (CSP, 110; CP, 113). Age was 75 ± 10 years, male 52%, hypertension 67%, diabetes 25%, coronary disease 40%, and left ventricular ejection fraction (LVEF) 43% ± 15%. QRS duration increased from 103 ± 30 ms to 124 ± 20 ms (P < .01) in CSP and 119 ± 32 ms to 162 ± 24 ms in CP (P < .001). During a mean follow-up of 27 ± 19 months, LVEF significantly increased from 46.5% ± 14.2% to 51.9% ± 11.2% (P = .02) in CSP and 36.4% ± 16.1% to 39.5% ± 16% (P = .04) in CP. The primary combined endpoint of time to death or HFH was significantly reduced in CSP compared to CP (48% vs 62%; hazard ratio 0.61, 95% confidence interval 0.42–0.89, P < .01). There was no reduction in the individual secondary outcomes of time to death and HFH in the CSP group compared to CP.

Conclusion

CSP is a safe and effective option for pacing in patients with AF undergoing AVNA in high-volume centers.

The clinical utility of direct His-bundle pacing in patients with heart failure and permanent atrial fibrillation

In patients with significantly impaired left ventricle function permanent atrial fibrillation (AF) often coexists with symptoms of heart failure. Based on various studies, it is assumed that in patients with heart failure in functional class III and IV AF occurs in 40-50% of patients. AF adversely affects cardiac hemodynamics, and its harmfulness increases particularly in the failing heart. The lack of mechanical function of the left atrium, the usually fast ventricular rate and the irregular sequence of ventricular contraction constitute the spectrum of harmful effects of this arrhythmia. Therefore, the only way to address the underlying problem of AF, which is irregular ventricular rhythm, is to pace the ventricles and to slow or block the AV conduction. Classic, right ventricular pacing is contraindicated in this population as it promotes the abovementioned disorders by initiating additional dyssynchrony of left ventricular contraction with reduction of its contractility and aggravation of AF-related mitral regurgitation. The possibility of direct His bundle pacing (DHBP) significantly extended the clinical armamentarium of cardiac pacing. The restoration of the physiological electrical activation could significantly contribute to echocardiographic and clinical improvement. With time and the development of dedicated tools for direct His bundle pacing the success rate of implantations became more than 90% and the acceptable pacing thresholds under 2.0 V (1 ms) could be achieved in most patients. This contributed to the broader clinical application of DHBP in different patient' groups with various pacing indications. The authors of the paper discuss different electrocardiographic and clinical indications for DHBP.

Therapeutic Effect of His-Purkinje System Pacing Proportion on Persistent Atrial Fibrillation Patients With Heart Failure

Background

His-Purkinje system pacing (HPSP) combined with atrioventricular node ablation is an effective therapy for atrial fibrillation (AF) patients with heart failure (HF). However, atrioventricular node ablation has some limitations and disadvantages. HPSP combined with β -blockers reduces intrinsic heart rate and increases pacing proportion, which may be an alternative to HPSP combined with atrioventricular node ablation. This study was to assess the therapeutic effect of different HPSP proportion on AF patients with HF.

Methods

The study enrolled 30 consecutive persistent AF patients with HF who underwent HPSP. Heart rate was controlled by medical therapy. NYHA class, NT-proBNP, echocardiographic parameters were assessed at follow-up. MACE was defined as the composite endpoint of readmission for HF and cardiac mortality.

Results

The AUC of pacing proportion for predicting MACE was 0.830 (SE = 0.140, 95%CI:0.649–0.941, p = 0.018), the optimal cut-off point of pacing proportion to predict MACE by ROC analysis was 71% (sensitivity:83.3%, specificity: 91.7%). In high pacing proportion group (&gt;71%), there were significant improvements of NYHA class, NT-proBNP, LVEF and LVEDD from the baseline in wide QRS complex (QRSd&gt;120 ms) patients and HFrEF patients at half year follow-up, and there were significant improvements in NYHA class, NT-proBNP from baseline in narrow QRS complex (QRSd ≤ 120 ms) patients and HFpEF patients at half year follow-up, moderate but no significant improvements of LVEF and LVEDD were observed in these patients. In low pacing proportion group (≤ 71%), there were no significant improvements of NT-proBNP, LVEDD or LVEF regardless of baseline QRS duration or LVEF (p &gt; 0.05).

Conclusion

High pacing proportion (&gt;71%) of HPSP can improve clinical outcomes and echocardiographic parameters in persistent AF patients with wide QRS complex or HFrEF, and clinical outcomes in persistent AF patients with narrow QRS complex or HFpEF. High pacing proportion of HPSP has a beneficial effect on the prognosis of persistent AF patients with HF.

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.

Pacing of Specialized Conduction System

Right ventricular pacing for bradycardia remains the mainstay of pacing therapy. Chronic right ventricular pacing may lead to pacing-induced cardiomyopathy. We focus on the anatomy of the conduction system and the clinical feasibility of pacing the His bundle and/or left bundle conduction system. We review the hemodynamics of conduction system pacing, the techniques to capture the conduction system and the electrocardiogram and pacing definitions of conduction system capture. Clinical studies of conduction system pacing in the setting of atrioventricular block and after AV junction ablation are reviewed and the evolving role of conduction system pacing is compared with biventricular pacing.

His-optimized cardiac resynchronization therapy in a patient with heart failure and right bundle branch block: a case report

Background 

Cardiac resynchronization therapy (CRT) is an option for treatment for chronic heart failure (HF) associated with left bundle branch block (LBBB). Patients with HF and right bundle branch block (RBBB) have potentially worse outcomes in comparison to LBBB. Traditional CRT in RBBB can increase mortality and HF deterioration rates over native disease progression. His bundle pacing may improve the results of CRT in those patients. Furthermore, atrioventricular node ablation (AVNA) for rate control in atrial fibrillation (AF) can be challenging in patients with previously implanted leads in His region.

Case summary 

We report the case of 74-year-old gentleman with a 5-year history of HF, permanent AF with a rapid ventricular response, and RBBB. He was admitted to the hospital with complaints of severe weakness and shortness of breath. Left ventricular ejection fraction (LVEF) was decreased (41%), right ventricle (RV) was dilated (41 mm), and QRS was prolonged (200 ms) with RBBB morphology. The patient underwent His-optimized CRT with further left-sided AVNA. As a result, LVEF increased to 51%, RV dimensions decreased to 35 mm with an improvement of the clinical status during a 6-month follow-up.

Discussion 

Patients with AF, RBBB, and HF represent the least evaluated clinical subgroup of individuals with less beneficial clinical outcomes according to CRT studies. Achieving the most effective resynchronization could require pacing fusion from sites beyond traditional with the intention to recruit intrinsic conduction pathways. This approach can be favourable for reducing RV dilatation, improving LVEF, and maximizing electrical resynchronization.