Benefits of Permanent His Bundle Pacing Combined With Atrioventricular Node Ablation in Atrial Fibrillation Patients With Heart Failure With Both Preserved and Reduced Left Ventricular Ejection Fraction

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 (>71%), there were significant improvements of NYHA class, NT-proBNP, LVEF and LVEDD from the baseline in wide QRS complex (QRSd>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 > 0.05).

Conclusion

High pacing proportion (>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.

Clinical Outcomes Associated With His-Purkinje System Pacing vs. Biventricular Pacing, in Cardiac Resynchronization Therapy: A Meta-Analysis

Aims

His-Purkinje system pacing has recently emerged as an alternative to biventricular pacing (BIVP) in cardiac resynchronization therapy (CRT). The aim of this study was to conduct a meta-analysis comparing the clinical outcomes associated with His-Purkinje system pacing (HPSP) vs. BIVP in patients with heart failure. There is also a comparison of clinical outcomes of His-bundle pacing (HBP) and left bundle branch pacing (LBBP) in the His-Purkinje system.

Methods

We searched the Cochrane Library, Embase, and PubMed, for studies published between January 2010 and October 2021 that compared the clinical outcomes associated with HPSP vs. BIVP and HBP vs. LBBP in HPSP in patients who underwent CRT. The pacing threshold, R-wave amplitudes, QRS duration, New York Heart Association functional (NYHA), left ventricular ejection fraction (LVEF), and LV end-diastolic diameter (LVEDD) of heart failure, at follow-up, were extracted and summarized for meta-analysis.

Results

A total of 18 studies and 1517 patients were included in our analysis. After a follow-up period of 9.3 ± 5.4 months, the HPSP was found to be associated with shorter QRS duration in the CRT population compared to that in the BIVP (SMD, −1.17; 95% CI, −1.56 to −0.78; P < 0.00001; I2 = 74%). No statistical difference was verified between HBP and LBBP on QRS duration (SMD, 0.04; 95% CI, −0.32 to 0.40; P = 0.82; I2 = 84%). In the comparison of HPSP and BIVP, the LBBP subgroup showed improved LVEF (SMD, 0.67; 95% CI, 0.42–0.91; P < 0.00001; I2 = 0%), shorter LVEDD (SMD, 0.59; 95% CI, 0.93–0.26; P = 0.0005; I2 = 0%), and higher New York Heart Association functional class (SMD, −0.65; 95% CI, −0.86 to −0.43; P < 0.00001; I2 = 45%). In terms of pacing threshold and R-wave amplitude clinical outcomes, LBBP has a lower pacing threshold (SMD, 1.25; 95% CI, 1.12–1.39; P < 0.00001; I2 = 47%) and higher R-wave amplitude (MD, −7.88; 95% CI, −8.46 to −7.31; P < 0.00001; I2 = 8%) performance compared to HBP.

Conclusion

Our meta-analysis showed that the HPSP produced higher LVEF, shorter QRS duration, and higher NYHA functional class in the CRT population than the BIVP as observed on follow-up. LBBP has a lower pacing threshold and higher R-wave amplitude. HPSP may be a new and promising alternative to BIVP in the future.

Pacemaker and Atrioventricular Junction Ablation in Patients With Atrial Fibrillation—A Systematic Review of Systematic Review and Meta-Analysis

Background

Cardiac resynchronization therapy (CRT) could be considered for heart failure (HF) patients with atrial fibrillation (AF) unless a potent ventricular capture strategy is conducted. However, the benefit of a pacemaker (PM; as part of CRT) in patients with AF and whether atrioventricular junction (or nodal) ablation (AVAB) can improve the prognosis of these patients compared with those treated medically to support ventricular capture are unclear.

Methods and Results

Systematic reviews and meta-analyses investigating the roles of PMs and AVAB in patients with AF were obtained in a search of the PubMed, Embase, and Medline databases and then analyzed with respect to the following outcomes: mortality, left ventricular ejection fraction, and clinical findings including the New York Heart Association class, 6-min walk distance (6MWD), quality of life as assessed in a specific questionnaire, and response to CRT. The quality of the included reviews was assessed using the Assessing the Methodological Quality of Systematic Reviews 2 tool, which includes 16 items. This study was finally based on 13 systematic reviews or meta-analyses. The results showed that patients with AF have higher all-cause mortality rates compared with patients with sinus rhythm and that AVAB can reduce all-cause mortality in patients with AF. Although the functional improvement was better in sinus rhythm than in patients with AF, in the latter, AVAB increased the 6MWD and reduced the CRT nonresponse rate in patients with AF.

Conclusion

Atrial fibrillation is associated with a higher all-cause mortality rate in patients with CRT implantation. AVAB, by increasing the 6MWD and survival, can improve the prognosis of these patients.

Permanent His-bundle pacing in the right atrium in a patient with a Mobitz II atrioventricular block: a case presentation

Background

This case report presents a patient diagnosed with sick sinus syndrome who was successfully treated with permanent His-bundle pacing (PHBP).

Case presentation

A 36-year-old man was transferred to our hospital due to recurrent syncope. He was diagnosed with sick sinus syndrome based on the 24-h Holter and a history of syncope. He was admitted to hospital and successfully treated with PHBP. The postoperative examination showed that the pacing rhythm, pacemaker pacing and perception function were normal. He was discharged without any complications after a successful pacemaker implantation.

Conclusions

We described a case in which PHBP may become an optimal approach to the management of patients with sick sinus syndrome. Right ventricular pacing has been attempted with inconsistent efficacy outcomes. HBP provides a promising alternative pacing option that might provide symptom resolution to patients with sick sinus syndrome.

Comparison of the Acute Effects of Different Pacing Sites on Cardiac Synchrony and Contraction Using Speckle-Tracking Echocardiography

Background: Cardiac pacing in patients with bradyarrhythmia may employ variable pacing sites, which may have different effects on cardiac function. Left bundle branch pacing (LBBP) is a new physiological pacing modality, and the acute outcomes on cardiac mechanical synchrony during LBBP remain uncertain. We evaluated the acute effects of four pacing sites on cardiac synchrony and contraction using speckle-tracking echocardiography, and comparisons among four different pacing sites were rare.

Methods: We enrolled 21 patients with atrioventricular block or sick sinus syndrome who each sequentially underwent acute pacing protocols, including right ventricular apical pacing (RVAP), right ventricular outflow tract pacing (RVOP), His bundle pacing (HBP), and left bundle branch pacing (LBBP). Electrocardiograms and echocardiograms were recorded at baseline and during pacing. The interventricular mechanical delay (IVMD), the standard deviation of the times to longitudinal peak strain during 17 segments (PSD), and the Yu index were used to evaluate ventricular mechanical synchrony. Layer-specific strain was computed using two-dimensional speckle tracking technique to provide in-depth details about ventricular synchrony and function.

Results: Left ventricular ejection fraction (LVEF) and tricuspid annulus plane systolic excursion (TAPSE) were significantly decreased during RVAP and RVOP but were not significantly different during HBP and LBBP compared with baseline. RVAP and RVOP significantly prolonged QRS duration, whereas HBP and LBBP showed non-significant effects. IVMD and PSD were significantly increased during RVAP but were not significantly different during RVOP, HBP, or LBBP. LBBP resulted in a significant improvement in the IVMD and Yu index compared with RVAP. No significant differences in mechanical synchrony were found between HBP and LBBP.

Conclusion: Among these pacing modalities, RVAP has a negative acute impact on cardiac synchrony and contraction. HBP and LBBP best preserve physiological cardiac synchrony and function.

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.

Left bundle branch area pacing versus right ventricular pacing in patients with persistent atrial fibrillation requiring ventricular pacing

PURPOSE

This study aims to assess whether left bundle branch area pacing (LBBAP) can result in favorable clinical and echocardiographic outcomes among patients with persistent atrial fibrillation (PeAF).

METHODS

We prospectively enrolled consecutive patients with PeAF if they required ventricular pacing and had left ventricular ejection fraction (LVEF) > 35%. During the same period, two experienced operators performed LBBAP and right ventricular pacing (RVP). All-cause death and heart failure hospitalization (HFH) were routinely followed after procedure. The primary outcome was the composite endpoints of all-cause death or HFH.

RESULTS

LBBAP was successful in 49 of 52 patients (94.2%), whereas 44 patients received RVP. During a mean follow-up of 13.9 ± 7.0 months, LBBAP group presented with higher ventricular pacing percentage (80% vs. 50.9%, p = .04) and narrower paced QRS duration (117.2 ± 18.8 ms vs. 151.8 ± 13.7 ms, p < .001) than RVP group. The primary endpoint was slightly reduced in LBBAP group than RVP without reaching statistical significance (7.7% vs. 11.4%, p = .48). Compared with baseline, we observed significant changes in LVEF (+0.7% vs. -2.2%, p = .007) and left atrial diameter (-1.63 mm vs. +1.23 mm, p = .011) between LBBAP and RVP.

CONCLUSION

Our results indicate possible effect of LBBAP on reverse remodeling of left atrium and a trend towards favorable clinical outcomes in patients with PeAF requiring high burden of ventricular pacing when compared with RVP.

Case Report: Interventricular Septal Hematoma Complicating Left Bundle Branch Pacing Lead Implantation

Background: Left bundle branch pacing (LBBP) is a novel physiological pacing and previous studies have confirmed the feasibility and safety of it. The incidence of complications in LBBP is relatively low as reported. Here we present a case of interventricular septal hematoma complicating LBBP lead implantation.

Case summary: LBBP was achieved for treatment of high-grade atrioventricular block in a 67-year-old female. Chest pain began 1 h after implantation when the electrocardiogram showed ST-T changes. Then bedside echocardiography confirmed the formation of interventricular septal hematoma. Urgent coronary angiography showed the contrast agent retention and overflow in the interventricular septum. The symptom was relieved half an hour later. Echocardiogram performed 2 h later revealed the size of the hematoma was the same as before. The electrocardiography, coronary angiography and CTA confirmed the resolution of the hematoma at 1-month follow-up. Pacing parameters and cardiac function remained stable during 6-month follow-up.

Conclusion: This is the first reported case describing the clinic features and management of interventricular septum hematoma complicating LBBP. The importance of routine echocardiograms after implantation for identifying the hematoma should be highlighted.

Device-Based Solutions to Improve Cardiac Physiology and Hemodynamics in Heart Failure With Preserved Ejection Fraction

Characterized by a rapidly increasing prevalence, elevated mortality and rehospitalization rates, and inadequacy of pharmaceutical therapies, heart failure with preserved ejection fraction (HFpEF) has motivated the widespread development of device-based solutions. HFpEF is a multifactorial disease of various etiologies and phenotypes, distinguished by diminished ventricular compliance, diastolic dysfunction, and symptoms of heart failure despite a normal ejection performance; these symptoms include pulmonary hypertension, limited cardiac reserve, autonomic imbalance, and exercise intolerance. Several types of atrial shunts, left ventricular expanders, stimulation-based therapies, and mechanical circulatory support devices are currently under development aiming to target one or more of these symptoms by addressing the associated mechanical or hemodynamic hallmarks. Although the majority of these solutions have shown promising results in clinical or preclinical studies, no device-based therapy has yet been approved for the treatment of patients with HFpEF. The purpose of this review is to discuss the rationale behind each of these devices and the findings from the initial testing phases, as well as the limitations and challenges associated with their clinical translation.

Is His-optimized superior to conventional cardiac resynchronization therapy in improving heart failure? Results from a propensity-matched study

BACKGROUND

His bundle pacing (HBP), alone or optimized in association with coronary sinus pacing (HBP+LV) has recently been proposed as an alternative to conventional cardiac resynchronization therapy (CRT). However, there is lack of controlled studies that assessed clinical outcome.

METHODS

We did a single-center, propensity-score matched, case-control study of comparison of HBP and HBP+LV versus conventional CRT in patients with heart failure (HF) and standard indications for CRT. The study group patients were consecutively enrolled in the year 2019. The control group patients were selected, by propensity score matching, among those CRT implantations performed in the years 2015-2018.

RESULTS

There were 27 patients in each group. In the active group, 12 (44%) patients received HBP alone and 12 (44%) patients HBP+LV pacing. HBP failed in three (11%) patients. In the control group, conventional CRT was achieved in 26 (96%) patients and failed in one. Paced QRS width was shorter in the active than in the control group (128 ± 18 vs. 148 ± 27 ms, p = .004). During a mean of 9.6 months of follow-up, a composite clinical outcome of death, hospitalization for HF or worsening HF occurred in three (11%) in the active group and in four (15%) in the control group, p = .58. No difference was also observed with softer endpoints: NYHA class (1.9 ± 0.7 vs. 2.1 ± 0.7), subjective improvement (74% vs. 74%) and LV ejection fraction (40.7% vs. 40.7%).

CONCLUSION

Compared with conventional CRT, a shorter QRS width can be obtained with HBP alone or in association with coronary sinus pacing but we were unable to show a better clinical outcome. There is urgent need for large, randomized trials.

Cryoablation vs. radiofrequency ablation of the atrioventricular node in patients with His-bundle pacing

AIMS

Radiofrequency ablation (RFA) of the atrioventricular node (AVN) with His-bundle pacing (HBP) can cause rise in capture thresholds. Cryoablation (CRYO) may offer reversibility in case of threshold rise but has never been tested for AVN ablation in this setting. Our aim was to compare procedural characteristics and outcome of CRYO compared with RFA for AVN ablation in patients with HBP.

METHODS AND RESULTS

Forty-four patients with HBP underwent AVN ablation for an 'ablate and pace' indication. Cryoablation was performed in the first 22 patients and RFA in the following 22 patients. Procedural characteristics, success rates, and change in His capture thresholds were compared between groups. Distance from the ablation site to the His lead was measured using biplane fluoroscopy. Acute success was 100% with both strategies. Median procedural duration was significantly longer for CRYO {50 [interquartile range (IQR) 38-63] min} compared with RFA [36 (IQR, 30-41) min; P = 0.027]. An acute threshold rise of ≥1 V was observed in four CRYO (one complete loss of capture) and three RFA patients (P = 0.38), with all of the applications being within 6 mm of the His lead tip. During follow-up, nine patients had AVN re-conduction (six CRYO vs. three RFA; P = 0.58), but only four patients required a redo procedure (all CRYO; P = 0.09).

CONCLUSION

Cryoablation does not offer any advantage over RFA for AVN ablation in patients with HBP and tended to require more redo procedures. If possible, a distance of ≥6 mm should be maintained from the His lead tip to avoid a rise in capture thresholds.

Feasibility and Safety of Left Bundle Branch Pacing for Advance Aged Patients: A Multicenter Comparative Study

Background: Left bundle branch pacing (LBBP) has been shown to be a safe and effective means to achieve physiological pacing. However, elderly patients have increased risks from invasive procedures and the risk of LBBP in elderly patients is not known. We aimed to investigate the safety and efficacy of LBBP in elderly patients >80 years of age.

Methods: From December 2017 to June 2019, 346 consecutive patients with symptomatic bradycardia, 184 patients under 80 years of age and 162 over 80 years, were included and underwent LBBP. The safety and prognosis of LBBP were comparatively evaluated by measured pacing parameters, periprocedural complications, and follow-up clinical events.

Results: Compared with the younger, the elderly group had worse baseline cardiac and renal function. LBBP was achieved successfully in both groups with comparable fluoroscopic time and paced QRS duration (110.0 [102.0, 118.0] ms for the young vs. 110.0 [100.0, 120.0] ms for the elderly, P = 0.874). Through a follow-up of 20.0 ± 6.1 months, pacing parameters were stable while higher threshold and impedance were observed in the elderly group. In the evaluation of safety, overall procedure-related complication rates were comparable (4.4 vs. 3.8%, young vs. elderly). For prognosis, similar rates of major adverse cardiocerebrovascular events (7.1 vs. 11.9%, young vs. elderly) were observed.

Conclusions: Compared to younger patients, LBBP could achieve physiological pacing in patients over 80 with comparable midterm safety and prognosis. Long-term safety and benefits of LBBP, however, necessitate further evaluation.

Long-term performance and risk factors analysis after permanent His-bundle pacing and atrioventricular node ablation in patients with atrial fibrillation and heart failure

AIMS

His-bundle pacing (HBP) combined with atrioventricular node (AVN) ablation has been demonstrated to be effective in patients with atrial fibrillation (AF) and heart failure (HF) during medium-term follow-up and there are limited data on the risk analysis of adverse prognosis in this population. In this study, we aimed to evaluate the long-term performance of HBP following AVN ablation in AF and HF.

METHODS AND RESULTS

From August 2012 to December 2017, consecutive AF patients with HF and narrow QRS who underwent AVN ablation and HBP were enrolled. The clinical and echocardiographic data, pacing parameters, all-cause mortality, and heart failure hospitalization (HFH) were tracked. A total of 94 patients were enrolled (age 70.1 ± 10.5 years; male 57.4%). Acute HBP were achieved in 89 (94.7%) patients with successful permanent HBP combined with AVN ablation in 81 (86.2%) patients. Left ventricular ejection fraction (LVEF) improved from 44.9 ± 14.9% at baseline to 57.6 ± 12.5% during a median follow-up of 3.0 (IQR: 2.0-4.4) years (P < 0.001). Heart failure hospitalization or all-cause mortality occurred in 21 (25.9%) patients. The LVEF ≤ 40%, pulmonary artery systolic pressure (PASP) ≥40 mmHg, or serum creatinine (Scr) ≥97 μmol/L at baseline was significantly associated with higher composite endpoint of HFH or death (P < 0.05). The His capture threshold was 1.0 ± 0.7 V/0.5 ms at implant and remained stable during follow-up.

CONCLUSION

His-bundle pacing combined with AVN ablation was effective in patients with AF and drug-refectory HF. High PASP, high Scr, or low LVEF at baseline was independent predictors of composite endpoint of all-cause mortality or HFH.

Feasibility and Outcomes of Upgrading to Left Bundle Branch Pacing in Patients With Pacing-Induced Cardiomyopathy and Infranodal Atrioventricular Block

His bundle pacing (HBP) can reverse left ventricular (LV) remodeling in patients with right ventricular (RV) pacing-induced cardimyopathy (PICM) but may be unable to correct infranodal atrioventricular block (AVB). Left bundle branch pacing (LBBP) results in rapid LV activation and may be able to reliably pace beyond the site of AVB. Our study was conducted to assess the feasibility, safety, and outcomes of permanent LBBP in infranodal AVB and PICM patients. Patients with infranodal AVB and PICM who underwent LBBP for cardiac resynchronization therapy (CRT) were included. Clinical evaluation and echocardiographic and electrocardiographic assessments were recorded at baseline and follow-up. Permanent LBBP upgrade was successful in 19 of 20 patients with a median follow-up duration of 12 months. QRS duration (QRSd) increased from 139.3 ± 28.0 ms at baseline to 176.2 ± 21.4 ms (P < 0.001) with right ventricular pacing (RVP) and was shortened to 120.9 ± 15.2 ms after LBBP (P < 0.001). The mean LBBP threshold was 0.7 ± 0.3 V at 0.4 ms at implant and remained stable during follow-up. The left ventricular ejection fraction (LVEF) increased from 36.3% ± 6.5% to 51.9% ± 13.0% (P < 0.001) with left ventricular end-systolic volume (LVESV) reduced from 180.1 ± 43.5 to 136.8 ± 36.7 ml (P < 0.001) during last follow-up. LBBP paced beyond the site of block, which results in a low pacing threshold with a high success rate in infranodal AVB patients. LBBP improved LV function with stable parameters over the 12 months, making it a reasonable alternative to cardiac resynchronization pacing via a coronary sinus lead in infranodal AVB and PICM patients.

A network meta-analysis and systematic review of change in QRS duration after left bundle branch pacing, His bundle pacing, biventricular pacing, or right ventricular pacing in patients requiring permanent pacemaker

Cardiac dyssynchrony is the proposed mechanism for pacemaker-induced cardiomyopathy, which can be prevented by biventricular pacing. Left bundle branch pacing and His bundle pacing are novel interventions that imitate the natural conduction of the heart with, theoretically, less interventricular dyssynchrony. One of the surrogate markers of interventricular synchrony is QRS duration. Our study aimed to compare the change of QRS duration before and after implantation between types of cardiac implantable electronic devices (CIEDs): left bundle branch pacing versus His bundle pacing versus biventricular pacing and conventional right ventricular pacing. A literature search for studies that reported an interval change of QRS duration after CIED implantation was conducted utilizing the MEDLINE, EMBASE, and Cochrane databases. All relevant works from database inception through November 2020 were included in this analysis. A random-effects model, Bayesian network meta-analysis was used to analyze QRS duration changes (eg, electrical cardiac synchronization) across different CIED implantations. The mean study sample size, from 14 included studies, was 185 subjects. The search found 707 articles. After exclusions, 14 articles remained with 2,054 patients. The His bundle pacing intervention resulted in the most dramatic decline in QRS duration (mean difference, - 53 ms; 95% CI - 67, - 39), followed by left bundle branch pacing (mean difference, - 46 ms; 95% CI - 60, - 33), and biventricular pacing (mean difference, - 19 ms; 95% CI - 37, - 1.8), when compared to conventional right ventricle apical pacing. When compared between LBBP and HBP, showed no statistically significant wider QRS duration in LBBP with mean different 6.5 ms. (95% CI - 6.7, 21). Our network meta-analysis found that physiologic pacing has the greatest effect on QRS duration after implantation. Thus, HBP and LBBP showed no significant difference between QRS duration after implantation. Physiologic pacing interventions result in improved electrocardiography markers of cardiac synchrony, narrower QRS duration, and might lower electromechanical dyssynchrony.

Brady-arrhythmias in patients with atrial fibrillation and heart failure of reduced ejection fraction: is his-bundle pacing superior to biventricular pacing？

OBJECTIVE

To investigate the efficacy and safety of His-bundle pacing (HBP) compared with the traditional biventricular pacing (BVP) on patients with brady-arrhythmias, who suffer from permanent atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF).

METHODS

All patients with brady-arrhythmias, permanent AF and HFrEF were continuously enrolled from January 2017 to July 2019 and followed up for at least 12 months. The differences in QRS duration (QRSd), New York Heart Association (NYHA) classification, left ventricular ejection fraction (LVEF), tricuspid regurgitation grade, mitral regurgitation grade, left ventricular end-diastolic diameter (LVEDD), and left atrial size were compared.

RESULTS

A total of 52 patients were enrolled: 37 patients were with HBP and 15 patients with BVP. There was no electrode dislodged, perforation, infection or thrombosis during the follow-up of 18.12 ± 4.45 months. The success rate for HBP implantation was 88.10%. The capture threshold of his-bundle and the threshold of the left ventricular lead remained stable during follow-up. LVEF increased to higher than 50% in 11 patients with HBP (29.73%). The NYHA classification (both p < .001), LVEF (both p < .001) and LVEDD improved significantly during the follow-up in both groups. NYHA (p = .030), LVEF (p = .013), and LVEDD (p = .003) improved in patients with HBP compared with BVP.

CONCLUSION

HBP was safe and more effective in improving the cardiac function and remodeling in patients with brady-arrhythmias, permanent AF and HFrEF compared with BVP.

Conduction System Pacing for Cardiac Resynchronisation

Conduction system pacing (CSP) is a technique of pacing that involves implantation of permanent pacing leads along different sites of the cardiac conduction system and includes His bundle pacing and left bundle branch pacing. There is an emerging role for CSP to achieve cardiac resynchronisation in patients with heart failure with reduced ejection fraction and inter-ventricular dyssynchrony. In this article, the authors review these strategies for resynchronisation and the available data on the use of CSP in overcoming dyssynchrony.

Effectiveness and safety of AV node ablation after His bundle pacing in patients with uncontrolled atrial arrhythmias

INTRODUCTION

In patients with uncontrolled atrial fibrillation, atrioventricular (AV) node ablation after permanent His bundle pacing (p-HBP) could be a therapeutic option for heart rate (HR) control. We aimed to demonstrate the advantages of AV node ablation with p-HBP, and to describe its effectiveness and safety.

METHODS

This descriptive observational study included patients with uncontrolled permanent atrial arrhythmias who were candidates for HR control (January 2019 to July 2020) and underwent p-HBP and AV node ablation.

RESULTS

A total of 39 patients were included. The median left ventricular ejection fraction (LVEF) was 55% (45-60); 46.1% in NYHA class II and 43.6% in NYHA class III. p-HBP was achieved in 92.3% (n = 36), and AV node ablation was successfully performed in all patients. The LVEF improved in patients with reduced LVEF (baseline, 35% [23.8-45.3%]; follow-up, 40% [35-56.5%], p < 0.05); the NYHA class also showed improvement (baseline, 71.4% patients in class III and 7.1% in class II, and at follow-up, 78.6% patients in class II and 14.3% in class I). In patients with previously normal LVEF, LVEF remained stable; nevertheless, a significant NYHA class improvement was observed (baseline, 63.6% class II and 31.8% class III patients; follow-up, 54.5% class I and 45.5% class II patients). The His thresholds and lead parameter values did not significantly change during the follow-up and remained stable.

CONCLUSIONS

In patients with uncontrolled atrial arrhythmias who underwent AV node ablation after p-HBP, the NYHA class improved and the LVEF increased in those with reduced baseline LVEF. The values of pacing parameters were acceptable and remained stable during the follow-up.

Left Bundle Branch Pacing: Current Knowledge and Future Prospects

Cardiac pacing is an effective therapy for treating patients with bradycardia due to sinus node dysfunction or atrioventricular block. However, traditional right ventricular apical pacing (RVAP) causes electric and mechanical dyssynchrony, which is associated with increased risk for atrial arrhythmias and heart failure. Therefore, there is a need to develop a physiological pacing approach that activates the normal cardiac conduction and provides synchronized contraction of ventricles. Although His bundle pacing (HBP) has been widely used as a physiological pacing modality, it is limited by challenging implantation technique, unsatisfactory success rate in patients with wide QRS wave, high pacing capture threshold, and early battery depletion. Recently, the left bundle branch pacing (LBBP), defined as the capture of left bundle branch (LBB) via transventricular septal approach, has emerged as a newly physiological pacing modality. Results from early clinical studies have demonstrated LBBP's feasibility and safety, with rare complications and high success rate. Overall, this approach has been found to provide physiological pacing that guarantees electrical synchrony of the left ventricle with low pacing threshold. This was previously specifically characterized by narrow paced QRS duration, large R waves, fast synchronized left ventricular activation, and correction of left bundle branch block. Therefore, LBBP may be a potential alternative pacing modality for both RVAP and cardiac resynchronization therapy with HBP or biventricular pacing (BVP). However, the technique's widespread adaptation needs further validation to ascertain its safety and efficacy in randomized clinical trials. In this review, we discuss the current knowledge of LBBP.

Long-Term Safety and Feasibility of Left Bundle Branch Pacing in a Large Single-Center Study

BACKGROUND

Left bundle branch pacing (LBBP) is a novel pacing method and has been observed to have low and stable pacing thresholds in prior small short-term studies. The objective of this study was to evaluate the feasibility and safety of LBBP in a large consecutive diverse group of patients with long-term follow-up.

METHODS

This study prospectively enrolled 632 consecutive pacemaker patients with attempted LBBP from April 2017 to July 2019. Pacing parameters, complications, ECG, and echocardiographic measurements were assessed at implant and during follow-up of 1, 6, 12, and 24 months.

RESULTS

LBBP was successful in 618/632 (97.8%) patients according to strict criteria for LBB capture. Mean follow-up time was 18.6±6.7 months. Two hundred thirty-one patients had follow-up over 2 years. LBB capture threshold at implant was 0.65±0.27 mV at 0.5 ms and 0.69±0.24 mV at 0.5 ms at 2-year follow-up. A significant decrease in QRS duration was observed in patients with left bundle branch block (167.22±18.99 versus 124.02±24.15 ms, P<0.001). Postimplantation left ventricular ejection fraction improved in patients with QRS≥120 ms (48.82±17.78% versus 58.12±13.04%, P<0.001). The number of patients with moderate and severe tricuspid regurgitation decreased at 1 year. Permanent right bundle branch injury occurred in 55 (8.9%) patients. LBB capture threshold increased to >3 V or loss of bundle capture in 6 patients (1%), 2 patients of them had a loss of conduction system capture. Two patients required lead revision due to dislodgement.

CONCLUSIONS

This large observational study suggests that LBBP is feasible with high success rates and low complication rates during long-term follow-up. Therefore, LBBP appears to be a reliable method for physiological pacing for patients with either a bradycardia or heart failure pacing indication.

Long-term outcomes after radiofrequency catheter ablation of the atrioventricular node: The experience of a Portuguese tertiary center

INTRODUCTION

In patients with supraventricular arrhythmias and high ventricular rate, unresponsive to rate and rhythm control therapy or catheter ablation, atrioventricular (AV) node ablation may be performed.

OBJECTIVES

To assess long-term outcomes after AV node ablation and to analyze predictors of adverse events.

METHODS

We performed a detailed retrospective analysis of all patients who underwent AV node ablation between February 1997 and February 2019, in a single Portuguese tertiary center.

RESULTS

A total of 123 patients, mean age 69±9 years and 52% male, underwent AV node ablation. Most of them presented atrial fibrillation at baseline (65%). During a median follow-up of 8.5 years (interquartile range 3.8-11.8), patients improved heart failure (HF) functional class (NYHA class III-IV 46% versus 13%, p=0.001), and there were reductions in hospitalizations due to HF (0.98±1.3 versus 0.28±0.8, p=0.001) and emergency department (ED) visits (1.1±1 versus 0.17±0.7, p=0.0001). There were no device-related complications. Despite permanent pacemaker stimulation, left ventricular ejection fraction did not worsen (47±13% vs. 47%±12, p=0.63). Twenty-eight patients died (23%). The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome (OR 1.8, 95% CI 1.24-2.61, p=0.002).

CONCLUSIONS

Despite pacemaker dependency, the clinical benefit of AV node ablation persisted at long-term follow-up. The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome. AV node ablation should probably be considered earlier in the treatment of patients with supraventricular arrhythmias and HF, especially in cases that are unsuitable for selective ablation of the specific arrhythmia.

Effects of Rhythm and Rate-Controlling Drugs in Patients With Permanent His-Bundle Pacing

Introduction: Antiarrhythmic drug therapy can affect pacemaker parameters in both the atrial and ventricular myocardium. It is not known whether antiarrhythmic drugs impact His bundle pacing/sensing parameters and His to ventricle (H-V) intervals following permanent His bundle pacing (HBP). The aims of the study were to prospectively determine the influence of rhythm and rate-controlling drugs on pacing parameters and H-V conduction after His bundle lead implantation and to assess the impact of rhythm and rate-controlling drugs on the safety of HBP.

Materials and Methods: Patients (N = 140) with QRS duration < 120 ms who met permanent pacing indications were prospectively enrolled. Propafenone, lidocaine, and adenosine were injected intravenously after implantation of 3,830 lead during the procedure. Metoprolol succinate, amiodarone, and digoxin were taken orally for 1 month. Pacing parameters before and after drug intervention was measured, including His capture threshold, sensing and impedance, H-V interval, and conduction.

Results: There were no statistically significant differences in His bundle pacing thresholds, impedance, and sensing after drug intervention at implantation or during a 2-month follow-up (P > 0.05). The HV interval was not affected except in the large-dose propafenone group where HV interval prolonged (P = 0.001). All patients maintained 1:1 H-V conduction following drug administration.

Conclusion: There was no adverse impact on the HBP parameters or H-V conduction after the administration of commonly used dosage of rhythm and rate-controlling drugs. The drugs were safe in patients with permanent His bundle pacing.

Novel left ventricular cardiac synchronization: left ventricular septal pacing or left bundle branch pacing?

It is well recognized that a high burden of right ventricular pacing results in deleterious clinical outcomes over the long term. His bundle pacing can achieve optimal ventricular synchronization; however, relatively high pacing thresholds, low R-wave amplitudes, and the long-term performance have been concerns. Recently, left ventricular (LV) septal endocardium pacing (LVSP) has demonstrated improved acute haemodynamics. Another novel technique of intraseptal left bundle branch pacing (LBBP) via transvenous approach has been adopted rapidly and has demonstrated its feasibility and effectiveness. This article reviews the clinical application and differences between LVSP and LBBP. Compared with LVSP, LBBP has strict criteria for left conduction system capture and lead location. In addition to LV septal capture it also stimulates the proximal left bundle branch, resulting in rapid and physiological LV activation. With a uniformity and standardization of the implant procedure and definitions, it may be possible to achieve widespread application of this form of physiological pacing.

Cardiac resynchronization therapy in heart failure patients: tough road but clear future

Cardiac resynchronization therapy (CRT) based on biventricular pacing (BVP) is an invaluable intervention currently used in heart failure (HF) patients. The therapy involves electromechanical dyssynchrony, which can not only improve heart function and quality of life but also reduce hospitalization and mortality rates. However, approximately 30% to 40% of patients remain unresponsive to conventional BVP in clinical practice. In the recent years, extensive research has been employed to find a more physiological approach to cardiac resynchronization. The His-Purkinje system pacing (HPSP) including His bundle pacing (HBP) and left bundle branch area pacing (LBBaP) may potentially be the future of CRT. These technologies present various advantages including offering an almost real physiological pacing, less complicated procedures, and economic feasibility. Additionally, other methods, such as isolated left-ventricular pacing and multipoint pacing, may in the future be important but non-mainstream alternatives to CRT because currently, there is no strong evidence to support their effectiveness. This article reviews the current situation and latest progress in CRT, explores the existing technology, and highlights future prospects in the development of CRT.

The Emerging Role of Cardiac Conduction System Pacing as a Treatment for Heart Failure

PURPOSE OF REVIEW

The aim of cardiac resynchronization therapy (CRT) is to improve cardiac function by delivering more physiological cardiac activation to patients with heart failure and conduction abnormalities. Biventricular pacing (BVP) is the most commonly used method for delivering CRT; it has been shown in large randomized controlled trials to significantly improve morbidity and mortality in patients with heart failure. However, BVP delivers only modest reductions in ventricular activation time and is only beneficial in patients with prolonged QRS duration. In this review, we explore conduction system pacing as a method for delivering more effective ventricular resynchronization and to extend pacing therapy for heart failure to patients without left bundle branch block (LBBB).

RECENT FINDINGS

The aim of conduction system pacing is to provide physiological ventricular activation by directly stimulating the conduction system. Current modalities include His bundle and left conduction system pacing. His bundle pacing is the most established method; it has the potential to correct left bundle branch block and deliver more effective ventricular resynchronization than BVP. This translates into greater acute haemodynamic improvements and observational data suggests that His-CRT results in improvements in cardiac function and symptoms. AV-optimized His bundle pacing is being investigated in patients with heart failure and long PR interval without LBBB, to see if this improves exercise capacity. More recently, a technique for pacing the left bundle branch has been developed. Early studies show potential advantages including low and stable capture thresholds. Conduction system pacing can deliver more effective ventricular resynchronization than BVP, which has the potential to deliver greater improvements in cardiac function. It may also provide the opportunity to extend pacing therapy for heart failure to patients who do not have LBBB. Further data is required from randomized trials to assess these promising pacing techniques.

High efficiency and workflow of His bundle pacing and atrioventricular node ablation guided by three-dimensional mapping system

BACKGROUND

Atrioventricular node (AVN) ablation combined with His bundle pacing is an effective strategy for permanent atrial fibrillation (AF) with rapid ventricular rate refractory to pharmacological therapy. We aimed to access the feasibility and efficiency of His bundle pacing and AVN ablation guided by three-dimensional (3-D) mapping system throughout the procedure.

METHODS

Eighteen patients with permanent AF with refractory rate and symptoms were referred for His bundle pacing and AVN ablation guided by 3-D mapping (CARTO3). Electroanatomic 3-D mapping of the right atrium and right ventricle was performed by the ablation catheter with CARTO 3 system, followed by the visualization of the leads for implantation and AVN ablation.

RESULTS

Implantation of His bundle and ventricular leads and AVN ablation were achieved successfully with the help of 3-D mapping in 17 patients. Selective His bundle pacing was achieved in five patients (29.4%), and the other (70.6%) were nonselective His bundle pacing. The mean procedure duration was 99.4 ± 16.4 minutes. The mean fluoroscopy time was 7.0 ± 2.6 minutes. The time spent on His lead implantation was 6.1 ± 3.2 minutes. One patient experienced AVN ablation from left side under aortic valves due to no effect of ablation in right atrium.

CONCLUSION

His bundle pacing and AVN ablation guided by throughout real-time 3-D mapping system are of high-efficiency and feasibility.

Clinical outcomes of His-Purkinje conduction system pacing

His-Purkinje conduction system pacing (HPCSP) in the form of His bundle pacing (HBP) and left bundle branch pacing (LBBP) allows normal left ventricular activation, thereby preventing the adverse consequences of right ventricular pacing. HBP has been established for several years with centers from China, Europe, and North America reporting their experience. There is international guidance as to how to implant such systems with the differing patterns of His bundle capture clearly described. LBBP is a more recent innovation with potential advantages including improved pacing parameters. HPCSP has been extensively studied in a variety of indications including cardiac resynchronization therapy, atrioventricular node ablation, and bradycardia pacing. This review will focus on the clinical outcomes of HPCSP including mortality and morbidity of heart failure hospitalization and symptoms.

Permanent left bundle branch area pacing utilizing intracardiac echocardiogram

Background

Recently, left bundle branch area pacing (LBBAP) has been shown to be feasible. However, the right ventricular (RV) implantation site for LBBAP remains elusive. We believe that the RV implantation site should be located at the posteromedial basal septum, and in this paper, we propose a new method to help guide lead implantation. The aim of this study is to demonstrate the feasibility of the proposed method.

Methods

The RV implantation site was positioned by a combination of a nine-grid system on fluoroscopy and the use of intracardiac echocardiogram (ICE) and then verified by ICE.

Results

Fifteen patients were enrolled for LBBAP using our method. The acute success rate was 86.7% (13/15), which demonstrated that our method is useful for assisting with lead implantation. According to ICE, the distance between the implantation site and apex (the front) and the distance between the implantation site and tricuspid annulus (the back) were 44.9 ± 10.7 and 33.2 ± 10.4 mm, respectively, and the ratio of the front and the back was 1.57 ± 0.80. The distance between the implantation site and the front junction point of the left-right ventricle (the upper) and the distance between the implantation site and the back junction point (the lower) were 33.4 ± 10.6 and 24.5 ± 10.2 mm, respectively. The ratio of the upper to the lower was 1.76 ± 1.36. These results suggest that the implantation site was at the posteromedial basal septum. The width of the QRS duration increased from 110.4 ± 33.1 ms at baseline to 114.1 ± 16.1 ms post LBBAP (P > 0.05). The operation time was 133 ± 32.9 min. The time of X-ray fluoroscopy was 21.2 ± 5.9 min. The mean time for lead positioning during LBBAP was 33.8 ± 16.6 min. During a follow-up of 3 months, the LBB capture threshold remained stable in 12 patients, except for one patient who had an increase in the LBB capture threshold to 3.0 v/0.4 ms.

Conclusions

Our preliminary results indicate that the posteromedial basal septum could be seen as the implantation site for LBBAP. As a technique for LBBAP, ICE is a useful method for assisting with lead implantation. It is feasible and safe to use a nine-grid system combined with ICE for LBBAP.

His bundle pacing for cardiac resynchronization therapy: a systematic literature review and meta-analysis

BACKGROUND

Permanent His bundle pacing has been to shown to be an alternative for the patients with CRT indications and more recently has been evaluated for feasibility as a first-line strategy. Data on His bundle pacing (HBP) for cardiac resynchronization therapy are largely limited to small single-center reports, and clinical benefits and risks have not been systematically examined. The purpose of this study was to systematically review published studies of HBP for cardiac resynchronization therapy and evaluate the feasibility and efficacy of the therapy.

METHODS

PubMed, Cochrane Library, Embase, CNKI, and WANFANG databases were searched up to December 2019 to identify relevant studies. Clinical outcomes of interest include implant success rate; Q wave, R wave, and S wave QRS duration; pacing thresholds; left ventricular ejection fraction (LVEF); left ventricular end-diastolic dimension (LVEDD); and New York Heart Association (NYHA) status, complications, and mortality. Extract and summarize the data. Using Revman5.3 software to perform the meta-analysis.

RESULTS

A total of 13 studies involving 503 patients were included. The average implant success rate was 79.8% (95% CI 72.4-87.2%). Permanent HBP resulted in a significant narrow of mean QRS duration from 165.5 ± 8.7 to 122.9 ± 12.0 ms (MD = 43.5, 95%Cl: 36.34 ~ 50.56, p < 0.001). A trend of increase was observed in capture thresholds at follow-up compared with that in the baseline threshold (MD = - 0.24, 95% Cl: - 0.38 ~ - 0.10, p = 0.001). Average NYHA functional class (MD = 1.2, 95% CI: 1.09 ~ 1.31, p < 0.001), LVEF (MD = - 12.60, 95% Cl: - 14.32 ~ - 10.87, p < 0.001), LVEDD (MD = 4.30, 95% Cl: 3.05 ~ 5.55, p < 0.001) significantly improved at > 3 months follow-up compared with that of the baseline (p < 0.001). Ten studies reported safety information and the most commonly reported complication was the increase in HB capture threshold.

CONCLUSIONS

HBP is feasible with a reasonable success rate in patients requiring CRT. HBP could achieve significant narrow of QRS duration and improve left ventricular function during follow-up. Randomized controlled trials are needed to further assess the efficacy of HBP compared with that of biventricular pacing (BVP) in achieving CRT. Graphical abstract Schematic representation of detecting ofloxacin (OFL) by differential pulse voltammetry approach based on the laser modified glassy carbon electrode (LGCE), which increased the active functional groups and surface area compared to GCE.

The efficacy of left bundle branch area pacing compared with biventricular pacing in patients with heart failure: A matched case-control study

BACKGROUND

Left bundle branch area pacing (LBBAP) was reported to improve cardiac function by correcting complete left bundle branch block (CLBBB). Our study aimed to compare the efficacy of LBBAP and biventricular pacing (BIVP) in heart failure patients with CLBBB.

METHODS

Ten patients prospectively underwent LBBAP (LBB-CRT group) and 30 patients received BIVP (BIV-CRT group) were matched using propensity score matching. LBBAP was achieved by the trans-interventricular septum method. Echocardiography, electrocardiogram, NYHA classification, and blood B-type natriuretic peptide concentration were evaluated at preimplantation and at 6-month follow up. CRT response was defined as at least 15% decrease in left ventricular end-systolic volume.

RESULTS

In the LBB-CRT group, CLBBB were successfully corrected by LBBAP with no complications. QRS duration (QRSd) significantly decreased after implantation in both groups, and the decrease of QRSd in the LBB-CRT group was significantly greater than that in the BIV-CRT group (60.80 ± 20.09 vs. 33.00 ± 21.48 ms, p = .0009). The echocardiographic measurements including left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left ventricular ejection fraction significantly improved after 6 months in both groups. The response rate was significantly higher in LBB-CRT group than BIV-CRT group (100.00% vs. 63.33%, p = .038). The percentage of patients in New York Heart Association classification Grades I and II was significantly higher in the LBB-CRT group compared with that in the BIV-CRT group (median 1.5 vs. 2.0, p = .029) at 6-month follow-up.

CONCLUSIONS

It is effective and safe to correct CLBBB with LBBAP in heart failure patients. Compared with BIVP, LBBAP can better optimize electrical synchrony and improve cardiac function.

Mid-term feasibility, safety and outcomes of left bundle branch pacing-single center experience

BACKGROUND

His bundle pacing (HBP) has evolved as the most physiological form of pacing but associated with limitations. Recently, left bundle branch pacing (LBBP) is emerging as an effective alternative strategy for HBP.

OBJECTIVES

Our study was designed to assess the feasibility, efficacy, electrophysiological parameters, and mid-term outcomes of LBBP in Indian population.

METHODS

All patients requiring permanent pacemaker implantation for symptomatic bradycardia and heart failure were prospectively enrolled. Echocardiography, QRS duration, pacing parameters, left bundle (LB) potentials, paced QRS duration, and peak left ventricular activation time (pLVAT) were recorded.

RESULTS

LBBP was successful in 93 out of 99 patients (94% acute success). Mean age was 62.6 ± 13 years, male 59%, diabetes 69%, and coronary artery disease 65%. Follow-up duration was 4.8 months (range1-12 months). Indication for pacing included atrioventricular (AV) block 43%, cardiac resynchronization therapy 44%, and AV node ablation 4%. LB potential was noted in 37 patients (40%). QRS duration reduced from 144.38 ± 34.6 at baseline to 110.8 ± 12.4 ms after LBBP (p < 0.0001). Pacing threshold was 0.59 ± 0.22 V and sensed R wave 14.14 ± 7.19 mV, and it remained stable during follow-up. Lead depth in the septum was 9.62 mm. LV ejection fraction increased from 44.96 to 53.3% after LBBP (p < 0.0001). One died due to respiratory tract infection on follow up.

CONCLUSION

LBBP is a safe and effective strategy (94% acute success) of physiological pacing. The pacing parameters remained stable over a period of 12 months follow-up. LBBP can effectively overcome the limitations of HBP.

His-Purkinje conduction system pacing and atrioventricular node ablation

His-Purkinje conduction system pacing (HPCSP) in the form of His bundle pacing and left bundle branch pacing allows normal ventricular activation, thereby preventing the adverse consequences of right ventricular pacing. One potential area where HPCSP could be used is in the field of atrioventricular (AV) node ablation in patients with atrial fibrillation refractory to medical therapy and/or catheter ablation. His bundle pacing has been established for several years, with centres from North America, Europe and China publishing their experience. The differing patterns of His bundle capture are clearly described with established guidance as to how to implant such systems. Left bundle branch pacing has only recently been reported, but there are several advantages with better pacing parameters and lower risk of threshold change after AV node ablation. Six studies have been identified in the literature which describe the experience of His bundle pacing in patients requiring AV node ablation. Overall the results are positive and favour this new technique; however, they are limited by low numbers of patients and non-randomised study design. An observational study was recently published demonstrating better outcomes with left bundle branch pacing in a small number of patients with left ventricular dysfunction and atrial fibrillation that underwent AV node ablation. HPCSP has the potential to be the primary pacing modality in patients with atrial fibrillation requiring AV node ablation. However, it is essential that this is confirmed in large randomised clinical trials.