His Bundle Pacing In Patients Research Articles

Approach to Left Bundle Branch Pacing.

Cardiac pacing refers to the implantation tool serving as a treatment modality for various indications, the most common of which is symptomatic bradyarrhythmia. Left bundle branch pacing has been noted in the literature to be safer than biventricular pacing or His-bundle pacing in patients with left bundle branch block (LBBB) and heart failure, thereby becoming the focus of further research on cardiac pacing. A review of the literature was conducted using a combination of keywords, including "Left Bundle Branch Block," "Procedural techniques," "Left Bundle Capture," and "Complications." The following factors have been investigated as key criteria for direct capture: paced QRS morphology, peak left ventricular activation time, left bundle potential, nonselective and selective left bundle capture, and programmed deep septal stimulation protocol. In addition, complications of LBBP, inclusive of septal perforation, thromboembolism, right bundle branch injury, septal artery injury, lead dislodgement, lead fracture, and lead extraction, have also been elaborated on. Despite clinical implications based on clinical research comparing the use of LBBP with other forms such as right ventricular apex pacing, His-bundle pacing, biventricular pacing, and left ventricular septal pacing, a paucity in the literature on long-term effects and efficacy has been noted. LBBP can thus be considered to have a promising future in patients requiring cardiac pacing, assuming that additional research on clinical outcomes and the limitation of significant complications such as thromboembolism can be established.

Long-term follow-up of selective and non-selective His bundle pacing leads in patients with atrioventricular block.

His bundle pacing (HBP) is a novel treatment with limited knowledge on long-term outcome. We aimed to assess long-term safety and effectiveness of HBP in patients with atrioventricular block treated with HBP and a back-up right ventricular pacing (RVP) lead. We included 38 patients from a completed single-center, randomized controlled cross-over trial designed to compare left ventricular (LV) function after 12months of HBP vs. RVP conducted between September 2007 and August 2011. Lead performance beyond the 2-year study period was assessed based on a retrospective review of capture thresholds, sensing, impedance, energy consumption, and rate of HBP interruption. Patients were followed for a mean of 7 ± 4years. Both at baseline and during follow-up, HBP leads displayed significantly higher capture thresholds than RVP leads (P < 0.001), multifold higher energy consumption (P < 0.001), and lower sensing amplitudes (P < 0.001). During follow-up, 17 (53%) HBP leads were deactivated or abandoned. The principal cause for HBP interruption was high pacing thresholds in patients with preserved LVEF during RVP. Device longevity was shorter than that of contemporary cohorts treated with dual-chamber pacing or CRT, and time to first device exchange was 6.8 ± 1.5years. No lead dislodgements occurred, but four patients (10%) developed device-related infections requiring device extraction. HBP was interrupted in > 50% of patients during long-term follow-up. The principal cause was unacceptably high capture thresholds and no significant difference in LV function with HBP compared with RVP. Device longevity was shorter, and infection rates were higher than anticipated.

The success rate of His-Purkinje system pacing in patients with various sites of atrioventricular block

Objective: To evaluate the success rate of His-Purkinje system pacing (HPSP) in patients with various sites of atrioventricular block (AVB) and provide clinical evidence for the selection of HPSP in patients with AVB. Methods: This is a retrospective case analysis. 637 patients with AVB who underwent permanent cardiac pacemaker implantation and requiring high proportion of ventricular pacing from March 2016 to September 2021 in the Department of Cardiology, General Hospital of Northern Theater Command were enrolled. The site of AVB was determined by electrophysiological examination. His bundle pacing (HBP) was performed in the first 130 patients (20.4%) who were classified as the HBP group and HPSP included HBP and/or left bundle branch pacing (LBBP) was performed in later 507 patients (79.6%) and these patients were classified as the HPSP group. The basic clinical information such as age and sex of the two groups was compared, and the success rates of HBP or HPSP in patients with different sites of AVB and QRS intervals were analyzed. Results: The age of HBP group was (66.4±15.9) years with 75 males (57.7%). The age of HPSP group was (66.8±13.6) years with 288 (56.8%) males. Among 637 patients, 63.0% (401/637) had atrioventricular node block; 22.9% (146/637) had intra-His block; 14.1% (90/637) had distal or inferior His bundle block. Totally, the success rate of HPSP was higher than that of HBP [93.9% (476/507) vs. 86.9% (113/130), P<0.05]. In each group of patients with various AVB sites, the success rate of HPSP was higher than that of HBP respectively and both success rates of HBP and HPSP showed a declining trend with the distant AVB site. The success rate of HBP in patients with atrioventricular node block and intra-His block was higher than that in patients with distal or inferior His bundle block [95.2% (79/83) vs. 47.1% (8/17), P<0.001; 86.7% (26/30) vs. 47.1% (8/17), P=0.010]. The success rate of HPSP was higher than that of HBP in patients with distal or inferior His bundle block [87.7% (64/73) vs 47.1% (8/17), P=0.001]. In patients with QRS<120 ms, 94.9% (520/548) of AVB sites were in atrioventricular node or intra-His, and HBP had a similar high success rate with HPSP [95.6% (109/114) vs. 96.3% (418/434), P=0.943] in these patients. In patients with QRS ≥ 120 ms, 69.7% (62/89) of AVB sites were at distal or inferior His bundle, and the success rate of HBP was only 25.0% (4/16), while the success rate of HPSP was as high as 79.5% (58/73), P<0.001. Conclusions: In patients with QRS<120 ms and atrioventricular node block or intra-His block, success rates of HBP and HPSP are similarly high and HBP might be considered as the first choice. In patients with QRS ≥ 120 ms and AVB site at distal or inferior His bundle, the success rate of HPSP is higher than that of HBP, suggesting LBBP should be considered as the first-line treatment option.

Short term outcome of distal (ventricular) His bundle pacing and atrioventricular node ablation in patients with symptomatic atrial fibrillation - Refining the concept

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Many patients with atrial fibrillation (AF) do not benefit from rhythm control due to failed catheter ablation, advanced left atrial disease and comorbidities. "Pace and AV node (AVN) ablation" strategy is often adopted for rate control but with a substantial risk of pacing-induced cardiomyopathy. His bundle pacing (HBP) enables physiological biventricular activation through the His Purkinje conduction system. However, the proximity of the HBP lead to the site of AV node ablation may potentially compromise lead integrity in patients who undergo conventional HBP and AVN ablation. Therefore, we have modified HBP by placing the HBP lead distally at the ventricular side of the His bundle (D-HBP) before AVN ablation in patients with symptomatic AF. All patients had a backup RV lead. Method Patients who had D-HBP as part of a "Pace and AVN ablation" strategy were retrospectively analysed. Implant and device clinic follow-up data were collected and analysed. Result Twenty-one patients who had "pace and AVN ablation strategy" with D-HBP between 26th February 2020 and 3rd November 2021 were included. They had a mean age of 75 ± 1.4 years (mean ± SEM), NYHA class of 2.1 ± 0.2, QRS duration of 106 ± 5.3ms and 50% had at least moderately impaired LV systolic function. Seventeen patients (81%) had narrow QRS duration. D-HBP was successful in twenty of twenty-one patients (95%). At D-HBP implant, the mean acute threshold of the HBP lead was 0.96 ± 0.12V at 0.5 ± 0.05ms and the mean HBP lead impedance was 548.1 ± 29.5Ω. Selective HBP pacing was observed in thirteen of twenty patients. The mean QRS duration of HBP paced beats was 104.5 ± 4.7ms. Failure to capture the His bundle was observed in one patient. AVN ablation was performed on the same day after D-HBP in eleven patients and as a subsequent procedure in nine patients. The mean duration of procedure and fluoroscopy for D-HBP were 77.4 ± 4.6 minutes and 11.9 ± 1.4 minutes respectively. There were no acute procedural complications with no lead damage, displacement or lead perforation observed. The median follow-up period was 207 days. The mean D-HBP lead threshold following AVN ablation was 1.1 ± 0.2 V at 0.6 ± 0.07 ms and the mean lead impedance was 433.8 ± 20.7Ω, which were similar to before AVN ablation. One patient was reprogrammed with RV pacing only for elevated HBP lead threshold after AVN ablation to 4.2 V at 1ms. The mean D-HBP percentage was 92.3 ± 6.6% and the mean estimated battery longevity of the pacemaker was 7.9 ± 0.6 years at the last follow up. There was improvement in heart failure symptoms in eight patients from previously symptomatic to NYHA class I following D-HBP and AVN ablation. Conclusion D-HBP appear to be safe with potentially more favourable lead parameters than conventional proximal HBP in patients with symptomatic AF offered "Pace and AVN ablation" strategy.

Conduction system pacing following septal myectomy: Insights into site of conduction block.

Septal myectomy for obstructive hypertrophic cardiomyopathy (HCM) is associated with conduction block; however, the electrophysiological characteristics of conduction block have not been well characterized. The aim of study was to assess the feasibility and safety of His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) in patients with septal myectomy-associated conduction block. Patients with HCM and indications for pacing or cardiac resynchronization therapy after septal myectomy were included. Electrophysiological mapping was performed to identify the site of block. The success rates and pacing characteristics of HBP and LBBAP were also recorded. The echocardiographic data and complications were documented and tracked during follow-up. Ten patients with atrioventricular block (AVB) or left bundle branch block (LBBB) post-myectomy were included in the study. The site of block was infranodal in the nine patients with AVB. HBP failed due to the lack of distal His bundle capture (N = 7) or LBBB correction (N = 3). LBBAP was successful in nine patients and failed in one. QRS duration narrowed from 163.3 ± 16.6 ms after surgery to 123.6 ± 15.8 ms during LBBAP (p < .001). The mean depth of the leads was 13.3 ± 4.0 mm (range from 10 to 20 mm). At a mean follow-up of 5.3 ± 3.9 months, pacing parameters and left ventricular ejection fraction remained stable. Electrophysiological mapping revealed that the site of block was infra-Hisian and not correctable with HBP in patients with HCM post-myectomy. LBBAP appears to be a more feasible physiological strategy for these patients.

B-PO03-023 HIS BUNDLE PACING ACHIEVES BETTER VENTRICULAR SYNCHRONY THAN BIVENTRICULAR PACING IN PATIENTS WITH SCAR IN THE LEFT VENTRICULAR FREE WALL

His bundle pacing (HBP) is a novel pacing strategy for cardiac resynchronization therapy (CRT). HBP has been associated with improved response compared to conventional CRT and biventricular endocardial (BIV-endo) pacing. The effect of HBP in patients with scar has however not yet been studied. To investigate differences in response between HBP and BIV-endo pacing in patients with scar in the left ventricular (LV) free wall. We computed ventricular activation on 24 four-chamber heart meshes with Purkinje networks exhibiting left bundle branch block (LBBB). We mapped a LV free wall scar and border zone geometry from a pre-existing LV mesh [Fig A]. HBP and BIV-endo pacing were simulated in the presence and in the absence of scar. Response from baseline was quantified with LV 95% activation time (LV-AT 95) and biventricular dyssynchronous index (BIV-DI), computed as the standard deviation of ventricular activation times. BIV-DI was significantly reduced during HBP compared to BIV-endo pacing both in the presence (-13±2ms vs -15±2ms, p<0.05) and in the absence (-9±2 ms vs -11±2ms, p<0.05) of scar in the LV lateral wall [Fig B]. LV-AT 95 was also significantly shorter during HBP compared to BIV-endo pacing (scar: -31±8ms vs -54±9ms, p<0.05; no scar: -22±7ms vs -44±7ms, p<0.05) [Fig C]. HBP restores native synchronous activation by recruiting the viable fast-conducting Purkinje system. LBBB patients with lateral scar therefore experience better ventricular resynchronization using HBP compared to BIV-endo pacing.

B-PO02-046 DOUBLE SHEATH-DOUBLE LEAD TECHNIQUE TO OVERCOME DIFFICULT CASES OF HIS BUNDLE LEAD IMPLANTATION

Although His bundle pacing (HBP) can be accomplished in most patients using a single C315His sheath and a single lead (SS-SL) technique, in some patients this approach could be unsuccessful. To develop a double sheath double lead ( DS-DL ) technique to increase success in achieving permanent HBP when facing difficult cases. Single center prospective cohort study that enrolled consecutive patients in whom 3 or more initial HBP attempts using the SS-SL technique have failed in spite of recording and/or capturing the His bundle. Instead of removing the lead from the last inserted site, this lead (L1) was left in place and used as a fixed anatomical radiographic reference. Subsequently, a second Medtronic C315HIS sheath and a second Medtronic SelectSecure™ Model 3830 lead (L2) were introduced to re-initiate the search for a better site around the tip of L1. Depending on the results obtained with L2, either lead can be removed and placed around the tip of other lead (Panels A and B of figure 1). These steps could be repeated in a systematic fashion until achieving adequate thresholds for HBP or declaring the attempts unsuccessful. The lead that was not used for HBP was then placed in the right atrium if indicated (Panel C). The patients had follow-up evaluations at 3, 6, and 12 months post implantation. Eighteen patients were enrolled, mean age 77 ± 10 yrs (10 males). The DS-DL technique was successfully applied to all patients. (See panel D and E of figure 1). This study demonstrated that the DS-DL technique proved to be safe, feasible and highly efficient in achieving permanent HBP in patients in whom the SS-SL technique have failed to achieve a successful implant.

Impact of physiological pacing on functional mitral regurgitation in systolic dysfunction: Initial echocardiographic remodeling findings after His bundle pacing.

BackgroundAlthough His bundle pacing (HBP) has been shown to improve left ventricular ejection fraction (LVEF), its impact on mitral regurgitation (MR) remains uncertain.ObjectivesThe aim of this study was to evaluate change in functional MR after HBP in patients with left ventricular (LV) systolic dysfunction.MethodsPaired echocardiograms were retrospectively assessed in patients with reduced LVEF (<50%) undergoing HBP for pacing or resynchronization. The primary outcomes assessed were change in MR, LVEF, LV volumes, and valve geometry pre- and post-HBP. MR reduction was characterized as a decline in ≥1 MR grade post-HBP in patients with ≥grade 3 MR at baseline.ResultsThirty patients were analyzed: age 68 ± 15 years, 73% male, LVEF 32% ± 10%, 38% coronary artery disease, 33% history of atrial fibrillation. Baseline QRS was 162 ± 31 ms: 33% left bundle branch block, 37% right bundle branch block, 17% paced, and 13% narrow QRS. Significant reductions in LV end-systolic volume (122 mL [73–152 mL] to 89 mL [71–122 mL], P = .006) and increase in LV ejection fraction (31% [25%–37%] to 39% [30%–49%], P < .001) were observed after HBP. Ten patients had grade 3 or 4 MR at baseline, with reduction in MR observed in 7. In patients with at least grade 3 MR at baseline, reduction in LV volumes, improved mitral valve geometry, and greater LV contractility were associated with MR reduction. Greater reduction in paced QRS width was present in MR responders compared to non-MR responders (-40% vs -25%, P = .04).ConclusionsIn this initial detailed echocardiographic analysis in patients with LV systolic dysfunction, HBP reduced functional MR through favorable ventricular remodeling.

Impact of electroanatomical mapping-guided lead implantation on procedural outcome of His bundle pacing.

Conventional His bundle pacing (HBP) can be technically challenging and fluoroscopy-intense, particularly in patients with His-Purkinje conduction disease (HPCD). Three-dimensional electroanatomical mapping (EAM) facilitates non-fluoroscopic lead navigation and HB electrogram mapping. We sought to assess the procedural outcome of routine EAM-guided HBP compared with conventional HBP in a real-world population and evaluate the feasibility and safety of EAM-guided HBP in patients with HPCD. We included 58 consecutive patients (72 ± 13 years; 71% male) who underwent an attempt to conventional (EAM- group; n = 29) or EAM-guided (EAM+ group; n = 29) HBP between June 2019 and April 2020. The centre's learning curve was initially determined (n = 40 cases) to define the conventional control group and minimize outcome bias favouring EAM-guided HBP. His bundle pacing was successful in 26 patients (90%) in the EAM+ and 27 patients (93%) in the EAM- group (P = 0.64). The procedure time was 90 (73-135) and 110 (70-130) min, respectively (P = 0.89). The total fluoroscopy time [0.7 (0.5-1.4) vs. 3.3 (1.4-6.5) min; P < 0.001] and fluoroscopy dose [21.9 (9.1-47.7) vs. 78.6 (27.2-144.9) cGycm2; P = 0.001] were significantly lower in the EAM+ than EAM- group. There were no significant differences between groups in His capture threshold (1.2 ± 0.6 vs. 1.4 ± 1.0 V/1.0 ms; P = 0.33) and paced QRS duration (113 ± 15 vs. 113 ± 17 ms; P = 0.89). In patients with HPCD, paced QRS duration was similar in both groups (121 ± 15 vs. 123 ± 12 ms; P = 0.77). The bundle branch-block recruitment threshold tended to be lower in the EAM+ than EAM- group (1.3 ± 0.7 vs. 1.8 ± 1.2 V/1.0 ms; P = 0.31). No immediate procedure-related complications occurred. One patient (2%) experienced lead dislodgement during 4-week follow-up. Implementation of routine EAM-guided HBP lead implantation is feasible and safe in a real-world cohort of patients with and without HPCD and results in a tremendous reduction in radiation exposure without prolonging procedure time or increasing procedure-related complications.

Upgrade of cardiac resynchronization therapy by utilizing additional His-bundle pacing in patients with inotrope-dependent end-stage heart failure: a case series.

BackgroundHis-bundle pacing (HBP) alone may become an alternative to conventional cardiac resynchronization therapy (CRT) utilizing right ventricular apical (RVA) and left ventricular (LV) pacing (BiVRVA+LV) in selected patients, but the effects of CRT utilizing HBP and LV pacing (BiVHB+LV) on cardiac resynchronization and heart failure (HF) are unclear.Case summaryWe presented two patients with inotrope-dependent end-stage HF in whom the upgrade from conventional BiVRVA+LV to BiVHB+LV pacing by the addition of a lead for HBP improved their HF status. Patient 1 was a 32-year-old man with lamin A/C cardiomyopathy, atrial fibrillation, and complete atrioventricular (AV) block. Patient 2 was a 70-year-old man with ischaemic cardiomyopathy complicated by AV block and worsening of HF resulting from ablation for ventricular tachycardia storm. The HF status of both patients improved dramatically following the upgrade from BiVRVA+LV to BiVHB+LV pacing.DiscussionEnd-stage HF patients suffer from diffuse intraventricular conduction defect not only in the LV but also in the right ventricle (RV). The resulting dyssynchrony may not be sufficiently corrected by conventional BiVRVA+LV pacing or HBP alone. Right ventricular apical pacing itself may also impair RV synchrony. An upgrade to BiVHB+LV pacing could be beneficial in patients who become non-responsive to conventional BiV pacing as the His–Purkinje conduction defect progresses.

Left bundle branch pacing.

Chronic right ventricular (RV) pacing has been associated with significant electrical and mechanical dyssynchrony leading to increased risk for recurrent heart failure hospitalizations and atrial arrhythmias. His bundle pacing (HBP) is an effective alternative to RV pacing as it is physiological and provides synchronized contraction of both ventricles. But there are limitations to HBP, which include lead stability, rise in threshold, early battery depletion and longer learning curve. Huang etal. recently reported anovel technique to directly capture the left bundle branch (LBB) by deep septal pacing. Subsequently, many studies have demonstrated the feasibility, safety and efficacy of left bundle branch pacing (LBBP). This has the potential to overcome the limitations of HBP and provide asafe technique to capture the conduction system in patients with distal His bundle and proximal bundle branch disease. The criteria for LBB capture and the methodology to perform LBBP are discussed in detail in this review. The Medtronic SelectSecure®3830 pacing lead is used along with afixed-curve C315His® or adeflectable C304His® sheath. LBBP providessafe and low threshold compared to HBP. Left bundle potential should be demonstrable in all patients except in those with infrahisian complete heart block (CHB) and complete left bundle branch block (LBBB), wherein antegrade activation of the left bundle will not occur. LBBP has the potential to be an effective alternative to biventricular pacing or HBP in patients with left ventricular dysfunction, LBBB and recurrent heart failure. Long-term safety and clinical outcomes compared to traditional pacing need to be carefully studied in randomized clinical trials.

Keeping pace with the competition: His bundle versus biventricular pacing in heart failure.

His bundle pacing (HBP) has emerged as a novel method to achieve electrical resynchronization in bundle branch block and as an alternative means to deliver cardiac resynchronization therapy (CRT). There are now data on HBP in CRT-eligible patients from cohort studies and a single pilot randomized controlled trial (RCT). Early clinical data regarding HBP in heart failure have demonstrated echocardiographic and functional improvement similar to traditional biventricular pacing (BiV), mostly when utilized as a bailout to traditional BiV-CRT. A single pilot RCT, His-SYNC, showed a trend toward greater echocardiographic response in an on-treatment analysis, but was underpowered. No large RCTs have reported long-term clinical outcomes. In order to realize any benefit from HBP, output-dependent morphology changes must be demonstrated to ensure the conduction system capture is present. There may be a role for corrective HBP in patients with right bundle branch block and after atrioventricular node ablation, which is theoretically more desirable than traditional BiV. Importantly, however, HBP is likely not to benefit patients with nonspecific intraventricular conduction delay. HBP is emerging as an alternative strategy for CRT and may have a role in patients in whom traditional BiV is not achievable or ineffective.

P5426His-bundle pacing in CHF-patients with narrow QRS and chronic AF using dual-chamber ICD - an upgrade from single-chamber to dual-chamber ICD

Abstract A single-chamber ICD is a standard method for primary SCD prophylaxis. In patients with chronic atrial fibrillation it dose not contribute to the regularization of heart rate, which is crucial for proper treatment. The aim of our study was to assess the efficacy of direct His-bundle pacing in patients with congestive heart failure and chronic atrial fibrillation using upgrade from single chamber to dual-chamber ICD. Methods The study population included 21 patients with CHF and chronic AF implanted primarily with single chamber ICD with etablished pharmacotherapy and stable clinical status. Results The echocardiography measurements at baseline and during ollow-up were presented in the table: Table 1 Baseline Follow-up p-value LVEDD (ms) 67.7±10.7 64.5±8.6 &lt;0.05 EF (%) 27.0±4.8 33.2±6.9 &lt;0.05 NYHA class 2.8±0.6 1.9±0,5 &lt;0.05 During short 4-months of follow-up the mean values of EF and LV dimensions significantly improved. This was also accompanied by functional status improvement. Conclusions His-bundle-based pacing in CHF-chronic AF patients contributes to significant echocardiographic and clinical improvement. Standard single-chamber ICD implantation in CHF-chronic AF patients yields only SCD prevention without influence on remodeling process.

P1239His-bundle pacing in CHF-patients with narrow QRS and chronic AF using dual-chamber ICD

Abstract The heart rate regularization is crucial for proper treatment of patients with atrial fibrillation and congestive heart failure. The standard resynchronization can be applied, but in patients with narrow QRS this procedure is of no use. The aim of our study is to assess the efficacy of direct His-bundle pacing in patients with congestive heart failure and chronic atrial fibrillation using dual chamber ICD implanted for prevention of sudden cardiac death. Methods The study population included 78 patients with CHF and chronic AF: group A - 56 pts treated with direct His-bundle pacing using atrial port of dual chamber ICD and group B - 22 patients implanted with single chamber ICD as recommended by the guidelines. The patients in group B constituting clinical controls were derived from the Heart Failure Outpatients Clinic with established clinical status and pharmacotherapy. Results The demographic data, clinical characteristics and echocardiography measurements at baseline and during follow-up were presented in the table: Table 1 Group A Group B P value Age (years) 69.7±6.9 66.7±11.3 n.s. Sex (% of male sex) 84.0 86.4 n.s. Ventricular pacing (%) – 46.3±31.2 – His-bundle pacing (%) 81.7±9.2 – – pre post pre post pre vs. post LVEDD (mm) 66.9±4.9 59.9±4.7 64.8±8.0 64.7±8.1 &lt;0.01 n.s. EF (%) 29.6±3.8 43.6±5.9 28.1±6.1 28.8±7.3 &lt;0.01 n.s. NYHA class 2.7±0.6 1.4±0.6 2.5±0.6 2.0±0.2 &lt;0.05 n.s. B-blocker dose (metoprolol equivalent dose) 104.6±41.6 214.3±82.6 78.3±56.6 103.1±49.2 &lt;0.001 &lt;0.05 During 12-months of follow-up the mean values of NYHA functional class, EF and LV dimensions did not change in group B but significantly improved in group A. The physiological His-bundle based pacing enabled optimal beta-blocker dosing. The studied groups had no tachyarrhythmia at baseline so the presumable atrial fibrillation-related harm depends on the rhythm irregularity. Conclusions His-bundle-based pacing in CHF-chronic AF patients contributes to significant echocardiographic and clinical improvement. Standard single-chamber ICD implantation in CHF-chronic AF patients yields only SCD prevention without influence on remodeling process. The CHF-patients with narrow QRS and chronic AF benefit from substantially higher beta-blockade which can be instituted in His-bundle pacing group.

Outcomes of His-bundle pacing upgrade after long-term right ventricular pacing and/or pacing-induced cardiomyopathy: Insights into disease progression

His-bundle pacing (HBP) is a physiological alternative to right ventricular pacing (RVP). The outcomes of HBP in patients with longstanding atrioventricular block (AVB) and RVP are unknown OBJECTIVE: The purpose of this study was to retrospectively assess the feasibility of HBP in patients with chronic RVP and longstanding AVB and to evaluate its efficacy in reversing the adverse remodeling induced by RVP. HBP was attempted in patients with longstanding AVB and chronic RVP and/or pacing-induced cardiomyopathy (PICM) in need for resynchronization therapy. The site of conduction block and feasibility of HBP was documented. Electrocardiographic and echocardiographic assessments at baseline and follow-up were recorded. HBP was successful in 79 of 85 patients (93%) with RVP for 77.6 ± 74.8 months (range 2-540 months). AV nodal block was present in 59 and infranodal block in 26. QRS duration increased from 123 ± 31 ms at baseline to 177 ± 17 ms (P <.001) during RVP and decreased to 115 ± 20 ms with HBP (P <.001). T-wave memory was observed in 53 of 79 patients with HBP and normalized in 2-12 weeks. HBP threshold was 1.47 ± 0.9 V @ 1 ms at implant and 1.9 ± 1.3 V @ 1 ms at last follow-up (25 ± 24 months). In 60 patients with PICM in whom left ventricular ejection fraction decreased from 54% ± 7.7% at baseline to 34.3% ± 9.6% (P<.001), ejection fraction improved to 48.2% ± 9.8% (P<.001) after HBP CONCLUSION: Despite a long duration of AVB and chronic RVP, HBP normalized QRS complexes and T waves with stable thresholds, suggesting that progression of distal conduction disease is uncommon in this population. Electrical and structural changes induced by chronic RVP were consistently reversed with HBP.

Pacing parameters and success rates of permanent His-bundle pacing in patients with narrow QRS: a single-centre experience.

High and unstable capture thresholds affect the success rate of permanent His-bundle pacing (HBP). We aimed to introduce the modified techniques during different periods and the corresponding success rate of HBP implantation. Patients from a single centre who had intrinsic QRS < 120 ms and HBP attempts were included in the study. The success rate and pacing parameters were described for three periods based on procedural modifications, i.e. Stage 1 using the conventional HBP procedure (August 2012 to May 2013), Stage 2 with addition of the dual-lead method (June 2013 to October 2014), and Stage 3 with the further addition of stability assessment during fixation (November 2014 to October 2016). The patients with successful permanent HBP were followed. A total of 310 patients were included with the average age of 70.3 ± 10.7 years. The success rate of acute HBP was 84.85%, 98.3%, and 99.20% during Stages 1-3, respectively (P < 0.001). The permanent HBP implantation rates increased from 77.3% during Stage 1 to 85.7% during Stage 2 and 89.6% during Stage 3 (P = 0.07). The acute His-bundle capture threshold reduced from 1.30 ± 0.7 V/0.5 ms during Stage 1 to 1.11 ± 0.6 V/0.5 ms during Stage 2 and further to 0.85 ± 0.51 V/0.5 ms during Stage 3 (P < 0.001). At the 12-month follow-up, the mean change in the HBP threshold decreased from 0.60 ± 0.59 V/0.5 ms during Stage 1 to 0.33 ± 0.39 V/0.5 ms during Stage 3 (P = 0.002). The HBP implantation success rate, pacing threshold, and its stability during follow-up were improved by using the dual-lead method and stability assessment techniques.

Permanent His bundle pacing in heart failure patients: A systematic review and meta-analysis.

Cardiac resynchronization therapy (CRT) is the standard-of-care therapy for the patients with heart failure and left ventricular (LV) dyssynchrony. However, approximately 30% of the patients show no response. Recent studies have shown that His bundle pacing (HBP) could be an alternative for the patients with CRT indications. The purpose of this study was to evaluate the efficacy of HBP in patients with heart failure. We searched PubMed and Embase databases for studies evaluating HBP in patients with heart failure and LV dyssynchrony. The successful rate of implantation, QRS duration, pacing threshold, LV function at baseline and follow-up, and mortality rates were extracted and summarized. Eleven studies including 494 patients were included in this analysis. The overall successful rate for implantation was 82.4%. The main indications for HBP were CRT candidates and cardiomyopathy with atrial fibrillation undergoing atrioventricular node ablation. Permanent HBP resulted in narrow QRS duration of 116.3±13.9ms after implantation. LV functions, including echocardiographic parameters and clinical outcomes, significantly improved at follow-up (P<0.001). However, there was a trend of increased capture and bundle branch block correction thresholds at follow-up compared to baseline (P=0.01 and 0.02, respectively). During a mean follow-up of 23.7months, 5.9% of the patients experienced heart failure-related hospitalization and the mortality rate was 9.1%. Permanent HBP has shown promising results for heart failure patients in small observational studies. Randomized controlled trials are needed to assess the efficacy of HBP in these patients.

Permanent His Bundle Pacing for Cardiac Resynchronization Therapy in Patients With Heart Failure and Right Bundle Branch Block.

Background Cardiac resynchronization therapy utilizing biventricular pacing is an effective therapy for patients with left ventricular (LV) systolic dysfunction, left bundle branch block, and heart failure. Benefits of biventricular pacing may be limited in patients with right bundle branch block (RBBB). Permanent His bundle pacing (HBP) has recently been reported as an option for cardiac resynchronization therapy. The aim of the study was to assess the feasibility and outcomes of HBP in patients with RBBB and heart failure. Methods HBP was attempted as a primary or rescue (failed LV lead implant) strategy in patients with reduced LV ejection fraction, RBBB, QRS duration ≥120 ms, and New York Heart Association class II to IV heart failure. Implant characteristics, New York Heart Association functional class, and echocardiographic data were assessed in follow-up. Results Mean age was 72±10 years, female 15%, with an average LV ejection fraction of 31±10%. HBP was successful in 37 of 39 patients (95%) with narrowing of RBBB in 78% cases. His capture and bundle branch block correction thresholds were 1.1±0.6 V and 1.4±0.7 V at 1 ms, respectively. During a mean follow-up of 15±23 months, there was a significant narrowing of QRS from 158±24 to 127±17 ms ( P=0.0001), increase in LV ejection fraction from 31±10% to 39±13% ( P=0.004), and improvement in New York Heart Association functional class from 2.8±0.6 to 2±0.7 ( P=0.0001) with HBP. Increase in capture threshold occurred in 3 patients. Conclusions Permanent HBP was associated with significant narrowing of QRS duration and improvement in LV function in patients with RBBB and reduced LV ejection fraction. Permanent HBP is a promising option for cardiac resynchronization therapy in patients with RBBB and reduced LV ejection fraction.

Atrioventricular node ablation and His bundle pacing.

Atrioventricular node ablation (AVNA) and right ventricular pacing (RVP) are effective therapies for patients with atrial fibrillation (AF) and rapid ventricular rates. His bundle pacing (HBP) is a physiologic alternative to RVP. The aim of our study is to assess the feasibility and safety of HBP in patients undergoing AVNA and its effect on left ventricular (LV) function. Permanent HBP is the preferred form of ventricular pacing at our institute. Atrioventricular node ablation and HBP were performed in patients with AF and difficulty in rate control. His bundle pacing implant characteristics and thresholds were recorded. Fluoroscopic relationship of AVNA site to HBP lead electrodes was documented. Left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) functional class at baseline and during follow-up were assessed. Forty-two patients underwent HBP and AVNA: age 74 ± 11 years; men 45%; HTN 64%; DM 19%; CAD 36%; permanent AF 40%; cardiomyopathy 55%. His bundle pacing was successful in 40 of 42 patients (95%). Successful AVNA site was at or below the ring electrode in 22 (no acute change in HBP threshold); above the ring electrode in 13 and left side in 2 pts (acute increase in HBP threshold in 7 of 15 pts). Final HBP threshold at implant was 1 ± 0.8 V@1 ms and increased to 1.6 ± 1.2 V@1 ms during a mean follow-up of 19 ± 14 months. Left ventricular ejection fraction increased from 43 ± 13% to 50 ± 11% (P = 0.01). New York Heart Association functional status improved from 2.5 ± 0.5 to 1.9 ± 0.5 (P = 0.04). Atrioventricular node ablation and HBP were successful in 95% of patients. His bundle pacing lead characteristics remained relatively stable. Left ventricular ejection fraction improved significantly during follow-up. His bundle pacing is feasible, safe and effective in pts undergoing AVNA.

GW28-e1235 Feasibility and Clinical Outcomes of His Bundle Pacing to Correct Left Bundle Branch Block in Heart Failure Patients

His bundle pacing (HBP) utilizes the His-bundle to achieve synchronous ventricular activation. The study objective was to assess the feasibility of correction of LBBB by HBP and evaluated clinical outcomes of HBP in patients (pts) with heart failure (HF) and LBBB. 57 pts who had LBBB were enrolled