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American Journal of Physiology. Heart... Jan 2021His bundle pacing utilizes the His-Purkinje system to produce more physiological activation compared with traditional pacing therapies, but differences in electrical... (Comparative Study)
Comparative Study
His bundle pacing utilizes the His-Purkinje system to produce more physiological activation compared with traditional pacing therapies, but differences in electrical activation between pacing techniques are not yet quantified in terms of activation pattern. Furthermore, clinicians distinguish between selective and nonselective His pacing, but measurable differences in electrical activation remain to be seen. Hearts isolated from seven dogs were perfused using the Langendorff method. Electrograms were recorded using two 64-electrode basket catheters in the ventricles and a 128-electrode sock situated around the ventricles during sinus rhythm (right atrial pacing), right ventricular (RV) pacing, biventricular cardiac resynchronization therapy (biV-CRT), selective His pacing (selective capture of the His bundle), and nonselective His pacing (capture of nearby myocardium and His bundle). Activation maps were generated from these electrograms. Total activation time (TAT) was measured from the activation maps, and QRS duration was measured from a one-lead pseudo-ECG. Results showed that TAT, QRS duration, and activation sequence were most similar between sinus, selective, and nonselective His pacing. Bland-Altman analyses showed highest levels of similarity between all combinations of sinus, selective, and nonselective His pacing. RV and biV-CRT activation patterns were distinct from sinus and had significantly longer TAT and QRS duration. Cumulative activation graphs were most similar between sinus, selective, and nonselective His pacing. In conclusion, selective pacing and nonselective His bundle pacing are more similar to sinus compared with RV and biV-CRT pacing. Furthermore, selective pacing and nonselective His bundle pacing are not significantly different electrically. Our high-density epicardial and endocardial electrical mapping study demonstrated that selective pacing and nonselective His bundle pacing are more electrically similar to sinus rhythm compared with right ventricular and biventricular cardiac resynchronization therapy pacing. Furthermore, small differences between selective and nonselective His bundle pacing, specifically a wider QRS in nonselective His pacing, do not translate into significant differences in the global activation pattern.
Topics: Action Potentials; Animals; Atrial Function, Right; Bundle of His; Cardiac Pacing, Artificial; Cardiac Resynchronization Therapy Devices; Dogs; Electrophysiologic Techniques, Cardiac; Heart Rate; Isolated Heart Preparation; Male; Purkinje Fibers; Time Factors; Ventricular Function, Left; Ventricular Function, Right
PubMed: 33124884
DOI: 10.1152/ajpheart.00292.2020 -
Cardiology Clinics May 2019Atrial fibrillation (AF) and heart failure (HF) are associated with high morbidity and mortality, which is particularly detrimental when patients develop rapid... (Review)
Review
Atrial fibrillation (AF) and heart failure (HF) are associated with high morbidity and mortality, which is particularly detrimental when patients develop rapid ventricular rates (RVR). Atrioventricular junction (AVJ) ablation with pacemaker implantation has been used as a method of achieving rate control in patients with incessant AF with RVR. Right ventricular only pacing is known to be harmful in the setting of HF. His bundle pacing (HBP) and biventricular (BiV) pacing both offer durable pacing solutions that offer more physiologic activation. This review describes the benefits and drawbacks of HBP and BiV pacing in HF patients after AVJ ablation.
Topics: Atrial Fibrillation; Atrioventricular Node; Bundle of His; Cardiac Pacing, Artificial; Cardiac Resynchronization Therapy; Catheter Ablation; Comorbidity; Global Health; Heart Failure; Heart Rate; Humans; Stroke Volume; Treatment Outcome
PubMed: 30926024
DOI: 10.1016/j.ccl.2019.01.006 -
JACC. Clinical Electrophysiology Jan 2022
Topics: Bundle of His; Bundle-Branch Block; Cardiac Resynchronization Therapy; Humans
PubMed: 35057978
DOI: 10.1016/j.jacep.2021.08.010 -
JACC. Clinical Electrophysiology Nov 2018
Topics: Bundle of His; Cardiac Resynchronization Therapy; Electrophysiology
PubMed: 30466844
DOI: 10.1016/j.jacep.2018.09.006 -
European Journal of Heart Failure Feb 2023Excessive prolongation of PR interval impairs coupling of atrio-ventricular (AV) contraction, which reduces left ventricular pre-load and stroke volume, and worsens... (Randomized Controlled Trial)
Randomized Controlled Trial
Effects of haemodynamically atrio-ventricular optimized His bundle pacing on heart failure symptoms and exercise capacity: the His Optimized Pacing Evaluated for Heart Failure (HOPE-HF) randomized, double-blind, cross-over trial.
AIMS
Excessive prolongation of PR interval impairs coupling of atrio-ventricular (AV) contraction, which reduces left ventricular pre-load and stroke volume, and worsens symptoms. His bundle pacing allows AV delay shortening while maintaining normal ventricular activation. HOPE-HF evaluated whether AV optimized His pacing is preferable to no-pacing, in a double-blind cross-over fashion, in patients with heart failure, left ventricular ejection fraction (LVEF) ≤40%, PR interval ≥200 ms and either QRS ≤140 ms or right bundle branch block.
METHODS AND RESULTS
Patients had atrial and His bundle leads implanted (and an implantable cardioverter-defibrillator lead if clinically indicated) and were randomized to 6 months of pacing and 6 months of no-pacing utilizing a cross-over design. The primary outcome was peak oxygen uptake during symptom-limited exercise. Quality of life, LVEF and patients' holistic symptomatic preference between arms were secondary outcomes. Overall, 167 patients were randomized: 90% men, 69 ± 10 years, QRS duration 124 ± 26 ms, PR interval 249 ± 59 ms, LVEF 33 ± 9%. Neither peak oxygen uptake (+0.25 ml/kg/min, 95% confidence interval [CI] -0.23 to +0.73, p = 0.3) nor LVEF (+0.5%, 95% CI -0.7 to 1.6, p = 0.4) changed with pacing but Minnesota Living with Heart Failure quality of life improved significantly (-3.7, 95% CI -7.1 to -0.3, p = 0.03). Seventy-six percent of patients preferred His bundle pacing-on and 24% pacing-off (p < 0.0001).
CONCLUSION
His bundle pacing did not increase peak oxygen uptake but, under double-blind conditions, significantly improved quality of life and was symptomatically preferred by the clear majority of patients. Ventricular pacing delivered via the His bundle did not adversely impact ventricular function during the 6 months.
Topics: Male; Humans; Female; Bundle of His; Heart Failure; Cross-Over Studies; Stroke Volume; Quality of Life; Exercise Tolerance; Ventricular Function, Left; Oxygen; Treatment Outcome; Cardiac Pacing, Artificial; Cardiac Resynchronization Therapy; Electrocardiography
PubMed: 36404397
DOI: 10.1002/ejhf.2736 -
Pacing and Clinical Electrophysiology :... Sep 2021His bundle pacing (HBP) is a physiological pacing strategy to preserve the electrical synchrony of ventricular conduction and left ventricular (LV) function. Left bundle... (Comparative Study)
Comparative Study
BACKGROUND
His bundle pacing (HBP) is a physiological pacing strategy to preserve the electrical synchrony of ventricular conduction and left ventricular (LV) function. Left bundle branch pacing (LBBP) has emerged as an alternative physiological pacing technique.
OBJECTIVE
To evaluate cardiac electrical and mechanical synchrony comparing LBBP and HBP in patients with permanent atrial fibrillation (AF).
METHODS
Consecutive patients with symptomatic bradycardia and AF were enrolled from January to June of 2019. The cardiac electrical and mechanical synchrony in different pacing mode were evaluated at baseline and after implantation.
RESULTS
Both HBP and LBBP were performed in 20 patients. LBBP significantly widened the QRS duration compared with the intrinsic conduction (113.2 ± 14.5 vs. 96.5 ± 16.2 ms; p = .01), while HBP did not (104.5 ± 22.3 vs. 96.5 ± 16.2 ms; p = .12). Both LBBP and HBP patients had similar LV myocardial strain measurements for the mechanical synchrony evaluation without significant change compared with baseline. There was no significant difference in right ventricular synchrony measurement between LBBP and HBP. Compared to HBP, LBBP had less interventricular synchrony (IMVD, 14.7 ± 9.2 vs. 3.1 ± 12.7 ms, p < .01; Ts-LV-RV, 37.9 ± 10.7 vs. 18.5 ± 10.8 ms, p < .001).
CONCLUSIONS
Although LBBP's a physiological pacing mode can achieve a similar cardiac electrical and mechanical synchronization when compared to HBP, LBBP results in modest delay in RV activation, and the clinical implication remains to be studied.
Topics: Aged; Atrial Fibrillation; Bradycardia; Bundle of His; Bundle-Branch Block; Cardiac Pacing, Artificial; Female; Humans; Male
PubMed: 34337768
DOI: 10.1111/pace.14331 -
PloS One 2020Sheep have been adopted as a pre-clinical large animal for scientific research as they are good models of cardiac anatomy and physiology, and allow for investigation of...
INTRODUCTION
Sheep have been adopted as a pre-clinical large animal for scientific research as they are good models of cardiac anatomy and physiology, and allow for investigation of pathophysiological processes which occur in the large mammalian heart. There is, however, no defined model of atrioventricular block in sheep to allow for pre-clinical assessment of new cardiac treatment options. We therefore aimed to develop an adult sheep model of atrioventricular block with the focus on future novel applications.
METHODS AND RESULTS
We utilized six sheep to undergo two procedures each. The first procedure involved implantation of a single chamber pacemaker into the right ventricular apex, for baseline assessment over four weeks. The second procedure involved creating atrioventricular block by radiofrequency ablation of the His bundle, before holding for a further four weeks. Interrogation of pacemakers and electrocardiograms determined the persistence of atrioventricular block during the follow up period. Pacemakers were inserted, and atrioventricular block created in 6 animals using a conventional approach. One animal died following ablation of the His bundle, due to procedural complications. Four unablated sheep were assessed for baseline data over four weeks and showed 5.53 ± 1.28% pacing reliance. Five sheep were assessed over four weeks following His bundle ablation and showed continuous (98.89 ± 0.81%) ventricular pacing attributable to persistent atrioventricular block, with no major complications.
CONCLUSION
We have successfully developed, characterized and validated a large animal model of atrioventricular block that is stable and technically feasible in adult sheep. This model will allow for the advancement of novel therapies, including the development of cell and gene-based therapies.
Topics: Animals; Atrioventricular Block; Bundle of His; Catheter Ablation; Disease Models, Animal; Electrocardiography; Humans; Male; Pacemaker, Artificial; Sheep
PubMed: 32040499
DOI: 10.1371/journal.pone.0229092 -
Medicine Jul 2021Right ventricular pacing (RVP) has been widely accepted as a traditional pacing strategy, but long-term RVP has detrimental impact on ventricular synchrony. However,... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Right ventricular pacing (RVP) has been widely accepted as a traditional pacing strategy, but long-term RVP has detrimental impact on ventricular synchrony. However, left bundle branch pacing (LBBP) that evolved from His-bundle pacing could maintain ventricular synchrony and overcome its clinical deficiencies such as difficulty of lead implantation, His bundle damage, and high and unstable thresholds. This analysis aimed to appraise the clinical safety and efficacy of LBBP.
METHODS
The Medline, PubMed, Embase, and the Cochrane Library databases from inception to November 2020 were searched for studies comparing LBBP and RVP.
RESULTS
Seven trials with 451 patients (221 patients underwent LBBP and 230 patients underwent RVP) were included in the analysis. Pooled analyses verified that the paced QRS duration (QRSd) and left ventricular mechanical synchronization parameters of the LBBP capture were similar with the native-conduction mode (P > .7),but LBBP showed shorter QRS duration (weighted mean difference [WMD]: -33.32; 95% confidence interval [CI], -40.44 to -26.19, P < .001), better left ventricular mechanical synchrony (standard mean differences: -1.5; 95% CI: -1.85 to -1.14, P < .001) compared with RVP. No significant differences in Pacing threshold (WMD: 0.01; 95% CI: -0.08 to 0.09, P < .001), R wave amplitude (WMD: 0.04; 95% CI: -1.12 to 1.19, P = .95) were noted between LBBP and RVP. Ventricular impedance of LBBP was higher than that of RVP originally (WMD: 19.34; 95% CI: 3.13-35.56, P = .02), and there was no difference between the 2 groups after follow-up (WMD: 11.78; 95% CI: -24.48 to 48.04, P = .52). And follow-up pacing threshold of LBBP kept stability (WMD: 0.08; 95% CI: -0.09 to 0.25, P = .36). However, no statistical difference existed in ejection fraction between the 2 groups (WMD: 1.41; 95% CI: -1.72 to 4.54, P = .38).
CONCLUSIONS
The safety and efficacy of LBBP was firstly verified by meta-analysis to date. LBBP markedly preserve ventricular electrical and mechanical synchrony compared with RVP. Meanwhile, LBBP had stable and excellent pacing parameters. However, LBBP could not be significant difference in ejection fraction between RVP during short- term follow-up.
Topics: Bundle of His; Bundle-Branch Block; Cardiac Pacing, Artificial; Electrocardiography; Heart Rate; Heart Ventricles; Humans; Treatment Outcome; Ventricular Function, Left
PubMed: 34232199
DOI: 10.1097/MD.0000000000026560 -
Circulation. Arrhythmia and... Feb 2021Left 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...
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, <0.001). Postimplantation left ventricular ejection fraction improved in patients with QRS≥120 ms (48.82±17.78% versus 58.12±13.04%, <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.
Topics: Aged; Bundle of His; Bundle-Branch Block; Cardiac Pacing, Artificial; Electrocardiography; Feasibility Studies; Female; Follow-Up Studies; Heart Rate; Humans; Male; Prospective Studies; Time Factors; Treatment Outcome
PubMed: 33426907
DOI: 10.1161/CIRCEP.120.009261 -
PloS One 2017The Purkinje system (PS) and the His bundle have been recently implicated as an important driver of the rapid activation rate after 1-2 minutes of ventricular...
The Purkinje system (PS) and the His bundle have been recently implicated as an important driver of the rapid activation rate after 1-2 minutes of ventricular fibrillation (VF). It is unknown whether activations during VF propagate through the His-Purkinje system to other portions of the the working myocardium (WM). Little is known about restitution characteristic differences between the His bundle and working myocardium at short cycle lengths. In this study, rabbit hearts (n = 9) were isolated, Langendorff-perfused, and electromechanically uncoupled with blebbistatin (10 μM). Pacing pulses were delivered directly to the His bundle. By using standard glass microelectrodes, action potentials duration (APD) from the His bundle and WM were obtained simultaneously over a wide range of stimulation cycle lengths (CL). The global F-test indicated that the two restitution curves of the His bundle and the WM are statistically significantly different (P<0.05). Also, the APD of the His bundle was significantly shorter than that of WM throughout the whole pacing course (P<0.001). The CL at which alternans developed in the His bundle vs. the WM were shorter for the His bundle (134.2±13.1ms vs. 148.3±13.3ms, P<0.01) and 2:1 block developed at a shorter CL in the His bundle than in WM (130.0±10.0 vs. 145.6±14.2ms, P<0.01). The His bundle APD was significantly shorter than that of WM under both slow and rapid pacing rates, which suggest that there may be an excitable gap during VF and that the His bundle may conduct wavefronts from one bundle branch to the other at short cycle lengths and during VF.
Topics: Action Potentials; Animals; Bundle of His; In Vitro Techniques; Microelectrodes; Myocardium; Rabbits
PubMed: 29073179
DOI: 10.1371/journal.pone.0186880