Left bundle branch pacing set to outshine biventricular pacing for cardiac resynchronization therapy?

The deleterious effects of long-term right ventricular pacing necessitated the search for alternative pacing sites which could prevent or alleviate pacinginduced cardiomyopathy.Until recently,biventricular pacing(BiVP)was the only modality which could mitigate or prevent pacing induced dysfunction.Further,BiVP could resynchronize the baseline electromechanical dssynchrony in heart failure and improve outcomes.However,the high non-response rate of around 20%-30%remains a major limitation.This non-response has been largely attributable to the direct non-physiological stimulation of the left ventricular myocardium bypassing the conduction system.To overcome this limitation,the concept of conduction system pacing(CSP)came up.Despite initial success of the first CSP via His bundle pacing(HBP),certain drawbacks including lead instability and dislodgements,steep learning curve and rapid battery depletion on many occasions prevented its widespread use for cardiac resynchronization therapy(CRT).Subsequently,CSP via left bundle branch-area pacing(LBBP)was developed in 2018,which over the last few years has shown efficacy comparable to BiVP-CRT in small observational studies.Further,its safety has also been well established and is largely free of the pitfalls of the HBP-CRT.In the recent metanalysis by Yasmin et al,comprising of 6 studies with 389 participants,LBBPCRT was superior to BiVP-CRT in terms of QRS duration,left ventricular ejection fraction,cardiac chamber dimensions,lead thresholds,and functional status amongst heart failure patients with left bundle branch block.However,there are important limitations of the study including the small overall numbers,inclusion of only a single small randomized controlled trial(RCT)and a small follow-up duration.Further,the entire study population analyzed was from China which makes generalizability a concern.Despite the concerns,the meta-analysis adds to the growing body of evidence demonstrating the efficacy of LBBP-CRT.At this stage,one must acknowledge that the fact that still our opinions on this technique are largely based on observational data and there is a dire need for larger RCTs to ascertain the position of LBBPCRT in management of heart failure patients with left bundle branch block.

Left bundle branch pacing vs biventricular pacing in heart failure patients with left bundle branch block:A systematic review and meta-analysis

BACKGROUND Left bundle branch pacing(LBBP)is a novel pacing modality of cardiac resynchronization therapy(CRT)that achieves more physiologic native ventricular activation than biventricular pacing(BiVP).AIM To explore the validity of electromechanical resynchronization,clinical and echocardiographic response of LBBP-CRT.METHODS Systematic review and Meta-analysis were conducted in accordance with the standard guidelines as mentioned in detail in the methodology section.RESULTS In our analysis,the success rate of LBBP-CRT was determined to be 91.1%.LBBP CRT significantly shortened QRS duration,with significant improvement in echocardiographic parameters,including left ventricular ejection fraction,left ventricular end-diastolic diameter and left ventricular end-systolic diameter in comparison with BiVP-CRT.CONCLUSION A significant reduction in New York Heart Association class and B-type natriuretic peptide levels was also observed in the LBBP-CRT group vs BiVP-CRT group.Lastly,the LBBP-CRT cohort had a reduced pacing threshold at follow-up as compared to BiVP-CRT.

Left bundle branch area pacing combined with implantable cardioverter-defibrillator treatment for heart failure after myocardial infarction

Left bundle branch area pacing(LBBAP)has emerged as a new physiological pacing mode.Previous studies have confirmed the feasibility and efficacy of LBBAP for cardiac resynchronization therapy(CRT)in heart failure(HF)patients with left bundle branch block(LBBB)and a narrower QRS duration(QRSd)to have a higher percentage of super responders,and lower pacing thresholds than biventricular pacing(BiVP).

Selective his bundle pacing eliminates crochetage sign:A case report

BACKGROUND Crochetage sign is a specific electrocardiographic manifestation of ostium secundum atrial septal defects(ASDs),which is associated with the severity of the left-to-right shunt.Herein,we reported a case of selective his bundle pacing(SHBP)that eliminated crochetage sign in a patient with ostium secundum ASD.CASE SUMMARY A 77-year-old man was admitted with a 2-year history of chest tightness and shortness of breath.Transthoracic echocardiography revealed an ostium secundum ASD.Twelve-lead electrocardiogram revealed atrial fibrillation with a prolonged relative risk interval,incomplete right bundle branch block,and crochetage sign.The patient was diagnosed with an ostium secundum ASD,atrial fibrillation with a second-degree atrioventricular block,and heart failure.The patient was treated with selective his bundle pacemaker implantation.After the procedure,crochetage sign disappeared during his bundle pacing on the electrocardiogram.CONCLUSION S-HBP eliminated crochetage sign on electrocardiogram.Crochetage sign may be a manifestation of a conduction system disorder.

Management of a patient with an unusual trajectory of a temporary trans-venous pacing lead

Perforation of the right ventricle during placement of pacing wires is a welldocumented complication and can be potentially fatal.Use of temporary pacemaker,helical screw leads and steroids use prior to implant are recognised as risk factors for development of post-permanent pacemaker effusion.We reported an unusual case of pacing wire perforating interventricular septum into the left ventricle that occurred during the implant procedure performed in another institution.After the preoperative work-up and transfer to our tertiary cardiothoracic centre,the patient underwent successful surgical management.In conclusion,early recognition and timely diagnosis using advanced multimodality imaging can guide surgical intervention and prevent unfavourable consequences of device-related complications.

Analysis of the Effect of Extracorporeal Diaphragmatic Pacing Combined with Noninvasive Ventilator on the Respiratory Function and Prognosis of COPD Patients

Objective: To investigate the effect of extracorporeal diaphragmatic pacing combined with noninvasive ventilators on the respiratory function and prognosis of chronic obstructive pulmonary disease (COPD) patients. Methods: A total of 50 COPD patients were selected between January 2023 to December 2023 and randomly grouped into an observation group and a control group, with 25 cases. The observation group was given extracorporeal diaphragm pacing combined with a noninvasive ventilator, while the control group was given a conventional treatment mode. After the treatment, the results of each index in the two groups were compared. Results: Compared with the diaphragm function indexes of the two groups, the data of the observation group were more dominant (P < 0.05). The rehospitalization rate of the observation group was lower than that of the control group (P < 0.05). The COPD assessment test (CAT) and mMRC (Modified Medical Research Council) Dyspnoea scale scores after treatment between the two groups were significantly different (P < 0.05). Compared with the control group, the lung function indexes of the observation group were more dominant (P < 0.05). Conclusion: Extracorporeal diaphragmatic pacing combined with a noninvasive ventilator promoted the improvement of the patient’s prognosis and improved their respiratory function.

The Impact of Cardiac Pacing Site on Patient's Cardiac Function and Psychological State

With the widespread application of artificial permanent pacemakers in clinical practice,there have been new changes in the indications for pacemaker implantation.The current clinical indications include high atrioventricular block,sick sinus syndrome,cardiac resynchronization therapy for heart failure,and implantation of cardioverter defibrillators for ventricular arrhythmias.The implantation of a pacemaker can improve the quality of life and prognosis of patients with arrhythmia.In the past,permanent pacemaker implantation was performed in clinical practice,and the right ventricular pacing electrode was often fixed at the apex of the right ventricle,which belongs to non physiological pacing.Through long-term clinical follow-up,it was found that apex pacing can easily cause abnormal depolarization of the left ventricle,asynchronous contraction of the myocardium,and ultimately lead to myocardial fibrosis,which has adverse effects on the patient's cardiac function and psychological state.In recent years,Scholars have found that pacing in the right ventricular outflow tract septum is closer to the atrioventricular node and closer to the His bundle Purkinje fibers.The pacing impulse almost simultaneously expands towards both ventricles,closer to the physiological pacing state,thereby reducing the occurrence of cardiovascular events in patients.This article explores the impact of pacing in different parts of the heart on the cardiac function and psychological state of patients based on clinical data from the past three years.

Inadvertent Lead Malposition in the Left Ventricle during Permanent Ventricular Pacing about One Case

Inadvertent Lead Malposition in Left Ventricle is a rare and underdiagnosed incident, which may occur during implantation of cardiac electronic devices and may remain asymptomatic. We reported the case of a 71-year-old man who was implanted with a ventricular single-chamber pacemaker for a slow atrial fibrillation with syncope and whose routine transthoracic echocardiography 23 months after implantation displayed a malposition of the pacemaker lead into the Left Ventricle through a patent foramen oval. The patient was asymptomatic. The electrocardiogram showed right bundle branch block QRS-paced morphology with a positive QRS pattern in V1, a median paced QRS axis on the frontal plane at -120°, a Precordial transition on V5. At the lateral Chest X-ray the lead curved backwards to the spine. Given the age of this old patient who already received oral anticoagulant for Atrial Fibrillation and the Lead malposition discovered 23 months after pacemaker’s implantation, we decided to maintain the lead in LV and continue anticoagulation.

Left bundle branch pacing in a ventricular pacing dependent patient with heart failure:A case report

BACKGROUND Left bundle branch pacing(LBBP)is a physiological pacing method that has emerged in recent years.It is an ideal choice for patients with complete left bundle branch block who are in need of cardiac resynchronization therapy(CRT).Moreover,LBBP is superior in maintaining physiological ventricular activation and can effectively improve heart function and quality of life in patients with pacemaker-induced cardiomyopathy.However,LBBP in pacing-dependent patients who already have cardiac dysfunction has not been well assessed.CASE SUMMARY A 69-year-old male patient presented with symptoms of chest tightness,palpitation and systolic heart failure with New York Heart Association class III for 1 mo.The 12-lead electrocardiogram showed atrial fibrillation with third-degree atrioventricular block and ventricular premature beat.Holter revealed a right bundle branch block,atrial fibrillation with third-degree atrioventricular block,frequent multifocal ventricular premature beats,Ron-T and ventricular tachycardia.The echocardiogram documented an enlarged left atrium and left ventricle and a low left ventricular ejection fraction.Coronary angiography indicated a stenosis of 30%in the middle left anterior descending artery.Apparently,a CRT-D pacemaker was the best choice for this patient according to previous findings.However,the patient was worried about the financial burden.A single-chamber pacemaker with LBBP was selected,with the plan to take amiodarone and upgrade with dual-chamber implantable cardioverter-defibrillator or CRT-D at an appropriate time.During the follow-up at 3 mo after LBBP,the patient showed an improvement in cardiac function with slight improvement in echocardiography parameters,and the New York Heart Association functional class was maintained at I.Moreover,the patient no longer suffered from chest tightness and palpitation.Holter showed decreased ventricular arrhythmia of less than 5%.CONCLUSION LBBP might be used in patients with heart failure and a high-degree atrioventricular block as an alternative to conventional CRT.

Right ventricular septal pacing: Safety and efficacy in a long term follow up

AIM: To evaluate the safety and efficacy of the permanent high interventricular septal pacing in a long term follow up, as alternative to right ventricular apical pacing. METHODS: We retrospectively evaluated:(1) 244 patients(74 ± 8 years; 169 men, 75 women) implanted with a single(132 pts) or dual chamber(112 pts) pacemaker(PM) with ventricular screw-in lead placed at the right ventricular high septal parahisian site(SEPTAL pacing);(2) 22 patients with permanent pacemaker and low percentage of pacing(< 20%)(NO pacing);(3) 33 patients with high percentage(> 80%) right ventricular apical pacing(RVA). All patients had a narrow spontaneous QRS(101 ± 14 ms). We evaluated New York Heart Association(NYHA) class, quality of life(Qo L), 6 min walking test(6MWT) and left ventricular function(end-diastolic volume, LV-EDV; end-systolic volume, LVESV; ejection fraction, LV-EF) with 2D-echocardiography. RESULTS: Pacing parameters were stable duringfollow up(21 mo/patient). In SEPTAL pacing group we observed an improvement in NYHA class, Qo L score and 6MWT. While LV-EDV didn't significantly increase(104 ± 40 m L vs 100 ± 37 m L; P = 0.35), LV-ESV slightly increased(55 ± 31 m L vs 49 ± 27 m L; P = 0.05) and LV-EF slightly decreased(49% ± 11% vs 53% ± 11%; P = 0.001) but never falling < 45%. In the RVA pacing control group we observed a worsening of NYHA class and an important reduction of LV-EF(from 56% ± 6% to 43% ± 9%, P < 0.0001).CONCLUSION: Right ventricular permanent high septal pacing is safe and effective in a long term follow up evaluation; it could be a good alternative to the conventional RVA pacing in order to avoid its deleterious effects.

Future easy and physiological cardiac pacing

The right atrial appendage (RAA) and right ventricular apex (RVA) have been widely considered as conventional sites for typical dual-chamber atrio-ventricular cardiac (DDD) pacing. Unfortunately conventional RAA pacing seems not to be able to prevent atrial fibrillation in DDD pacing for tachycardia-bradycardia syndrome, and the presence of a left bundle branch type of activation induced by RVA pacing can have negative effects. A new technology with active screw-in leads permits a more physiological atrial and right ventricular pacing. In this review, we highlight the positive effects of pacing of these new and easily selected sites. The septal atrial lead permits a shorter and more homogeneous atrial activation, allowing better prevention of paroxysmal atrial fibrillation. The para-Hisian pacing can be achieved in a simpler and more reliable way with respect to biventricular pacing and direct Hisian pacing. We await larger trials to consider this "easy and physiological pacing" as a first approach in patients who need a high frequency of pacing.

The importance of avoiding unnecessary right ventricular pacing in clinical practice

Symptomatic bradycardia is effectively treated with the implantation of a cardiac pacemaker. Although a highly successful therapy, during recent years there has been a focus on the negative effects associated with longterm pacing of the apex of the right ventricle(RV). It has been shown in both experimental and clinical studies that RV pacing leads to ventricular dyssynchrony, similar to that of left bundle branch block, with subsequent detrimental effects on cardiac structure and function, and in some cases adverse clinical outcomes such as atrial fibrillation, heart failure and death. There is substantial evidence that patients with reduced left ventricular function(LVEF) are at particular high risk of suffering the detrimental clinical effects of long-term RV pacing. The evidence is, however, incomplete, coming largely from subanalyses of pacemaker and implantable cardiac defibrillator studies. In this group of patients with reduced LVEF and an expected high amount of RV pacing, biventricular pacing(cardiac resynchronization therapy) devices can prevent the negative effects of RV pacing and reduce ventricular dyssynchrony. Therefore, cardiac resynchronization therapy has emerged as an attractive option with promising results and more clinical studies are underway. Furthermore, specific pacemaker algorithms, which minimize RV pacing, can also reduce the negative effects of RV stimulation on cardiac function and may prevent clinical deterioration.

Right Ventricular Outflow Tract Septal Pacing versus Apical Pacing: A Prospective, Randomized, Single-blind 5-Years Follow-up Study of Ventricular Lead Performance and Safety

Summary： Lead placement for ventricular pacing variably impacts the physiological benefit of the pa- tient. This study evaluated the ventricular lead performance and safety of right ventricular outflow tract septal pacing in patients with bradyarrhythmia in South China over 60-month follow-up. Totally, 192 patients （108 males, and 84 females, 63-4-21 years old） with bradyarrhythmia were randomly divided into two groups. The right ventricular outflow tract septum （RVOTs） group had lead placement near the sep- tum （n=97）, while the right ventricular apex （RVA） group had a traditional apical placement （n=95）. RV septal lead positioning was achieved with a specialized stylet and confirmed using fluoroscopic projec- tion. All patients were followed up for 60 months. Follow-up assessment included stimulation threshold, R-wave sensing, lead impedance and lead complications. The time of electrode implantation in both the ROVTs and RVA groups were significantly different （4.29±0.61 vs. 2.16±0.22 min; P=0.009）. No dif- ferences were identified in threshold, impedance or R-wave sensing between the two groups at 1 st, 12th, 36th and 60th month during the follow-up period. No occurrence of electrode displacement, increased pacing threshold or inadequate sensing was found. The long-term active fixation ventricular electrode performance in RVOTs group was similar to that in RVA group. RVOTs pacing near the septum using active fixation electrodes may provide stability during long-term follow-up period.

Effects of febuxostat on atrial remodeling in a rabbit model of atrial fibrillation induced by rapid atrial pacing

Background Febuxostat,a novel nonpurine selective inhibitor of xanthine oxidase(XO),may be used in the prevention and management of atrial fibrillation(AF).The purpose of this study was to evaluate the effects of febuxostat on atrial remodeling in a rabbit model of AF induced by rapid atrial pacing(RAP)and the mechanisms by which it acts.Methods Twenty-four rabbits were randomly divided into four groups:sham-operated group(Group S),RAP group(Group P),RAP with 5 mg/kg per day febuxostat group(Group LFP),and RAP with 10 mg/kg per day febuxostat group(Group HFP).All rabbits except those in Group S were subjected to RAP at 600 beats/min for four weeks.The effects of febuxostat on atrial electrical and structural remodeling,markers of inflammation and oxidative stress,and signaling pathways involved in the left atrium were examined.Results Shortened atrial effective refractory period(AERP),increased AF inducibility,decreased mRNA levels of Cav1.2 and Kv4.3,and left atrial enlargement and dysfunction were observed in Group P,and these changes were suppressed in the groups treated with febuxostat.Prominent atrial fibrosis was observed in Group P,as were increased levels of TGF-β1,Collagen I,andα-SMA and decreased levels of Smad7 and eNOS.Treatment with febuxostat attenuated these differences.Changes in inflammatory and oxidative stress markers induced by RAP were consistent with the protective effects of febuxostat.Conclusions This study is the first to find that febuxostat can inhibit atrial electrical and structural remodeling of AF by suppressing XO and inhibiting the TGF-β1/Smad signaling pathway.

In vivo mechanical study of helical cardiac pacing electrode interacting with canine myocardium

Cardiac pacing is a medical device to help human to overcome arrhythmia and to recover the regular beats of heart. A helical configuration of electrode tip is a new type of cardiac pacing lead distal tip. The helical electrode attaches itself to the desired site of heart by screwing its helical tip into the myocardium. In vivo experiments on anesthetized dogs were carried out to measure the acute interactions between helical electrode and myocardium during screw-in and pull-out processes. These data would be helpful for electrode tip design and electrode/myocardium adherence safety evaluation. They also provide reliability data for clinical site choice of human heart to implant and to fix the pacing lead. A special design of the helical tip using strain gauges is instrumented for the measurement of the screw-in and pull-out forces. We obtained the data of screw-in torques and pull-out forces for five different types of helical electrodes at nine designed sites on ten canine hearts. The results indicate that the screw-in torques increased steplike while the torque-time curves presente saw-tooth fashion. The maximum torque has a range of 0.3-1.9 Nmm. Obvious differences are observed for different types of helical tips and for different test sites. Large pull-out forces are frequently obtained at epicardium of left ventricle and right ventricle lateral wall, and the forces obtained at right ventricle apex and outflow tract of right ventricle are normally small. The differences in pull-out forces are dictated by the geometrical configuration of helix and regional structures of heart muscle.

Biventricular pacing for treating heart failure in children: A case report and review of the literature

BACKGROUND Cardiac resynchronization therapy(CRT) can be used as an escalated therapy to improve heart function in patients with cardiac dysfunction due to long-term right ventricular pacing. However, guidelines are only targeted at adults. CRT is rarely used in children.CASE SUMMARY This case aimed to implement biventricular pacing in one child with heart failure who had a left ventricular ejection fraction < 35% at 4 years after implantation of an atrioventricular sequential pacemaker due to atrioventricular block.Postoperatively, echocardiography showed atrial sensing ventricular pacing and QRS wave duration of 120-130 ms, and cardiac function significantly improved after upgrading pacemaker.CONCLUSION Patients whose cardiac function is deteriorated to a level to upgrade to CRT should be upgraded to reverse myocardial remodeling as soon as possible.

Hemodynamic improvement by right ventricular septal pacing in elderly patients with chronic atrial fibrillation and slow ventricular response

Background and objectives Right ventricular apical (RVA) pacing has been reported impairing left ventricular (LV)performance. Alternative pacing sites in right ventricle (RV) has been explored to obtain better cardiac function. Our study was designed to compare the hemodynamic effects of right ventricular septal (RVS) pacing with RVA pacing. Methods Ten elderly patients with chronic atrial fibrillation (AF) and long RR interval or slow ventricular response (VR) received VVI pacing. The hemodynamic difference between RVS and RVA pacing were examined by transthoracic echocardiography (TTE). Results Pacing leads were implanted successfully at the RVA and then RVS in all patients without complication. The left ventricular (LV) parameters,measured during RVA pacing including left ventricular ejection fraction (LVEF), FS, stroke volume (SV) and peak E wave velocity (EV) were decreased significantly compared to baseline data, while during RVS pacing, they were significantly better than those during RVA pacing. However, after 3-6 weeks there was no statistical significant difference between pre- and post- RVS pacing.Conclusions The LV hemodynamic parameters during RVA pacing were significantly worse than baseline data. The short term LV hemodynamic parameters of RVS pacing were significantly better than those of RVA pacing; RVS pacing could improve the hemodynamic effect through maintaining normal ventricular activation sequence and biventricular contraction synchrony in patients with chronic AF and slow ventricular response.

Minimizing right ventricular pacing in sinus node disease: Sometimes the cure is worse than the disease

Traditional right ventricular(RV) apical pacing has been associated with heart failure, atrial fibrillation and increased mortality. To avoid the negative consequences of RV apical pacing different strategies have been developed, among these a series of pacing algorithms designed to minimize RV pacing. These functions are particularly useful when there is not the need for continuous RV pacing: intermittent atrioventricular blocks and, mainly, sinus node disease. However, in order to avoid RV pacing, the operationalfeatures of these algorithms may lead to adverse(often under-appreciated) consequences in some patients. We describe a case of a patient with sinus node disease, in whom right atrial only pacing involved long atrio-ventricular delay to allow intrinsic ventricular conduction, which led to symptomatic hypotension that could be overcome only by "forcing" also right ventricular apical pacing. We subsequently discuss this case in the context of current available literature.

Transoesophageal emergency ventricular pacing with esophageal balloon electrode catheter

Objective To evaluate the safety and possibility of transesophageal emergency ventricular pacing with esophageal balloon electrode catheter.Methods Sixty four patients with critical bradyarrhythmias were divided randomly to receive either transesophageal ventricular pacing with esophageal balloon electrode catheter (balloon catheter group,n=32),or transesophageal ventricular pacing with normal esophageal electrode catheter (normal catheter group,n=32).Pulse width (ms),current output (mA),and the success rate were compared between the 2 groups.Results Success rate in the balloon catheter group was 87.5%,which was significantly higher than that in the normal catheter group (18.7%,x^2=27.7,P【0.01).The success rate of transesophageal ventricular pacing with esophageal balloon electrode catheter was 87.5%.The average current output (mA) was significantly lower in the balloon catheter group than that in the normal catheter group (24.5±2.5 mA vs 53±3.4mA,P【0.05).Conclusions Esophageal balloon electrode catheter pacing could become an available technique for transesophageal emergency ventricular pacing.

His Bundle Pacing:Rebirth of an Important Technique for Pacing the Intrinsic Conduction System

Permanent pacemaker implant is a commonly performed cardiac procedure for treatment of bradycardia or conduction system abnormality.With conventional right ventricular(RV)pacing a lead is implanted at the RV apex or on the RV septum.However,RV apical or RV septal pacing causes iatrogenic left bundle-branch block and ventricular dyssynchrony and can lead to adverse cardiac remodeling,a pacing-mediated cardiomyopathy,and congestive heart failure.Alternatively,permanent His-bundle pacing uses the intrinsic rapidly-conducting His-Purkinje system to activate the ventricle,thereby maintaining(or sometimes even restoring)ventricular synchrony.Many patients may derive benefit from permanent His-bundle pacing.