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:A new era of cardiac resynchronization therapy?

The recent systematic review and meta-analysis provided a comprehensive focus on the current state of cardiac resynchronization therapy(CRT).The authors determined the feasibility of physiological left bundle branch area pacing(LBBAP)in patients indicated for CRT through a careful analysis of trials.They found that LBBAP was associated with significant reductions in QRS duration,New York Heart Association functional class,B-type natriuretic peptide levels,and pacing thresholds as well as improvements in echocardiographic parameters compared to biventricular pacing.

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.

Cardiac resynchronization therapy for heart failure induced by left bundle branch block after transcatheter closure of ventricular septal defect

A 54-year-old female patient with congenital heart disease had a persistent complete left bundle branch block three months after closure by an Amplatzer ventricular septal defect occluder. Nine months later, the patient suffered from chest distress, palpitation, and sweating at daily activities, and her 6-min walk distance decreased significantly （155 m）. Her echocardiography showed increased left ventricular end-diastolic diameter with left ventricular ejection fraction of 37%. Her symptoms reduced significantly one week after received cardiac resynchronization therapy. She had no symptoms at daily activities, and her echo showed left ventricular ejection fraction of 46%and 53%. Moreover, left ventricular end-diastolic diameter decreased 6 and 10 months after cardiac resynchronization therapy, and 6-min walk dis-tance remarkably increased. This case demonstrated that persistent complete left bundle branch block for nine months after transcatheter closure with ventricular septal defect Amplatzer occluder could lead to left ventricular enlargement and a significant decrease in left ventricular systolic function. Cardiac resynchronization therapy decreased left ventricular end-diastolic diameter and increased left ventricular ejection fraction, thereby improving the patient’s heart functions.

Delayed spontaneous reversibility of left bundle branch block in non-ischemic cardiomyopathy: a case report

Left bundle branch block(LBBB)causes a delay in left ventricular contraction with an unsynchronized ventricular systole.LBBB is an independent determinant of morbi-mortality mainly when associated with cardiomyopathy and left ventricular dysfunction.[1] LBBB due to non-ischemic cardiomyopathy is considered non-reversible.Such irreversibility occurs because LBBB and cardiomyopathy act in a synergic manner in order to maintain both situations.However,there are a few reports in the literature showing that some patients have had an improvement in cardiac function with normalization of QRS and have experienced a reverse remodelling with pharmacological therapy only.[2–4]

Exercise-induced left bundle branch block: an infrequent phenomenon: Report of two cases

Exercise-induced left bundle branch block(EI-LBBB)is infrequent phenomenon.We present two patients with angina pectoris who developed EI-LBBB during exercise tolerance test.The first patient with typical angina pectoris had significant obstructive coronary artery disease(CAD)requiring percutaneous coronary intervention of multiple lesions including placement of drug eluting stents.The second patient had atypical chest pain without signs of CAD at all.EI-LBBB occurred at a heart rate of 80 bpm and 141 bpm in the first and second patient,respectively.EI-LBBB remained visible through the test till the recovery period in the first patient at a heart rate of 83 bpm and disappeared at 96bpm in the second patient.Both patients with this infrequent phenomenon are discussed and the literature is reviewed.

Left bundle branch pacing with optimization of cardiac resynchronization treatment:A case report

BACKGROUND Cardiac resynchronization therapy(CRT)is a well-established therapy for patients with cardiomyopathy.CASE SUMMARY The patient underwent left bundle branch area and left ventricular(reaching the left ventricular lateral vein through the coronary sinus)pacing.The optimal CRT was performed under the right bundle branch of the patient by adjusting the optimal a-v and v-v interphases to achieve the maximal benefit of the treatment.CONCLUSION The patient was diagnosed with left bundle branch block and heart failure.A left bundle branch area pacemaker assisted in correcting the complete left bundle branch block.However,the shorter QRS wave shape after pacemaker implantation through the left bundle branch area indicated a complete right bundle branch block pattern.Hence,the left bundle branch area pacemaker is not always considered as the optimal treatment.The left bundle branch pacing with the optimization of cardiac resynchronization treatment may serve as a new CRT strategy.

Differential diagnosis of tachycardia with a typical left bundle branch block morphology

The evaluation of wide QRS complex tachycardias (WCT)remains a common dilemma for clinicians.Numerous algorithms exist to aid in arriving at the correct diagnosis.Unfortunately,these algorithms are difficult to remember,and overreliance on them may prevent cardiologists from understanding the mechanisms underlying these arrhythmias.One distinct subcategory of WCTs are those that present with a"typical"or"classic" left bundle branch block pattern.These tachycardias may be supraventricular or ventricular in origin and arise from functional or fixed aberrancy,bystander or participating atriofascicular pre-excitation,and bundle branch reentry.This review will describe these arrhythmias,illustrate their mechanisms,and discuss their clinical features and treatment strategies.

Short-term efficacy of unibody single-branched stent in the treatment of lesions involving the left subclavian artery:two-year follow-up outcomes

The development of thoracic endovascular aortic repair(TEVAR)technology avoids the risk of patients opening the chest and is widely used in Stanford B-type dissection.[1–3]However,because TEVAR technology has clear requirements for vascular anatomy of the lesion,it limits its application to some patients.In the shortcomings of the proximal anchor zone,coverage of the left subclavian artery(LSA)origin without revascularization during TEVAR appears to have increased risk of stroke,upper extremity ischemia and paraplegia.[4]

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.

A Case of Premature Ventricular Complexes from the Proximal Left Bundle Branch Successfully Ablated from the Right Coronary Cusp

Background:Premature ventricular complexes(PVCs)from the proximal left bundle branch(LBB)can be ablated in the left ventricular outflow tract but can easily damage normal conduction bundles.Here,we report a case of successful ablation of PVCs from the proximal LBB within the right coronary cusp(RCC).Case presentation:Our patient was a 70-year-old woman with PVCs from the proximal LBB that were successfully ablated via the RCC through radiofrequency catheter ablation with a 3D mapping system;she had a complication of incomplete right bundle branch block(RBBB)and remained asymptomatic during follow-up.Conclusion:The RCC provides an alternative approach for ablating PVCs originating from the proximal LBB,ow-ing to the close relationship between the RCC and proximal LBB.

Cardiovascular Risk in Young Workers with Left Bundle Branch Block

Aims: Left bundle branch block (LBBB) is generally associated with a poorer prognosis in comparison to normal intraventricular conduction, but also in comparison to right bundle branch block which is generally considered to be benign in the absence of an underlying cardiac disorder like congenital heart disease. In this paper we evaluate the presence of possible cardiovascular pathology in a group of nurses with a low level of cardiovascular risk factors and left bundle branch block (LBBB). Methods: During the period 2009-2013, 356 nurses (mean age: 32.6 ± 11 yr) were admitted to the department of Occupational Medicine of Second University of Naples. Of these, 13 had LBBB. The evaluation of these patients has included an electrocardiogram (ECG), echocardiography, 24-h ambulatory Holter monitoring (ECG Holter), and exercise testing. Subsequently, in patients with LBBB, multislice computed coronary angiography (MSCT) has been considered. Results and Conclusion: Only in one patient we found a significant stenosis in the middle tract of left anterior descending artery. Coronary artery disease remains difficult to diagnose in some ECG findings such as acquired LBBB. For this reason, a preventive diagnose with newly developed diagnostic methods such as the multislice computed coronary angiography (MSCT) must try to account by the clinician in order to ruling out coronary artery disease (CAD) in workers with LBBB and low cardiovascular risk.

Prognostic implication of the coronary microvascular dysfunction in patients with isolated left bundle branch block

The present study aims to determine the influence of microvascular dysfunction (MVD) in the prognosis of patients presenting isolated left bundle branch block (LBBB). Methods: We studied 30 patients (pts), 22 males, 8 females, mean age 57 ± 4 years, with isolated LBBB, with a mean follow up of 48 ± 6 months. The control group consisted of 20 healthy individuals, 12 males, mean age 52 ± 10 years. Both groups were screened for cardiovascular risk factors (RF);they also had an echocardiogram and Coronary CT Scan, ruling out both structural heart disease and obstructive lesions of the epicardial coronary arteries. A myocardial perfusion study was then performed, with two groups emerging according to these results: Group A, 8 pts (26%), with reversible perfusion defects, in which the diagnosis of MVD was suspected, and Group B, 22 pts (74%), with either normal perfusion or minor septal/apical reversible defects (related to LBBB). All Group A pts, and 9 of the Group B pts, underwent coronary arteriography, with intracoronary acetylcholine and nitroglycerine infusion, thus evaluating vasomotor response as endothelium dependent (acetylcholine) or endothelium independent (nitroglycerine). During follow up, we reviewed functional class, 12 lead ECG and echocardiogram on a yearly basis. Results: All Group A patients had an abnormal acetylcholine response;only three of them had abnormal response to nitroglycerine infusion, suggesting endothelium dependent MVD. Of those in Group B, only one patient had abnormal acetylcholine response. At the end of the follow up period, 3 pts (37%) in Group A, showed functional class decrease vs 5 pts (22%) of those in Group B. In Group A, a significant increase of End Diastolic Left Ventricle Diameter (EDLVD) was found (51.6 ± 3.6 vs 59.3 ± 6.8 mm;p < 0.05) with significant decrease in LVEF (62 ± 4.8 vs 46% ± 3.7%, p variation. In neither group major complications (death, heart failure admissions) were found. Conclusion: We confirm the association between MVD and a worse clinical prognosis in isolated LBBB patients. Repeated ischemia and myocardial fibrosis are highlighted as possible physiopathological mechanisms, precluding a progressive left ventricular function decrease, with a higher mortality and arrhythmia risk. Endothelial function preserving strategies, both preventive and therapeutic, might be useful in improving LBBB with MVD patient’s prognosis.

Clinical Profile of the Patients with Newly Detected Left Bundle Branch Block in the Outpatient Department

Objective: The purpose of this study was to evaluate cardiac features associated with newly detected left bundle branch block (LBBB) in the outpatient department. Methods: A total of 57 patients with LBBB pattern were evaluated using electrocardiography (ECG). Patients were assessed based on their sex, age, detailed history, and cardiovascular symptoms. Cardiac investigations including ECG and echocardiography were performed. Results:The study included 30 (52.6%) males and 27 (47.5%) females, aged between 35 and 80 years. Dyspnoea (35.1%) and chest pain (22.8%) were the most common symptoms. 54.4% were hypertensive and 17.5% were diabetics. 28% had Left ventricular systolic dysfunction, and 24.5% had aortic valve disease. Left ventricular hypertrophy without any other structural heart disease was present in 28% of the patients. Only 24.5% patients presented with LBBB had a structurally normal heart in echocardiography. Myocardial performance index in echocardiography was abnormal in LBBB irrespective of the presence of structural heart disease. Conclusion: The prevalence of LBBB was found to increase with age and had slight male preponderance. Dyspnoea on effort was the most common presenting complaint, followed by chest pain and incidental detection of ECG abnormality. Most of the patients were hypertensive. Only 24.5% patients with LBBB had a structurally normal heart. MPI was abnormally high in the presence of LBBB despite having a normal left ventricular ejection fraction.

Left bundle branch block and myocardial infarction, a diagnosis not always easy: Our experience and review of literature

The occurrence of left bundle branch block (LBBB) is quite common in clinical practice. The changes in cardiac repolarization, caused by this disorder of electric conduction, may mask the presence of an acute myocardial infarction (AMI), delaying the diagnostic-therapeutic iter, with an important impact on prognosis. We describe the case of a woman of 59 years with LBBB, came to our observation for a constrictive chest pain associated with dyspnea. The diagnostic workup for suspected acute coronary syndrome (ACS), initially conducted only on the analysis of the electrocardiogram (negative TnI at entry), showed the presence of coronary arteries free of stenosis. However, the diagnostic confirmation of AMI was completed after the rise of cardiac markers and the electrocardiographic changes. This case confirm the difficulty about the diagnosis of AMI in patients with LBBB and stresses, however, as the use of some criteria proposed in the literature [1-3] can guide to its identification, directing patient to an appropriate treatment.

Can regadenoson pharmacologic SPECT be performed effectively in patients with left bundle branch block or paced rhythm patients? A retrospective comparison to adenosine SPECT

Purpose: Regadenoson (REG) is currently becoming the stress agent of choice in patients undergoing pharmacologic single photon emission computed tomography (SPECT). However, in patients with left bundle branch block (LBBB) and ventricular paced rhythm (VPR), hesitation exists amongst clinicians to use REG-SPECT due to the concern that the increased heart rate could cause false positive SPECT results. We sought to evaluate the comparability of A-SPECT and REG-SPECT in patients with LBBB and VPR. Methods: Retrospective study of 30 patients who served as their own controls. All 30 patients who underwent REG-SPECT (Grp 1) were compared to their prior A-SPECT (Grp 2) done within two years prior to REG-SPECT. Heart rate (HR) and blood pressure (BP) parameters, ECG, stress perfusion and gated variables, SPECT ischemia, and side-effects were evaluated. Statistical significance was set at P < 0.05. Results: Grp 1 and Grp 2 were comparable in hemodynamic parameters with increase in HR and decrease in systolic and diastolic BP with administration of adenosine and REG stress agents. However, there were no significant differences found in hemodynamic parameters and II degree AV block between the groups. All normal A-SPECT were found to be normal with REG-SPECT. No differences could be found between the two groups among SPECT parameters. Muscle pain was significantly higher in REG (10.0% vs. 0.0%, P = 0.083) and so was the use of aminophylline (16.7% vs. 0.0%, P = 0.025) to relieve the side-effect. Conclusion: REG-SPECT can be administered in patients with LBBB and VPR patients based on favorable and comparable hemodynamic responses and arrhythmia occurrences to A-SPECT. REG-SPECT can also be used for adequate interpretation of presence or absence of SPECT ischemia particularly in the LAD territory without any concern for false positive perfusion defects.

V_(1)导联r'波振幅结合阻抗变化评价左束支区域起搏电极植入深度的研究

目的:探讨左束支区域起搏时,V_(1)导联r’波振幅结合阻抗变化判断电极植入的合适深度。方法:纳入2019年1月1日至2021年12月31日于南昌大学第二附属医院就诊的心脏结构正常、有起搏器植入指征并行左束支区域起搏的住院患者78例,收集患者基线数据、术中数据和影像学资料,以及术后3、6、9和12个月的随访情况。将起搏时V_(1)导联r’波振幅、阻抗、电极植入深度进行线性相关性及回归分析。结果:78例患者中70例(89.7%)起搏时V_(1)导联QRS波末端出现r’波,8例(10.3%)QRS波表现为r S、RS型或终末端无r’波。线性相关性分析显示,r’波振幅与电极植入深度呈正相关(r=0.424,P<0.01),与阻抗呈负相关(r=-0.256,P=0.03);电极植入深度与阻抗无明显相关性(r=-0.132,P=0.27)。回归分析显示,电极植入深度是r’波振幅的重要影响因素(回归系数=0.056,P=0.000)。结合建立的回归模型和阻抗大小显示,V_(1)导联r’波振幅在0.24~0.69 mV范围内,阻抗在648.30~828.90Ω之间,电极植入深度6~11 mm最合适,穿孔风险小,且能较大概率成功夺获左束支,起搏参数满意,起搏QRS波时限较窄。在术中、术后48 h及12个月随访期间内,患者均未出现电极穿孔、血栓栓塞、心脏填塞、感染、导线脱位等并发症。结论:左束支区域起搏是一种安全可行的起搏方式。在左束支区域起搏时,V_(1)导联r’波振幅在一定合适范围内,并结合阻抗变化可指导左束支区域起搏,有助于降低电极穿孔的风险。

心律失常与起搏领域临床研究2023年度进展

回顾2023年心律失常领域重要临床试验,涉及心房颤动(房颤)、起搏等方面。CIRDADOSE研究及EARLY-AF研究均肯定冷冻球囊消融治疗房颤疗效,减慢房颤进展。MANIFEST-PF研究回顾房颤脉冲场消融的成功率及安全性,在ADVENT研究中再次证实其安全性和有效性不劣于传统热消融。在左束支区域起搏(LBBAP)研究中,与双心室起搏(BVP)相比,LBBAP降低持续性室性心动过速(VT)/心室颤动(VF)和新发房颤发生率。对于起搏比例高且射血分数降低的起搏器或植入式心律转复除颤器(ICD)患者,BUDAPEST CRT升级研究肯定了其升级到心脏再同步除颤器(CRT-D)的明确获益。DANPACEⅡ研究显示窦房结功能障碍患者的心房起搏最小化并不能降低房颤的发生率。IDE研究显示Aveir DR双腔无导线起搏器术后3个月安全性良好,可提供可靠的心房起搏和房室同步。iSUSI研究是对皮下植入式心律转复除颤器的注册研究,发现心力衰竭和非心力衰竭患者不恰当和恰当电击率相似。

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.

Comparison of Chinese LBs and English RBs

As English and Chinese belong to different language families,the left and right branching structures in the two languages are both similar and different.Generally speaking,Chinese has a predominance of left-branching structures and English has a predominance of right-branching structures.That is to say,Chinese is used to using left branches in its expressions,while English is used to using right branches in its expressions.