A Continuous Pacing and Recording Technique for Differentiating Left Bundle Branch Pacing From Left Ventricular Septal Pacing: Electrophysiologic Evidence From an Intrapatient-Controlled Study

BackgroundLeft bundle branch pacing (LBBP) is a promising approach for achieving near-physiologic pacing. However, differentiating LBBP from left ventricular septal endocardial pacing (LVS(e)P) remains a challenge. This study aimed to establish a simple and effective method for differentiating LBBP from LVS(e)P and to evaluate their electrophysiologic characteristics.MethodsLBBP, using continuous uninterrupted pacing and real-time monitoring of electrocardiograms along with intracardiac electrograms, was performed in 97 consecutive patients. We evaluated the electrophysiologic characteristics observed during LBBP using 6 modalities: right ventricular septal pacing (RVSP), intraventricular septal pacing (IVSP 1 and 2), LVS(e)P, nonselective LBBP (NSLBBP), and selective LBBP (SLBBP).ResultsOf the 97 patients, 87 (89.7%) met the criteria (abrupt change in paced QRS morphology with a transition from Qr to QR/qR in lead V1 and shortening of stimulus to V6 R-wave peak time [Stim-V6RWPT] of ≥ 10 ms with constant output while rather than after lead screwing) for nonselective left bundle branch (LBB) capture. Selective LBB capture was observed in 82 patients (84.5%). The Stim-V6RWPT of NSLBBP and SLBBP were significantly shorter than LVS(e)P (respectively, 67.1 ± 8.7 ms, 67.0 ± 9.3 ms, and 82.1 ± 10.9 ms). Stim-QRSend was the narrowest in IVSP2 (136.6 ± 15.2 ms) instead of NSLBBP (140.0 ± 17.1 ms).ConclusionsThe uninterrupted pacing technique for differentiating LBBP from LVS(e)P in the same group of patients is feasible. Electrophysiologic evidence from our intrapatient-controlled study shows that LBBP and LVS(e)P differ in ventricular electrical synchronization.     

左束支起搏心电图的特点观察

目的通过比较自身心律、左束支起搏、右室心尖部或右室流出道起搏时心电图的形态和QRS波群时限等,找寻左束支起搏心电图的特征表现。方法选取拟行左束支起搏42例患者,记录标准12导联体表心电图,通过测量,分别比较自身心律、左束支起搏及右室心尖部/右室流出道起搏时QRS波群时限、电轴、形态及ST段的差异。结果自身心律与左束支起搏相比,QRS波群时限无统计学差异(P=0. 49),但与右室心尖部/右室流出道起搏相比,具有显著差异(P <0. 000)。左束支起搏组,V1导联呈特征性"M"或"r SR"的比例为76. 19%;a VR导联亦可呈特征性"M"或"r SR"表现,比例为78. 57%。对于自身心律为右束支阻滞者,左束支区域起搏仅V1导联呈"M"或"r SR",a VR导联呈QS型,而无特征性"M"或"r SR"表现。与经典的右束支阻滞心电图比较:左束支起搏ST段和T波改变无规律性。结论左束支起搏心电图QRS波群时限和电轴与自身心律相比无显著差别,V1及a VR导联均可见特征性"M"或"r SR"表现,右束支阻滞患者仅V1导联呈特征性表现,但依靠心电图的特征性"M"或"r SR"改变判断起搏位点有局限性。     

Left bundle branch pacing: A comprehensive review

Cardiac pacing is the only effective therapy for patients with symptomatic bradyarrhythmia. Traditional right ventricular apical pacing causes electrical and mechanical dyssynchrony resulting in left ventricular dysfunction, recurrent heart failure, and atrial arrhythmias. Physiological pacing activates the normal cardiac conduction, thereby providing synchronized contraction of ventricles. Though His bundle pacing (HBP) acts as an ideal physiological pacing modality, it is technically challenging and associated with troubleshooting issues during follow‐up. Left bundle branch pacing (LBBP) has been suggested as an effective alternative to overcome the limitations of HBP as it provides low and stable pacing threshold, lead stability, and correction of distal conduction system disease. This paper will focus on the implantation technique, troubleshooting, clinical implications, and a review of published literature of LBBP.     

Left Bundle Branch Pacing for Cardiac Resynchronization Therapy: Nonrandomized On-Treatment Comparison With His Bundle Pacing and Biventricular Pacing

BackgroundLeft bundle branch pacing (LBBP) is a novel method for delivering cardiac resynchronization therapy (CRT). We compared on-treatment outcomes with His bundle pacing (HBP) and biventricular pacing (BVP) in this nonrandomized observational study.MethodsConsecutive patients with left-ventricular ejection fraction (LVEF) ≤ 40% and typical left bundle branch block (LBBB) referred for CRT received BVP, HBP, or LBBP. QRS duration, pacing threshold, LVEF, and New York Heart Association (NYHA) class were assessed.ResultsOne hundred thirty-seven patients were recruited: 49 HBP, 32 LBBP, and 54 BVP; 2 did not receive CRT. The majority of patients had nonischemic cardiomyopathy. Mean paced QRS duration was 100.7 ± 15.3 ms, 110.8 ± 11.1 ms, and 135.4 ± 20.2 ms during HBP, LBBP, and BVP, respectively. HBP and LBBP demonstrated a similar absolute increase (Δ) in LVEF (+23.9% vs +24%, P = 0.977) and rate of normalized final LVEF (74.4% vs 70.0%, P = 0.881) at 1-year follow-up. This was significantly higher than in the BVP group (Δ LVEF +16.7% and 44.9% rate of normalized final LVEF, P < 0.005). HBP and LBBP also demonstrated greater improvements in NYHA class compared with BVP. LBBP was associated with higher R-wave amplitude (11.2 ± 5.1 mV vs 3.8 ± 1.9 mV, P < 0.001) and lower pacing threshold (0.49 ± 0.13 V/0.5 ms vs 1.35 ± 0.73 V/0.5 ms, P < 0.001) compared with HBP.ConclusionLBBP appears to be a promising method for delivering CRT. We observed similar improvements in symptoms and LV function with LBBP and HBP. These improvements were significantly greater than those seen in patients treated with BVP in this nonrandomized study. These promising findings justify further investigation with randomized trials.     

Feasibility,safety and outcomes of left bundle branch pacing in octogenarians

ObjectivesLeft bundle branch pacing (LBBP) provides physiological pacing at low and stable threshold. The safety and efficacy of LBBP in elderly population is unknown. Our study was designed to assess the safety, efficacy and electrophysiological parameters of LBBP in octogenarian (≥80 years) population.ResultsLBBP was successful in 10 out of 11 patients. Mean age 82.1 ± 2.5 yrs. Follow up duration 7.7 months(range4–10). Indication for pacing included atrioventricular (AV) block 5 patients, Left bundle branch block (LBBB) with low ejection fraction (EF) 4 patients, sinus node dysfunction in 1. QRS duration reduced from 145.9 ± 27.7ms to 107.1 ± 9.5ms (p value0.00001) LV ejection fraction increased from 47.6% to 58.4% after LBBP (p value0.017). Pacing threshold was 0.58 ± 0.22 V and sensed R wave 17.35 ± 6.5 mV and it remained stable during follow up. LBBB with low EF patients also showed similar reduction in QRS duration along with improvement in LVEF.ConclusionLBBP is a safe and effective strategy (91% acute success) of physiological pacing in elderly patients. LBBP also provided effective resynchronization therapy in our small group of elderly patients. The pacing parameters remained stable over a period of 10 months follow up.     

Assessment of ventricular mechanical synchronization after left bundle branch pacing using 2-D speckle tracking echocardiography

BackgroundThe left bundle branch pacing (LBBP) makes the ventricular depolarization closer to the physiological state and shortens QRS duration. The purpose of this study is to explore the ventricular systolic mechanical synchronization after LBBP in comparison with traditional right ventricular pacing (RVP) using two‐dimensional strain echocardiography (2D‐STE).MethodsThirty‐two patients who received LBBP (n = 16) or RVP (n = 16) from October 2018 to October 2019 and met the inclusion criteria were included in this retrospective study. Electrocardiogram (ECG) characteristics, pacing parameters, pacing sites, and safety events were assessed before and after implantation. Acquisition and analysis of ventricular systolic synchronization were implemented using 2D‐STE.ResultsIn RVP group, ECG showed left bundle branch block patterns. At LBBP, QRS morphology was in the form of right bundle branch block, and QRS durations were significantly shorter than that of the RVP QRS (109.38 ± 12.89 vs 149.38 \± 19.40 ms, P < .001). Both the maximum time differences (TD) and SDs of the 18‐segments systolic time to peak systolic strain were significantly shorter under LBBP than under RVP (TD, 66.62 ± 37.2 vs 148.62 ± 43.67 ms, P < .01; SD, 21.80 ± 12.13 vs 52.70 ± 17.72 ms, P < .01), indicating that LBBP could provide better left ventricular mechanical synchronization. Left and right ventricular pre‐ejection period difference was significantly longer in RVP group than in LBBP group (10.23 ± 3.07 vs 39.94 ± 14.81 ms, P < .05), indicating left and right ventricular contraction synchronization in LBBP group being better than in RVP group.ConclusionLBBP is able to provide a physiologic ventricular activation pattern, which results in ventricular mechanical contraction synchronization.     

左束支起搏对合并右束支传导阻滞患者的心电学影响

目的探讨左束支起搏对症状性心动过缓合并右束支传导阻滞患者的心电学影响。 方法连续纳入2019年1月1日至2021年12月31日因症状性心动过缓合并完全性右束支传导阻滞并在厦门大学附属心血管病医院心内科拟行左束支起搏的患者,记录标准12导联体表心电图。比较左束支起搏术前与术后V₁导联QRS波形态、QRS时限、右心室延迟激动时间（dRVAT）、左心室达峰时间（LVAT）及心室间延迟时间（IVD）的差异。 结果共入选53例患者,年龄（72.15±9.39）岁,男34例。其中46例（86.79%,46/53）成功完成左束支起搏。术前V₁导联以rsR’型为主38例（38/46,83%）,术后QRS形态以Qr型为主29例（29/46,63%）。左束支起搏可以显著缩短QRS时限［（149.09±12.81）ms对（112.46±9.64）ms,P<0.001）］,其中35例（76.08%,35/46）患者的QRS时限完全纠正,10例（21.73%,10/46）部分纠正,1例（2.17%,1/46）未纠正;IVD显著缩短［（58.28±12.54）ms对（34.34±8.87）ms,P<0.001］;但在dRVAT方面左束支起搏术前与术后差异无统计学意义［（100.47±12.40）ms对（100.86±10.57）ms,P=0.955］。与术前相比,左束支起搏延长LVAT［（42.46±6.95）ms对（66.53±10.83）ms,P<0.001］。 结论左束支起搏可显著缩短完全性右束支传导阻滞患者的QRS时限,并改善其心室间电学同步性,产生以Qr型为主的起搏后QRS波形态。     

实时三维超声心动图评估左束支起搏术对左心室同步性及心室功能的影响

目的 实时三维超声心动图（RT-3DE）评估左束支区域起搏（LBBP）与右心室流出道起搏（RVOP）手术前后患者左右心室收缩功能及左心室同步性。方法 纳入西安交通大学第二附属医院永久起搏器置入患者56例,根据不同术式分为LBBP组（n=30）和RVOP组（n=26）。应用三维超声心动图获取两组患者术前及术后左右心室收缩功能以及左室同步性参数,比较两组患者手术前后及两组之间的差异。结果 术后6个月随访,RVOP组LVGLS较术前降低（P<0.05）;患者左心室16节段同步性参数Tmsv16-SD、Tmsv16-SD%、Tmsv16-Dif、Tmsv16-Dif%较术前均明显增大（均P<0.01）;右心室收缩功能减低,TAPSE(P<0.01)、3D-RVEF(P<0.05)较术前下降。术后6个月随访,LBBP组LV-GLS值高于RVOP组（P<0.05）,左心室16节段同步性参数Tmsv16-SD(P<0.05)、Tmsv16-SD%(P<0.01)、Tmsv16-Dif(P<0.01)、Tmsv16-Dif%(P<0.05)均明显减...     

左束支起搏患者心脏机械同步性的早期评估

目的:通过超声心动图评估左束支起搏患者的心脏机械同步性的早期改变.方法:选取2019年5月至2019年12月因二度Ⅱ型及以上房室阻滞在成都市第三人民医院心内科住院并顺利行左束支起搏术(LBBP)的患者21例(LBBP组),同时选取同期行右心室流出道起搏术(RVOTP)的二度Ⅱ型及以上房室阻滞患者23例(RVOTP组)....     

Permanent left bundle branch area pacing in a child with a third‐degree atrioventricular block: A case report

Permanent left bundle branch area pacing (LBBP) is a promising physiological pacing technique that has emerged in recent years. However, LBBP is almost exclusively clinically applied in adult patients. The feasibility and safety of the use of LBBP in children have not been well‐assessed. Here, we report the case of a 6‐year‐old child with a third‐degree atrioventricular block after surgical aortic valve replacement who successfully received a permanent LBBP.     

Safety and efficacy of left bundle branch pacing in comparison with conventional right ventricular pacing: A systematic review and 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.     

Application of permanent left bundle branch pacing inpatients with bradycardia after cardiac surgery

正may be a preferred pacing strategy for patients after cardiac surgery.[S Chin J Cardiol 2021;22(1):13-20]     

右房左室起搏治疗慢性心力衰竭伴室内传导阻滞患者的初步临床观察

观察右房 左室起搏治疗慢性心力衰竭 (简称心衰 )的临床效果。选择 1 6例充血性心衰患者 (NYHA分级Ⅲ Ⅳ级 ) ,男 1 0例、女 6例 ,年龄 6 8.4± 6岁 ;均为窦性心律 ,合并有Ⅰ度房室阻滞 ,完全性左束支阻滞。按安置起搏器的模式分为右房 左室起搏治疗组 (LV组 ,n =6 ) ,右房双室起搏治疗组 (BiV组 ,n =1 0 )。左室起搏电极分别放置于心大静脉左室侧后分支 9例 ,心大静脉左室后分支 7例。观察起搏治疗前后左室心功能参数、6min步行距离、左室壁运动的同步性及体表心电图的变化。结果 :BiV组左室射血分数 (LVEF)由术前的 0 .2 3提高至 0 .31 (P <0 .0 0 1 ) ;在LV组LVEF由术前的 0 .2 4提高至 0 .33(P <0 .0 0 1 ) ;左室舒张末期容积指数在二组分别由术前的 1 4 9± 5 1ml/m2 和 1 5 3±5 3ml/m2 下降至 1 1 6± 38ml/m2 和 1 2 1± 4 1ml/m2 (P均 <0 .0 0 1 ) ;室间隔与左室后壁运动的延迟时间在二组分别由术前的 1 95± 94ms和 1 97± 89ms下降至 1 7± 6 0ms及 1 6± 5 6ms(P均 <0 .0 0 1 )。 6min步行距离则分别由术前的4 0 3± 5 3m和 4 0 1± 5 9m提高至 4 4 1± 6 2m和 4 4 2± 6 7m(P均 <0 .0 5 )。结论 :初步临床观察提示右房 左室起搏治疗与右房双室起搏治疗相比 ,同样可有效地改善慢性心衰?     

Best site on right ventricle for open-chest biventricular pacing

Cardiac resynchronization therapy is effective in patients with a low ejection fraction and left bundle branch block, but 20%-30% do not respond despite selection of the optimal site for pacing on the left ventricle. We investigated whether optimizing the site for placement of the pacing lead on the right ventricle could further improve left ventricular function during cardiac resynchronization in 19 patients (mean age, 63 +/- 5 years) undergoing coronary artery bypass with post-ischemic dilated myocardiopathy (ejection fraction, 25.8% +/- 2%) and left bundle branch block. The hemodynamic response to pacing was tested with the right ventricular lead positioned at the interventricular septum, atrioventricular junction, acute margin, and the pulmonary trunk. Biventricular stimulation improved left ventricular function. When the right ventricular lead was sited at the interventricular septum, a significant improvement in all hemodynamic parameters compared to the other sites was obtained. Biventricular pacing is important to optimize cardiac resynchronization. Although further studies are needed to confirm these findings, accurate lead placement is recommended for cardiac resynchronization therapy in patients with poor cardiac function and left bundle branch block.     

左束支起搏的心脏电学和机械同步性及中远期导线稳定性研究

目的:本研究观察左束支起搏(LBBP)的心脏电学和机械同步性以及中远期导线参数稳定性,旨在评估其生理性以及可靠性。方法:连续入选2018年1月25日至2019年1月25日就诊我院符合起搏适应证并成功施行LBBP的患者96例,详细记录患者的临床资料以及术中导线单、双极参数。于术后3天、1个月、3个月、6个月以及12个月随访,测试导线单、双极参数并记录随访期内并发症。筛选其中诊断病窦综合征(SSS)伴基线QRS时限正常的患者36例进行心室同步性分析。起搏器程控分为两种状态:(1)AAI模式:起搏器工作方式为心房起搏-心室感知,保证激动沿自身传导束下传心室;(2)DDD模式且房室间期相似文献   

二维斑点追踪成像联合组织多普勒成像技术评价左束支起搏术后早期室间同步性

目的 采用二维斑点追踪成像联合组织多普勒成像技术对左束支起搏术后早期室间同步性进行评价,比较两种方法评价室间同步性的效果.方法 选取2019年5月—2020年5月于成都市第三人民医院心内科行左束支起搏的患者30例作为病例组,行右室流出道起搏的患者24例作为对照组.术后1个月行经胸超声心动图检查,采集至少三个心动周期的心...     

Effect of scar and His–Purkinje and myocardium conduction on response to conduction system pacing

Introduction

Conduction system pacing (CSP), in the form of His bundle pacing (HBP) or left bundle branch pacing (LBBP), is emerging as a valuable cardiac resynchronization therapy (CRT) delivery method. However, patient selection and therapy personalization for CSP delivery remain poorly characterized. We aim to compare pacing-induced electrical synchrony during CRT, HBP, LBBP, HBP with left ventricular (LV) epicardial lead (His-optimized CRT [HOT-CRT]), and LBBP with LV epicardial lead (LBBP-optimized CRT [LOT-CRT]) in patients with different conduction disease presentations using computational modeling.

Methods

We simulated ventricular activation on 24 four-chamber heart geometries, including His–Purkinje systems with proximal left bundle branch block (LBBB). We simulated septal scar, LV lateral wall scar, and mild and severe myocardium and LV His–Purkinje system conduction disease by decreasing the conduction velocity (CV) down to 70% and 35% of the healthy CV. Electrical synchrony was measured by the shortest interval to activate 90% of the ventricles (90% of biventricular activation time [BIVAT-90]).

Results

Severe LV His–Purkinje conduction disease favored CRT (BIVAT-90: HBP 101.5 ± 7.8 ms vs. CRT 93.0 ± 8.9 ms, p < .05), with additional electrical synchrony induced by HOT-CRT (87.6 ± 6.7 ms, p < .05) and LOT-CRT (73.9 ± 7.6 ms, p < .05). Patients with slow myocardium CV benefit more from CSP compared to CRT (BIVAT-90: CRT 134.5 ± 24.1 ms; HBP 97.1 ± 9.9 ms, p < .01; LBBP: 101.5 ± 10.7 ms, p < .01). Septal but not lateral wall scar made CSP ineffective, while CRT was able to resynchronize the ventricles in the presence of septal scar (BIVAT-90: baseline 119.1 ± 10.8 ms vs. CRT 85.1 ± 14.9 ms, p < .01).

Conclusion

Severe LV His–Purkinje conduction disease attenuates the benefits of CSP, with additional improvements achieved with HOT-CRT and LOT-CRT. Septal but not lateral wall scars make CSP ineffective.     

Incidence of reentry with an excitable gap in ventricular tachycardia: a prospective evaluation utilizing transient entrainment

The demonstration of transient entrainment has been proposed as evidence of reentry, with an excitable gap as the probable mechanism of tachycardia. A prospective series of 27 consecutive patients with sustained ventricular tachycardia induced by programmed electrical stimulation was studied to determine the frequency with which transient entrainment can be demonstrated and to define the optimal location of pacing and recording electrodes. In all patients, electrodes for pacing and recording were placed in both the left and right ventricles during electrophysiologic study. Among the 19 patients in whom the response to rapid pacing could be evaluated (25 episodes of ventricular tachycardia), transient entrainment was demonstrated in 79% (76% of episodes). Ten of 12 episodes of ventricular tachycardia with a left bundle branch block QRS configuration in lead V1 and 9 of 13 episodes with a right bundle branch block QRS configuration could be transiently entrained (p = NS). Transient entrainment was demonstrated for 8 of 11 episodes of ventricular tachycardia with a left bundle branch block configuration during pacing from the left ventricle, but for only 2 of 10 episodes during pacing from the right ventricular apex (p less than 0.05). Conversely, 9 of 13 episodes of ventricular tachycardia with a right bundle branch block configuration were transiently entrained during pacing from the right ventricular apex, but 0 of 10 episodes were transiently entrained by left ventricular pacing (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

The electrocardiogram characteristics and pacing parameters of permanent left bundle branch pacing: a systematic review and meta-analysis

Journal of Interventional Cardiac Electrophysiology - Recent advances in conduction system pacing have led to the use of left bundle branch pacing (LBBP), which has potential advantages over His...     

Right subclavian vein approach for selective left bundle branch pacing: A case report

We reported a 65-year-old man with symptomatic bradycardia caused by chronic atrial fibrillation who underwent pacemaker implantation by left bundle branch pacing (LBBP) via right subclavian vein (RSV) approach. A tricuspid valve annulus (TVA) angiography was performed, and a different connecting cable that can monitor electrocardiograms (ECG) and intracardiac electrograms (EGM) in real time was used during the process. By TVA angiography, we could easily find the ideal location of LBBP; a new connecting cable helped us avoid perforation and guide effective endpoint without the need to stop pacing. The case showed that it was feasible and safe to use the new method for LBBP through RSV route.