真性完全性左束支阻滞与心脏再同步化治疗超反应的研究进展

真性完全性左束支阻滞作为一个新概念被提出,不仅促进了心电学的发展,而且也丰富了心脏再同步化治疗心力衰竭的内容,并成为慢性心力衰竭伴真性完全性左束支阻滞的患者对心脏再同步化治疗获超反应的一个新的预测因子.     

合并符合新诊断标准的左束支阻滞的慢性心力衰竭患者应用心脏再同步化治疗的疗效分析

目的:分析慢性心力衰竭患者合并符合新诊断标准的左束支阻滞(LBBB)(真性LBBB)能否从心脏再同步化治疗(CRT)中更能获益。方法:研究入选2005-06至2013-05接受CRT的19例患者,依据术前体表心电图QRS波的形态,符合新诊断标准即为真性LBBB组(n=13),符合传统诊断标准即为假性LBBB组(n=6);比较所有入选患者CRT术前与术后左心室射血分数(LVEF)、左心室舒张末内径(LVEDD)、QRS波时限(QRSd)及心室间机械延迟时间(IVMD);同时比较两组患者术后LVEF、LVEDD、QRSd、IVMD、16节段达最小收缩末容积时间标准差(Tmsv16-SD)及16节段达最小收缩末容积时间的最大差值(Tmsv16-Dif)有无差异。结果:两组患者在CRT术后的LVEF、LVEDD、IVMD及QRSd均较术前有明显的改善;而且与假性LBBB组比,真性LBBB组的LVEDD[(5.95±0.72)mm vs(7.13±0.78)mm,P0.01]、IVMD[(22.45±8.00)ms vs(27.63±13.09)ms,P0.01]及QRSd[(140.38±5.80)ms vs(153.68±14.38)ms,P0.01]改善更明显;术后两组患者的Tmsv16-SD、Tmsv16-Dif及LVEF的差异均无统计学意义。结论:合并真性LBBB和假性LBBB的心力衰竭患者均能从CRT中获益,合并真性LBBB的心力衰竭患者获益更明显。     

束支阻滞类型对心脏再同步治疗效果的影响

目的 探讨不同类型束支阻滞对心脏再同步治疗(CRT)效果的影响.方法 159例难治性心力衰竭患者接受CRT治疗,其中6例已植入永久起搏器,其余153例患者根据体表心电图QRS波形态分为左束支阻滞(LBBB)、右束支阻滞(RBBB)、非特异性室内阻滞(IVCD)、右束支伴左侧分支阻滞(RBBB伴LHB)及室内伴左侧分支阻滞(IVCD伴LHB)5组,比较植入术前及术后6个月心功能(NYHA分级)、QRS时限、左心室射血分数(LVEF)、左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)等指标的差异.结果 153例患者年龄21～ 84(61.43±12.54)岁,其中男118例,女35例.LBBB组治疗后心功能(3.13±0.55对2.84±0.65)、QRS时限[173.37±28.54)ms对(156.29±22.25)ms]及LVEF[(0.31±0.07)对(0.39±0.09)]、LVEDD[(73.09± 10.81) mm对(68.18± 11.36) mm]、LVESD[(61.38±11.60)mm对(55.20±13.25)mm]等均明显改善(P＜0.01).RBBB组治疗后各项指标未得到显著改善(P＞0.05),IVCD组与RBBB伴LHB组治疗后LVEF显著提高,LVEDD缩小(P＜0.05),而IVCD伴LHB组除QRS时限外,心功能、LVEF、LVEDD、LVESD等指标均得以改善(P＜0.05).此外,RBBB组与IVCD组超声心动图指标的改变不及LBBB组(P＜0.05),而RBBB伴LHB组及IVCD组超声心动图指标改善程度与LBBB组相近(P＞0.05).应用Cox回归分析显示LBBB者较其他束支阻滞类型生存期长(风险比0.30,95％可信区间0.12～0.77,P＜0.01).结论 LBBB者对CRT的反应性优于RBBB者,IVCD者疗效可能介于两者之间,而RBBB伴LHB或IVCD者疗效优于单纯RBBB或IVCD者.     

真性左束支传导阻滞预示心脏再同步化治疗超应答发生

目的研究新定义的真性左束支传导阻滞对慢性心力衰竭患者心脏再同步化治疗(CRT)的应答率是否提高。方法回顾性分析在兰州大学第一医院行CRT治疗患者的临床资料,分析术前心电图不同形态QRS波与预后的关系。结果 62例患者中,真性左束支传导阻滞组24例,假性左束支传导阻滞组16例和非左束支传导阻滞组22例,经(49.1±48.5)个月随访,CRT术后患者左室射血分数和NYHA心功能分级显著改善。术前心电图QRS波形态与CRT患者全因死亡和因心力衰竭再入院率无关。多变量回归分析表明真性左束支传导阻滞和年龄是CRT后发生超应答的强力预测因子。结论真性左束支传导阻滞是CRT术后发生超应答的强力预测因子。     

伴右束支传导阻滞的心力衰竭患者行心脏再同步化治疗疗效欠佳的相关因素分析

目的分析伴右束支传导阻滞(RBBB)者心脏再同步化治疗(CRT)疗效欠佳的可能影响因素。方法 209例接受CRT的患者,根据其术前QRS波形态分为左束支传导阻滞(LBBB)与RBBB组,比较两组基线临床特征和CRT术后6个月临床心功能、QRS波时限(QRSd)、左室射血分数(LVEF)等心脏超声指标的差异。剔除缺血性心肌病、重度肺动脉高压和QRSd150 ms的病例后,再次比较两组间CRT疗效差异。结果与LBBB组比较,RBBB组缺血性心肌病占比较高(26.0%vs 11.3%),肺动脉收缩压亦高[(50.14±17.10)mmHg vs(44.27±15.16)mmHg],QRSd则较窄[(152.36±26.84)ms vs(162.92±29.67)ms](P0.05)。CRT术后6个月,LBBB组临床心功能改善、LVEF的提高均显著优于RBBB组(P0.05)。而将缺血性心肌病、重度肺动脉高压和QRSd150ms的病例剔除后,CRT术后两组间各项指标均无差异。结论缺血性心肌病、重度肺动脉高压、相对较窄的QRS波可能是RBBB者CRT疗效欠佳的原因。     

右束支阻滞患者心脏再同步治疗疗效分析

目的 回顾分析阜外心血管病医院心律失常中心合并右束支阻滞(RBBB)的心力衰竭患者心脏再同步治疗(CRT)疗效.方法 本中心自2008年1月至2010年12月植入CRT-P/D的合并RBBB的心力衰竭患者,接受常规每3～6个月门诊随访,随访内容包括心功能(NYHA分级)、6 min步行距离、Minnesota生活质量评分、超声心动图及程控等指标.结果 共7例合并RBBB心力衰竭患者植入CRT-P/D,其中男6例,女1例,年龄19 ～74(57±19)岁.随访0.3～43.0(17.6±16.7)个月.随访期间发生心力衰竭住院事件7次,3例患者因心力衰竭加重死亡.6例患者为CRT无反应者,1例为CRT反应者.结论 合并RBBB的心力衰竭患者CRT无明显获益.     

心脏再同步化治疗的认识和存在问题

心脏再同步化治疗(cardiac resynchronization therapy,CRT)是有效治疗心力衰竭的非药物措施。CRT主要适应证为NYHA分级Ⅱ～Ⅳ级、窦性心律和完全性左束支传导阻滞患者,也适用于部分非左束支传导患者。尽管CRT在多数患者中可明显改善患者预后,但在部分患者中效果不佳,表现为CRT无反应者。如何减少CRT无反应者比例是CRT临床应用中的重要问题。该文对CRT治疗心力衰竭机制、目前主要临床研究结果和CRT无反应的可能原因及解决方案作一综述。     

左束支阻滞性心肌病

长期的真性左束支阻滞可引起左室扩大、心功能进行性下降,进而发展为伴有心功能不全的心肌病。这种左束支阻滞性心肌病的发病机制尚不明确,可能与左束支阻滞所致的电-机械活动失同步有关。该病的临床诊断过程与获得性心肌病一致,关键是识别真性左束支阻滞。心脏再同步化治疗能有效逆转左束支阻滞性心肌病。     

心力衰竭合并右束支传导阻滞患者心脏再同步化治疗现状

心脏再同步化治疗(CRT)已成为中重度心力衰竭患者的一线治疗方法。然而,CRT治疗对于合并右束支传导阻滞(RBBB)的患者疗效不佳。这可能与RBBB患者心脏病变更为严重有关。不过,RBBB患者也可能存在左室激动延迟,因此有可能从CRT治疗中获益。应用临床和超声学指标筛选CRT植入者有助于改善其反应率。     

心力衰竭患者心脏再同步化治疗最新进展

心力衰竭指心脏结构或功能性原因导致心室充盈和/或射血功能受损而引起的一组综合征。心脏再同步化治疗(CRT)是心力衰竭中的一种器械治疗方式,旨在通过双心室起搏改善心室收缩的不同步,进而提高射血分数,改善心功能。自20世纪90年代开始CRT应用于临床,大量临床研究证实了其安全性及有效性,其适应证在不断扩大,但CRT与心脏再同步化治疗除颤器的选择在临床上一直存在疑问,且近几年希氏束-浦肯野系统起搏开始应用于CRT中,使这一领域出现新的憧憬。现就目前CRT的研究现状,其与心脏再同步化治疗除颤器和希氏束-浦肯野系统起搏的抉择进行综述,给临床工作提出一定的指导意义。     

真假性左束支阻滞心电图的鉴别

左束支阻滞(left bundle branch block,LBBB)是不良心脏事件的独立预测因素,与不良预后密切相关.然而,心电图呈LBBB样并不意味着左束支传导功能完全阻断(真性LBBB),尚存在左束支传导延缓、室内阻滞等假性LBBB样图形(假性LBBB).由于真假性LBBB的病理生理学、治疗方式及预后明显不同,...     

Remarkable response to cardiac resynchronization therapy via left bundle branch pacing in patients with true left bundle branch block

BackgroundLeft bundle branch pacing (LBBP) has been suggested as an alternative means to deliver cardiac resynchronization therapy (CRT).HypothesisLBBP may deliver resynchronization therapy along with an advantage over traditional biventricular (BiV) pacing in clinical outcomes.MethodsHeart failure patients who presented LBBB morphology according to Strauss''s criteria and received successful CRT procedure were enrolled in the present study. Propensity score matching was applied to match patients into LBBP‐CRT group and BiV‐CRT group. Then, the electrographic data, the echocardiographic data and New York heart association (NYHA) class were compared between the groups.ResultsTwenty‐one patients with successful LBBP procedure and another 21 matched patients with successful BiV‐CRT procedure were finally enrolled in the study. The QRS duration (QRSd) was narrowed from 167.7 ± 14.9 ms to 111.7 ± 12.3 ms (P < .0001) in the LBBP‐CRT group and from 163.6 ± 13.8 ms to 130.1 ± 14.0 ms (P < .0001) in the BiV‐CRT group. A trend toward better left ventricular ejection fraction (LVEF) was recorded in the LBBP‐CRT group (50.9 ± 10.7% vs 44.4 ± 13.3%, P = .12) compared to that in the BiV‐CRT group at the 6‐month follow‐up. A trend toward better echocardiographic response was documented in patients receiving LBBP‐CRT procedure (90.5% vs 80.9%, P = .43) and more super CRT response was documented in the LBBP‐CRT group (80.9% vs 57.1%, P = .09) compared to that in the BiV‐CRT group.ConclusionsLBBP‐CRT can dramatically improve the electrical synchrony in heart failure patients with LBBB. Meanwhile, compared with the traditional BiV‐CRT, it has a tendency to significantly improve LVEF and enhance the NYHA cardiac function scores.     

Defining left bundle branch block in the era of cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) has emerged as an attractive intervention to improve left ventricular mechanical function by changing the sequence of electrical activation. Unfortunately, many patients receiving CRT do not benefit but are subjected to device complications and costs. Thus, there is a need for better selection criteria. Current criteria for CRT eligibility include a QRS duration ≥ 120 ms. However, QRS morphology is not considered, although it can indicate the cause of delayed conduction. Recent studies have suggested that only patients with left bundle branch block (LBBB) benefit from CRT, and not patients with right bundle branch block or nonspecific intraventricular conduction delay. The authors review the pathophysiologic and clinical evidence supporting why only patients with complete LBBB benefit from CRT. Furthermore, they review how the threshold of 120 ms to define LBBB was derived subjectively at a time when criteria for LBBB and right bundle branch block were mistakenly reversed. Three key studies over the past 65 years have suggested that 1/3 of patients diagnosed with LBBB by conventional electrocardiographic criteria may not have true complete LBBB, but likely have a combination of left ventricular hypertrophy and left anterior fascicular block. On the basis of additional insights from computer simulations, the investigators propose stricter criteria for complete LBBB that include a QRS duration ≥ 140 ms for men and ≥ 130 ms for women, along with mid-QRS notching or slurring in ≥ 2 contiguous leads. Further studies are needed to reinvestigate the electrocardiographic criteria for complete LBBB and the implications of these criteria for selecting patients for CRT.     

Differentiation between left bundle branch block and left ventricular hypertrophy: Implications for cardiac resynchronization therapy

Recent clinical trials have demonstrated that cardiac resynchronization therapy (CRT) reduces heart failure hospitalizations and mortality in patients with complete left bundle branch block (LBBB), but potentially not those with right bundle branch block or nonspecific LV conduction delay, such as that due to LV hypertrophy (LVH). Furthermore, endocardial mapping and simulation studies have suggested that one-third of patients diagnosed with LBBB by conventional electrocardiographic criteria are misdiagnosed, and these patients likely have a combination of LVH, LV chamber dilatation and delayed initiation of LV activation (incomplete LBBB). Increase in LV size due to hypertrophy/dilatation and slowed intramyocardial conduction velocity prolong QRS duration in patients with LVH, which can frequently go above the QRS duration threshold of 120 ms conventionally used to diagnose LBBB. New strict criteria for diagnosing complete LBBB have been proposed that utilize longer QRS duration thresholds (130 ms in women and 140 ms in men) and require the presence of mid-QRS notching/slurring in at least 2 of the leads I, aVL, V1, V2, V5 or V6. The emergence of CRT has led to an increased need to differentiate complete LBBB from LVH and other types of intraventricular conduction delay, which should be further studied.     

Hyperkalemic left bundle branch block and hyporeninemic hypoaldosteronism (hyperkalemic left bundle branch block)

A 70-year-old woman was admitted to the intensive coronary care unit with suspected myocardial infarction. During the follow-up period, the patient twice developed left bundle branch block, which was shown to be related to high serum potassium levels secondary to hyporeninemic hypoaldosteronism and moderate renal failure.