Cardiac resynchronization therapy by left bundle branch area pacing in patients with heart failure and left bundle branch block

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不同左束支阻滞型态的心力衰竭患者心脏再同步治疗效果比较

目的 验证符合左束支阻滞(LBBB)新诊断标准的慢性心力衰竭患者是否能从心脏再同步治疗(CRT)中更显著地获益.方法 入选2007年5月至2012年6月符合传统LBBB诊断标准且植入CRT患者,根据术前体表心电图形态分为“真性”LBBB组(真LBBB组:V1、V2导联负向波为主(QS或rS);V1、V2、V5、V6、I、aVL导联中至少有2个以上的导联QRS波中间有切迹或顿挫;QRS时限,男≥140 ms、女≥130ms)和“假性”LBBB组(假LBBB组:符合传统的LBBB标准,但尚未达到“真性”LBBB诊断标准,具体包括上述6个导联中仅有1个或没有导联出现切迹或者顿挫,QRS时限,男＜140 ms、女＜130 ms).术后定期随访,比较两组患者QRS时限、左心室舒张末期内径(LVEDD)、左心室射血分数(LVEF)及心功能(NYHA分级)变化.结果 共入选32例患者(男13例),真LBBB组23例,假LBBB组9例,术前两组患者间性别、年龄、基础疾病、LVEF及心功能等基本情况差异无统计学意义.术后随访显示真LBBB组较假LBBB组LVEF增加显著(0.39±0.11对0.27±0.07,P=0.006),LVEDD缩小明显[(6.3±1.0)cm对(7.6±1.0) cm,P=0.003],提示真LBBB组对CRT治疗反应更佳.结论 符合LBBB新诊断标准的慢性心力衰竭患者从CRT中更显著获益.     

Left ventricular‐only fusion pacing versus cardiac resynchronization therapy in heart failure patients: A randomized controlled trial

BackgroundIt is unclear whether clinical benefits of cardiac resynchronization can be achieved by pacing only the left ventricle.HypothesisWe aimed to compare the effect of a novel adaptive left ventricular‐only fusion pacing (LVP) on ventricular function with conventional biventricular pacing (BVP) in cardiac resynchronization therapy (CRT) indicated patients.MethodsThis prospective, randomized, multicenter study enrolled CRT‐indicated patients with PR interval ≤ 200 ms who were randomized in the adaptive LVP group (using the AdaptivCRT™ algorithm with intentional non‐capture right ventricular pacing) or the echocardiography‐optimized BVP group. Cardiac function and echocardiography were evaluated at baseline and follow‐ups. CRT super response was defined as two‐fold or more increase of left ventricular ejection fraction (LVEF) or final LVEF >45%, and LV end‐systolic volume (LVESV) decrease >15%, and New York Heart Association (NYHA) class improved by at least one level.ResultsSixty‐three patients were enrolled in the study (LVP = 34 vs. BVP = 29). At 6‐month follow‐up, significant improvements in LVEF, LVESV, and NYHA class were observed in both groups. The CRT super response rate was significantly higher in patients with high‐percentage adaptive LV‐only pacing in LVP group (68.4%) than in BVP group (36.4%, p = .04).ConclusionsAdaptive LV‐only pacing was comparable to BVP in improving cardiac function and clinical condition in CRT‐indicated patients. This finding raises the possibility that an adaptive LVP algorithm with appropriate right ventricular sensing to fuse with intrinsic right ventricular activation in a two‐lead (right atrium and left ventricle) device may provide clinical benefit in a subset of CRT patients with intact atrioventricular conduction.     

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.     

Cardiac resynchronization therapy: Dire need for targeted left ventricular lead placement and optimal device programming

Cardiac resynchronization therapy (CRT) effected via biventricular pacing has been established as prime therapy for heart failure patients of New York Heart Association functional class II, III and ambulatory IV, reduced left ventricular (LV) function, and a widened QRS complex. CRT has been shown to improve symptoms, LV function, hospitalization rates, and survival. In order to maximize the benefit from CRT and reduce the number of non-responders, consideration should be given to target the optimal site for LV lead implantation away from myocardial scar and close to the latest LV site activation; and also to appropriately program the device paying particular attention to optimal atrioventricular and interventricular intervals. We herein review current data related to both optimal LV lead placement and device programming and their effects on CRT clinical outcomes.     

On-treatment comparison between corrective His bundle pacing and biventricular pacing for cardiac resynchronization: A secondary analysis of the His-SYNC Pilot Trial

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Randomized prospective trial of atrioventricular delay programming for cardiac resynchronization therapy

OBJECTIVES: The purpose of this study was to determine if AV delay optimization with continuous-wave Doppler aortic velocity-time integral (VTI) is clinically superior to an empiric program in patients treated with cardiac resynchronization therapy (CRT) for severe heart failure. BACKGROUND: The impact of AV delay programming on clinical outcomes associated with CRT is unknown. METHODS: A randomized, prospective, single-blind clinical trial was performed to compare two methods of AV delay programming in 40 patients with severe heart failure referred for CRT. Patients were randomized to either an optimized AV delay determined by Doppler echocardiography (group 1, n = 20) or an empiric AV delay of 120 ms (group 2, n = 20) with both groups programmed in the atriosynchronous biventricular pacing (VDD) mode. Optimal AV delay was defined as the AV delay that yielded the largest aortic VTI at one of eight tested AV intervals (between 60 and 200 ms). New York Heart Association (NYHA) functional classification and quality-of-life (QOL) score were compared 3 months after randomization. RESULTS: Immediately after CRT initiation with AV delay programming, VTI improved by 4.0 +/- 1.7 cm vs 1.8 +/- 3.6 cm (P < .02), and ejection fraction (EF) increased by 7.8 +/- 6.2% vs 3.4 +/- 4.4% (P < .02) in group 1 vs group 2, respectively. After 3 months, NYHA classification improved by 1.0 +/- 0.5 vs 0.4 +/- 0.6 class points (P < .01), and QOL score improved by 23 +/- 13 versus 13 +/- 11 points (P < .03) for group 1 vs group 2, respectively. CONCLUSIONS: Echocardiography-guided AV delay optimization using the aortic Doppler VTI improves clinical outcomes at 3 months compared to an empiric AV delay program of 120 ms.     

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.     

Hisian pacing restores cardiac function

We report a 57-year-old male patient with dilated cardiomyopathy, NYHA function class III and complete left bundle branch block (CLBBB) who received cardiac resynchronization therapy using His-bundle pacing (HBP) when a left-ventricular lead could not be placed. In 10 months' follow up, his symptoms resolved rapidly, his QRS, left ventricular and left ventricular ejection fraction normalized. Recent reports support the conception that HBP may be an alternative or even better therapy for heart failure patients with CLBBB, especially if biventricular pacing is not feasible.     

Left ventricular pacing site in cardiac resynchronization therapy: clinical follow-up and predictors of failed lateral implant

The effects of the left ventricular (LV) pacing site on the clinical results of resynchronization therapy (CRT) are not well characterized. The aim of this study was to define the effect of LV lead location on clinical response and LV remodelling, and to identify predictors of failure to implant the LV lead in a lateral location. One hundred and seventy two consecutive patients were evaluated at baseline and 6 months after CRT. In 128 patients, the LV lead was implanted in the lateral region (Group 1), while 44 received an anterior implant due to anatomical or electrical factors (Group 2). Group 1 was associated with a significantly better functional outcome assessed both by NYHA class (p<0.001) and by the six-minute-walk test (p=0.01) compared with group 2. LV ejection fraction and volumes, and inter- and intraventricular dyssynchrony only improved significantly (p<0.01) in group 1. The only independent predictor of a failed lateral implant was the presence of ischaemic cardiomyopathy (OR 3.29, 95% CI 2.2-13.7; p=0.02). In conclusion, a lateral lead location results in a better functional outcome and greater reverse LV remodelling compared with anterior locations. The presence of ischaemic cardiomyopathy is a risk factor for a failed lateral LV implant.     

左心室扭转运动在心脏再同步治疗中的价值

<正>大量的循证医学证据表明,心脏再同步治疗(cardiac resynchronization therapy,CRT)能有效改善慢性心力衰竭患者的症状、提高生活质量、降低心力衰竭住院率和全因死亡率[1-2],已成为合并心脏不同步者的一线治疗手段。在CRT的发展过程中,超声心动检查发挥着不可或缺的作用。虽然在传统超声的基础上,组织多普勒、三维超声等新技术有了较大的发展,但目前仍缺乏有效的指标来预测CRT疗效。超声检测心脏扭转是近年来发展起来的新技术,因其独特的     

Left bundle branch–optimized cardiac resynchronization therapy (LOT-CRT): Results from an international LBBAP collaborative study group

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