心脏再同步化治疗与心力衰竭患者的心脏电学逆重构

目的探讨心脏再同步化治疗(CRT)是否会纠正心力衰竭患者的电重构现象。方法回顾分析伴有完全性左束支传导阻滞的心力衰竭患者接受CRT后随访观察1年,分别在术中电极安置后和术后1年测试自身心律下右室-左室电极的激动时间差(△t),右室电极刺激到左室电极感知时间(RVp-LV)及左室电极刺激到右室电极感知时间(LVp-RV),比较CRT应答者与无应答者的自身QRS波时限、双室起搏下QRS波时限和△t、RVp-LV、LVp-RV。结果共入选51例,应答组(36例),无应答组(15例)。应答组术前和术后1年相比,△t和RVp-LV缩短(P0.05)。无应答组术前与术后1年比较,△t、RVp-LV延长(P0.05)。两组自身QRS波时限无差异,但术后1年无应答组起搏下QRS波时限延长。结论 CRT应答患者发生了电学逆重构。起搏QRS波时限改变与CRT疗效有关。     

右心室起搏导线位置对心脏再同步治疗效果的影响

目的 评价右心室起搏导线位置对心脏再同步治疗（CRT）效果的影响.方法 71例顽固性心力衰竭患者接受CRT手术,53例左心室导线植入侧壁或侧后壁,18例植入前壁或下壁（非侧后壁）;48例右心室导线植入心尖部,23例植入流出道间隔部.术前记录受试者心功能（NYHA分级）、QRS时限（QRSd）、左心室射血分数（LVEF）、左心室舒张末期内径（LVEDD）及左心室收缩末期内径（LVESD）;术后6个月对上述参数进行随访,比较不同右心室起搏部位对CRT临床疗效的影响.结果 术后6个月,右心室心尖部起搏组LVEF高于流出道间隔部起搏组[（0.44±0.07）对（0.40±0.07）,P=0.048],余心功能、QRSd、LVEDD、LVESD等各项指标均差异无统计学意义（P＞0.05）.根据左心室起搏部位进一步分为侧壁或侧后壁与非侧后壁两组,就侧壁或侧后壁组,右心室心尖部起搏较间隔部起搏可更好地提高心输出量LVEF[（0.45±0.07）对（0.40±0.08）,P=0.027],改善心功能[（2.59±0.59）对（3.00±0.68）,P=0.038],对于非侧后壁组,比较右心室心尖部与流出道间隔部起搏,各项指标均差异无统计学意义（P＞0.05）.结论 若无视左心室起搏部位,右心室心尖部起搏略优于流出道间隔部起搏;而对于左心室侧壁和/或侧后壁起搏者,应尽量将右心室导线置于心尖部,以获得较好疗效.     

双心室起搏心电图的额面心电轴分析

目的 分析行心脏再同步治疗（CRT）的患者在不同起搏模式下的心电图QRS波电轴的分布特点,以及与左心室导线位置、左心室逆重构的关系.比较12导联同步心电图机自动分析与手动测量的心电轴的差异.方法 入选2012年11月到2013年6月在上海复旦大学附属中山医院行CRT植入的41例患者,分别记录患者术后3个月在单纯左心室起搏,左心室提前60ms、40ms、20ms、0ms,右心室提前20ms、40ms,单纯右心室起搏的12导联同步心电图共326份,记录12导联同步心电图机自动分析得出的心电轴,同时手动测量I和aVF导联QRS波的净振幅,代入公式：心电轴=57.3＆#215;ATAN（aVF/I）,计算相应的心电轴.比较术前、术后6个月超声心动图结果[左心室收缩未期内径（LVESD）],明确有无左心室逆重构发生.左心室逆重构定义为术后6个月LVESD减小≥15％.根据手术中左前斜位、后前位X线透视片明确左心室导线位置.结果 ①随着右心室起搏成分的减少,左心室成分的增加,QRS波额面电轴逐渐由左偏转为右偏（r,=0.412,P＜0.001）,不同的VV间期之间,QRS波额面电轴的分布不全相同（Pearson x2=68.7,P＜0.001）;②左心室导线植入部位与心电轴分布之间无明显的相关性（rs=0.08,P=0.149）;③在双心室同步起搏模式下,不同QRS波电轴分布范围,左心室逆重构的发生率差异无统计学意义（P=0.115）;④12导联同步心电图机自动分析与手动测量的QRS波额面电轴一致性程度一般（ICC=0.563,95％ CI：0.483～ 0.635,F=3.58,P＜0.001）.结论 VV间期的改变可使QRS波电轴产生迁移,起搏成分从右心室主导转移为左心室主导时,QRS波额面电轴出现顺时针偏移的现象.QRS波心电轴与左心室导线位置相关性差,仅根据心电轴难以判断左心室导线的位置.单一时间点双心室同步起搏QRS波电轴对于左心室逆重构无预测价值.12导联同步心电图机自动分析出的QRS波额面电?     

心电图与超声心动图优化VV间期的对比研究

目的 评价心电图在心脏再同步治疗（CRT）患者VV间期优化中的作用.方法 入选30例心功能Ⅲ～Ⅳ级（NYHA分级）CRT患者（男27例,女3例）,年龄42 ～79（63.3±10.6）岁.植入1个月后,分别程控为单独右心室起搏和单独左心室起搏,记录体表心电图.左心室起搏时,记录胸前导联从起搏信号到QRS波起始部假δ波结束之间的间期（T1）;右心室起搏时,记录胸前导联从起搏信号到QRS波开始改变之间的间期（T2）.T1 -T2的值为从心室侧壁与间隔部同步除极左心室所需的时间延迟,为最佳左-右心室激动的间期（Optimal VV间期）.同时采用超声扫描测定不同VV间期时的主动脉速度时间积分（VTI）,产生最大VTI间期为最佳VV间期,对比两种方法结果.结果 超声优化最佳VV间期在左心室领先起搏-30 ms、-70 ms时分别有20例、5例;左、右心室同步起搏（0 ～5 ms）时有3例;右心室领先起搏＋30 ms时有2例.心电图优化最佳VV间期在左心室领先起搏-30 ms、-70 ms时分别有19例和5例;左、右心室同步起搏时有4例;右心室领先起搏＋30 ms时有2例.两种方法相关性良好.结论 采用心电图可计算出CRT患者最佳VV间期,与超声心动图相关性良好.     

右心室高位室间隔起搏和心尖部起搏对心功能和左室重构的影响

目的:观察右心室高位室间隔起搏和心尖部起搏对心功能和左室重构的影响。方法:40例患者分别行右心室高位室间隔部起搏及右心室心尖部起搏治疗,于术前1d、术后6个月行常规心电图,超声心动图,24h动态心电图,血浆脑钠肽(BNP)检查。结果:与右心室心尖部起搏比较,右心室高位室间隔起搏QRS波时限增宽程度小,左心室射血分数(LVEF)及每搏出量(SV)降低程度小,左心室舒张末期内径(LVEDD)和BNP增加程度小。结论:右心室高位室间隔起搏与右心室心尖部起搏比较,对心室重构及心功能的不利影响较小,更接近生理性起搏,使血流动力学更接近生理状态,是更佳的起搏部位。     

心脏再同步化联合美托洛尔缓释片治疗老年扩张型心肌病心力衰竭的临床观察

目的观察心脏再同步化(cardiac resynchronization therapy,CRT)联合美托洛尔缓释片治疗老年扩张型心肌病顽固性心力衰竭的疗效。方法回顾性分析2010年6月至2012年3月绍兴第二医院,药物治疗效果不佳行右心房加CRT的老年扩张型心肌病顽固性心力衰竭患者21例的临床资料。18例患者植入右心房、右心室和冠状静脉左心室分支电极导线,行房室顺序CRT;3例心房颤动患者植入右心室和冠状静脉左心室分支电极导线。所有患者均服用美托洛尔缓释片,剂量(62.45±18.25)mg。术后4周、12周跟踪随访患者,观察心功能分级、6 min步行距离的变化、左心室舒张末期内径,左心室射血分数及二尖瓣反流。结果右心房、右心室和左心室导线感知和起搏参数均符合起搏要求,随访中亦未发现导线移位和功能障碍。起搏后QRS间期明显缩短,差异有统计学意义[(126±18)ms vs.(156±23)ms,P<0.05]。术后随访4周心功能分级提高到Ⅱ～Ⅲ级,左心室舒张末期内径为(62.5±17.6)mm,射血分数40%±13%,二尖瓣中度反流,6 min步行距离(486±189)m;12周时随访左心室舒张末期内径(56.5±12.4)mm,射血分数46%±17%,二尖瓣轻中度反流,6 min步行距离(565±139)m。结论CRT联合美托洛尔缓释片治疗可以缓解老年扩张型心肌病顽固性心力衰竭患者的症状,改善心功能,提高运动耐量,减轻二尖瓣反流。     

经心脏再同步治疗系统进行心脏收缩力调制的急性血流动力学研究

目的 研究经心脏再同步治疗(CRT)系统,不同范围的心脏收缩力调制(cardiac contractility modulation,CCM)对心力衰竭患者左心室收缩功能的影响.方法 连续入选2011年9月至2012年12月间19例接受心脏再同步治疗除颤器(CRT-D)植入术的患者,常规植入右心室及左心室导线,测试导线参数正常后连接导线至特制电生理刺激仪,并经桡动脉插入左心室压力导管至左心室,由心室起搏或感知体表心电图R波触发CCM刺激,确保CCM刺激发放于绝对不应期内.每个测试期间连续行CCM刺激30 s并同步记录左心室内压,术后分析左心室内压及左心室内压变化速率最大值(dp/dtmax).根据CCM刺激范围,将测试患者分为单独左心室、单独右心室或双心室间CCM组.结果 左心室CCM及右心室CCM(局部CCM)刺激未能明显改善左心室dp/dtmax,而双心室间进行CCM刺激提高左心室dp/dtmax达9.5％(P=0.007).结论 在双心室同步起搏基础上,双心室CCM刺激可以改善左心室收缩功能,可能使CRT患者额外获益,尤其适合对CRT无反应者.     

26例左心室主动固定导线应用的回顾性分析

目的评价左心室主动固定导线（Starfix^4195美国美敦力公司）在心脏再同步治疗（CRT）中的应用价值。方法分析自2010年7月至2012年8月在浙江大学医学院附属第二医院植入Starfix^4195导线的26例患者,男16例,女10例,平均年龄（68．1±7．7）岁,其中扩张型心肌病16例,缺血性心肌病5例,其他5例。观察Staffix^4195导线植入至最优起搏位点的手术成功率;术后中位随访10．5个月,观察出现左心室导线脱位、膈神经刺激及阈值升高等并发症的发生率。结果26例患者均成功植入Staffix^4195导线,手术成功率100％,24例患者（92．3％）左心室导线植入在最优起搏位点。CRT术后随访时间≥6个月的124例患者中,CRT有反应21例（87．5％）,无反应3例（12．5％）。术后中位随访10．5个月,左心室导线起搏阈值稳定,与术中比较无明显增高[（1．0±0．5）V对（1．2±0．7）V,P〉0．05],术后均未出现左心室导线脱位、膈神经刺激等并发症。结论在CRT植入术中,Starfix^4195导线能稳定固定在左心室最优起搏位点,明显提高手术成功率,并显著减少术后并发症。     

右心室间隔部起搏在心脏再同步化治疗中的应用观察

目的:探讨优化右心室起搏部位对心脏再同步化治疗疗效的影响。方法:5例扩张性心脏病患者,男性3例,女性2例,平均心力衰竭病史(4.1±09)年,平均左心室射血分数(LVEF)31.5%±11%,平均左心室舒张末直径(LVEDD):(63.2±16.5)mm,QRS宽度:(143±32)ms。所有患者均符合(CRT)植入Ⅰ类适应证。左心室起搏导线根据心脏静脉分布尽可能置于心源性休克(CS)左心室侧枝或后侧枝,右心室起搏导线置于右心室流出道间隔部。术后观察起搏QRS波图形,LVEF变化及随访观察患者纽约心脏病协会心脏分级(NYHA)心功能,生活质量及心脏重塑变化。结果:5例患者均成功植入CRT,其中     

左右心室导线间距与心脏再同步治疗中即刻疗效的关系

目的探讨右心室起搏部位改变时,左、右心室导线间距对心脏再同步治疗（CRT）即刻疗效的影响。方法对25例符合适应证患者行CRT手术,术中将左心室导线植入侧壁或侧后壁,先后将右心室导线植入右心室流出道和右心室心尖部,分别测得主动脉速度血流积分及心肌收缩达峰时间标准差,同时比较此2种不同部位左、右心室导线间距,包括直接、垂直和水平距离（分别由正位及左侧位投影时测得）的差异。结果右心室心尖部起搏主动脉速度血流积分显著高于右心室流出道起搏[（15．76±2．29）cm对（14．71±2．12）cm,P〈0．001],QRS时限则显著较窄[（141．84±20．89）ms对（159．84±19．56）ms,P〈0．001]。右心室心尖部起搏侧位投影下的导线间距（校正后）显著大于右心室流出道起搏[（161．23±44．58）mm对（121．34±55．91）mm,P〈0．001],其垂直距离（校正后）亦显著大于后者[（97．65±45．73）mm对（39．41±23．51）mm,P〈0．001]。结论CRT术中改变右心室起搏部位时,侧位投影下的左、右心室导线间距较大者CRT手术即刻反应较佳。     

右室感知触发左室起搏心脏再同步化治疗慢性充血性心力衰竭

目的探讨右室感知触发左室起搏心脏再同步化治疗(CRT)慢性充血性心力衰竭(CHF)的效果。方法植入三腔起搏器进行心脏超声优化的CHF患者30例,分别测定传统CRT优化后及右室感知触发左室起搏CRT模式的左室射血分数(LVEF)、舒张期二尖瓣血流速度时间积分(MVI)、二尖瓣返流VTI(MR-VTI)、主动脉瓣前向血流VTI(AVI),并与CRT术前及传统CRT右室优先模式(11例)比较上述心脏超声指标、QRS波时限、优化耗时及CRT费用的差别。结果右室感知触发左室起搏模式的平均电池寿命长于传统CRT模式,QRS波时限、优化耗时及CRT年平均费用少于传统CRT模式(均P<0.01);AVI、LVEF、MVI、MR-VTI与传统CRT模式无差异(均P>0.05),但与传统CRT模式高度相关(P<0.01)。右室感知触发左室起搏模式的AVI、LVEF、MVI较右室优先模式增加,MR-VTI较右室优先模式减少(P均<0.05)。结论右室感知触发左室起搏较右室优先的传统CRT模式改善CHF患者的血流动力学,降低CRT年平均费用。     

Tricuspid Annular Plane Systolic Excursion Evaluation Improves Selection of Cardiac Resynchronization Therapy Patients

Background

The beneficial effects of cardiac resynchronization therapy (CRT) on left ventricular (LV) remodeling have been extensively described. Few data are available about the effects of CRT on right ventricular (RV) function and remodeling.

Hypothesis

We hypothesized that CRT could also induce reverse remodeling in the right ventricle and that RV baseline functional status expressed as tricuspidal annular plane systolic excursion (TAPSE) could affect CRT response.

Methods

Echocardiographic investigation was performed before and 6 months after CRT. In 192 patients, TAPSE, LV, and RV dimensions with functional parameters and LV dyssynchrony index were evaluated.

Results

At 6 months' follow‐up, 86 patients (45%) were responders to CRT according to at least 15% LV end‐systolic volume reduction. Among baseline echocardiographic parameters, responders had significantly lower TAPSE, larger LV volumes, and higher LV dyssynchrony index. In responders, LV volume reduction, ejection fraction increase, and mitral regurgitation improvement were associated with RV dimensions reduction, increased TAPSE, and improved LV dyssynchrony. Receiver operating characteristic curve analysis showed that TAPSE, at 17 mm optimal cutoff, yielded 64% sensitivity and 60% specificity in predicting CRT response; similarly, LV dyssynchrony index, at 41.25 ms optimal cutoff, predicted CRT response with 60% sensitivity and 62% specificity. A subgroup analysis demonstrated that the coexistence of high TAPSE and high dyssynchrony index values increased probability of CRT response.

Conclusions

Our results show that CRT induces RV and LV reverse remodeling and that CRT patient selection can be improved by simply measuring TAPSE value. Copyright © 2010 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.     

Contractile Reserve Assessed Using Dobutamine Echocardiography Predicts Left Ventricular Reverse Remodeling after Cardiac Resynchronization Therapy: Prospective Validation in Patients with Left Ventricular Dyssynchrony

Background: The presence of viable myocardium may predict response to cardiac resynchronization therapy (CRT). The aim of this study is to evaluate in patients with left ventricular (LV) dyssynchrony whether response to CRT is related to myocardial viability in the region of the pacing lead. Methods: Forty‐nine consecutive patients with advanced heart failure, LV ejection fraction < 35%, QRS duration > 120 ms and intraventricular asynchronism ≥ 50 ms were included. Dobutamine stress echocardiography was performed within the week before CRT implantation. Resting echocardiography was performed 6 months after CRT implantation. Viability in the region of LV pacing lead was defined as the presence of viability in two contiguous segments. Response to CRT was defined by evidence of reverse LV remodeling (≥15% reduction in LV end‐systolic volume). Results: Thirty‐one patients (63%) were identified as responders at follow‐up. The average of viable segments was 5.9 ± 2 in responders and 3.2 ± 3 in nonresponders (P = 0.0003). Viability in the region of the pacing lead had a sensitivity of 94%, a specificity of 67%, a positive predictive value of 83%, and a negative predictive value of 86% for the prediction of response to CRT. Conclusions: In patients with LV dyssynchrony, reverse remodeling after CRT requires viability in the region of the pacing lead. This simple method using echocardiography dobutamine for the evaluation of local viability (i.e., viability in two contiguous segments) may be useful to the clinician in choosing the best LV lead positioning. (Echocardiography 2010;27:668‐676)     

Effects of interruption of long-term cardiac resynchronization therapy on left ventricular function and dyssynchrony

Interruption of short-term cardiac resynchronization therapy (CRT) has been shown to acutely worsen left ventricular (LV) function, mitral regurgitation, and LV dyssynchrony. The present study aims to assess whether LV reverse remodeling influences interruption of CRT, and, more practically, whether long-term continuous pacing is necessary in patients with reverse LV remodeling. A total of 135 recipients of CRT were selected after showing LV reverse remodeling defined as a decrease in LV end-systolic volume >/=15% after 6 months of CRT ("responders"). Echocardiography was performed at baseline and after 6 months with intermittent CRT on and off. LV dyssynchrony was determined using tissue Doppler imaging. During interruption of CRT, an acute deterioration in LV function, mitral regurgitation, and LV desynchronization were noted in responder patients. Of note, worsening of these echocardiographic measurements was observed, but they did not return to baseline values. For comparison, 100 nonresponder patients (without LV reverse remodeling) showed no significant echocardiographic changes during interruption. In conclusion, despite the presence of LV reverse remodeling, interruption of CRT resulted in worsening of LV function and desynchronization. Therefore, continuous long-term pacing is warranted to maintain the beneficial effects.     

The influence of myocardial scar and dyssynchrony on reverse remodeling in cardiac resynchronization therapy.

AIM: The influence of location and extent of transmural scar and its relation with dyssynchrony in cardiac resynchronization therapy (CRT) was investigated as posterolateral scar tissue has been invoked as a cause of non-response to CRT. METHODS AND RESULTS: Fifty-seven patients eligible for CRT were assessed for transmural scar with gadolinium-enhanced MRI and for left ventricular (LV) dyssynchrony with tissue Doppler. After implant, both atrioventricular and interventricular pacing intervals were optimized. LV reverse remodeling was defined as >/=10% decrease in LV end-systolic volume after 3 months. Sixteen patients had transmural scar in the posterolateral (PL) area (LV lead location), 14 at a remote site (non-PL) and 27 patients had no scar. LV reverse remodeling was observed in respectively 25%, 64% and 89% (P = 0.0001). Univariate analyses showed a relation with LV dyssynchrony (P = 0.004) and with absence of PL scar (P = 0.04) but not with QRS duration and the extent of LV scar tissue. In multivariate analysis, only LV dyssynchrony (OR: 19.62; 95% CI: 2.5-151.9; P = 0.004) independently predicted LV reverse remodeling. CONCLUSION: In this study LV dyssynchrony remains the most important determinant of response to CRT, even in the presence of posterolateral scar provided atrioventricular and interventricular pacing intervals are optimized.     

Clinical and procedural characteristics of acute hemodynamic responders undergoing triple-site ventricular pacing for advanced heart failure

The advantages of triple-site ventricular pacing (Tri-V) compared to conventional biventricular site pacing (Bi-V) have been reported. We sought to identify the predictors of acute hemodynamic Tri-V responders. Acute hemodynamic studies were performed in 32 patients with advanced heart failure during Tri-V implantation. After the right ventricular (RV) and left ventricular (LV) leads were implanted for a conventional Bi-V system, an additional pacing lead was implanted in the RV outflow tract for Tri-V. The LV peak +dP/dt and tau were measured during AAI, Bi-V, and Tri-V pacing. A Tri-V responder was defined as a patient whose percentage of increase in the peak +dP/dt during Tri-V was >10% compared to of that during Bi-V. The baseline clinical variables and RV outflow tract lead location were analyzed to identify the characteristics of the Tri-V responders. Of the 32 patients, 10 (31%) were classified as Tri-V responders. The LV end-diastolic volume was greater (246 ± 48 vs 173 ± 53 ml, p <0.01), and the RV outflow tract lead was implanted at a greater outflow tract portion (p <0.05) in the Tri-V responders. Multivariate analysis revealed that only the baseline LV end-diastolic volume (per 50-ml greater) predicted the Tri-V response (odds ratio 2.87, 95% confidence interval 1.03 to 8.00, p <0.05). The area under the receiver operating characteristic curve for the LV end-diastolic volume was 0.84 (p <0.01) and an LV end-diastolic volume of >212 ml had a sensitivity of 80% and specificity of 77% to distinguish Tri-V responders. In conclusion, Tri-V provides greater hemodynamic effect for patients with a larger LV end-diastolic volume owing to its resynchronization effects on the LV anterior wall.     

左心室不同部位起搏对心脏再同步治疗效果的影响

目的 探讨左心室不同部位起搏对心脏再同步治疗（CRT）效果的影响.方法 2008年1月至2011年12月在中南大学湘雅二医院成功植入CRT起搏器/除颤器（CRT-P/D）患者41例.根据逆行心脏静脉多体位造影确定左心室导线起搏部位,按照右前斜位30°心脏长轴造影分为基底部组（n=15）、室中部组（n=26）和心尖部组（n=0）;按照左前斜位45°心脏短轴造影分为前壁组（n=9）、前侧壁组（n=10）、侧壁组（n=12）、后侧壁组（n=10）和后壁组（n=0）.随访记录并比较各组基线（术前）,术后7d,3、6、12、18、24个月时左心室射血分数（LVEF）、左心室舒张末期内径（LVEDD）、QRS时限、心功能（NYHA分级）、6 min步行试验、明尼苏达（Minnesota）心力衰竭生活质量评分、CRT参数变化及并发症情况.结果 ①41例患者无应答率为19.5％（8/41）;术后各随访时间点与基线时相比,所有患者LVEF升高、LVEDD下降、QRS时限缩短、心功能改善、6 min步行试验距离增大、明尼苏达心力衰竭生活质量评分下降（P＜0.05）;②随访3个月后各时间点,非前壁（前侧壁、侧壁或后侧壁）组在LVEF、心功能、6 min步行试验及明尼苏达心力衰竭生活质量评分等指标改善均优于前壁组（P＜0.05）;LVEDD下降各组间相比差异无统计学意义（P＞0.05）;前侧壁、侧壁和后侧壁组间相比,上述指标差异无统计学意义（P＞0.05）;③各随访时间点,基底部与室中部组间相比,LVEF、LVEDD、QRS时限、心功能、6 min步行试验及明尼苏达心力衰竭生活质量评分等指标改善差异无统计学意义（P＞0.05）;④所有患者术后随访CRT参数变化差异无统计学意义（P＞0.05）,工作正常,无心力衰竭再入院、导线脱位、膈肌起搏、囊袋感染等不良事件.结论 ①CRT可使慢性心力衰竭患者长期获益;②左心室导线起搏部位前壁者CRT疗效可能较前侧壁、侧壁或后侧壁者?     

Tissue synchronization imaging and optimal left ventricular pacing site in cardiac resynchronization therapy

The optimal pacing site in cardiac resynchronization therapy (CRT) remains controversial. Tissue synchronization imaging is a novel echocardiographic technique that color-codes for areas of maximal delay in myocardial velocities. This study aimed to identify whether the left ventricular (LV) pacing lead position in CRT should be guided by a patient's area of maximal mechanical delay. Fifty-four patients with advanced heart failure were assessed echocardiographically before and 6 months after CRT. Response was analyzed according to the relation between the LV lead position and the area of maximal delay to peak velocity by tissue synchronization imaging in the first half of the ejection phase: group 1 (n = 22) had lead placement corresponding to the segment of maximal delay; group 2 (n = 13) had lead placement 1 segment adjacent; and group 3 (n = 19) had lead placement remote from this site. Evidence of LV reverse remodeling and improved systolic function was documented in group 1 (mean percentage decrease in end-systolic volume 23%) more than in group 2 (mean decrease 15%), and more than in group 3 (mean increase 8.9%, p <0.0001 compared with groups 1 and 2). In group 1, 16 of 22 patients had reverse remodeling (>15% decrease in end-systolic volume); reverse remodeling was seen in 7 of 13 patients in group 2 and 1 of 19 in group 3. The placing of the lead position proximal to the site of maximal delay by tissue synchronization imaging was correlated with reverse remodeling (r = 0.449, p = 001). Of 7 patients with delay confined to the septum and anterior wall only, none had evidence of reverse remodeling after CRT. In conclusion, pacing at the site of maximal mechanical delay was associated with reverse remodeling. Individually tailored LV lead positioning should be considered before CRT.