心室不同部位起搏引发无人区心电轴的研究

目的观察心室不同部位起搏时体表心电图QRS波额面无人区电轴的发生情况,探讨无人区电轴在不同部位的室性异位激动中的意义。方法将左右心室分为12个区域。43例患者快速心律失常射频消融术成功后,应用消融导管在左、右心室的不同分区行高于自主心率的固率起搏并同步记录体表12导联起搏心电图,测量Ⅰ、Ⅲ标准导联QRS波振幅的代数和并计算QRS波平均心电轴。结果左、右心室共起搏279例次,其中35例次起搏心电图发生额面电轴位于无人区,均起源于左室。28例次心电轴位于-90°～-150°之间,7例次心电轴位于-150°～-180°之间。右室不同分区的起搏心电图均未出现无人区电轴,左室分区中除前壁基底部以外的起搏部位都可能出现无人区电轴。结论起源于左室多个区域的异位激动的额面电轴都可位于无人区,起源于右室的异位激动未出现无人区电轴。     

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.     

特发性室性心动过速射频导管消融标测方法探讨

目的探讨特发性室性心动过速（IVT）的标测方法.方法对52例行射频消融的IVT患者进行标测.39例源于右心室的IVT采用消融导管右心室起搏标测法,以起搏时与室性心动过速（室速）发作时的12导联心电图QRS波形态与振幅完全相同的起搏部位为消融靶点.12例起源于左心室的IVT以发作时消融电极导管在左心室内标测到较体表心电图QRS波提前≥20 ms的最早高频低振幅电位为消融靶点（激动顺序标测法）,1例左心室室速采用起搏标测法.结果左心室IVT消融成功率100%（13/13）,右心室IVT消融成功率94.87%（37/39）.结论起源于左心室的IVT宜采用激动顺序标测法,起源于右心室的IVT宜采用起搏标测法.     

右心室不同位点起搏对QRS时限的影响

目的 观察右心室不同起搏位点的QRS时限,为临床导线放置提供参考依据.方法 选择216例符合Ⅰ类或Ⅱa类起搏器植入适应证的患者,在放置心室导线过程中,分别在右心室心尖部、流入道、中位间隔部、高位间隔部和流出道等不同位点起搏右心室,记录起搏时的体表心电图,比较不同位点QRS时限和形态的差异.结果 与基础心电图QRS波比较,所有右心室起搏部位心电图QRS时限均明显增宽(P＜0.001)；以心尖部起搏QRS时限增宽(168±16) ms,其次为流入道(166±15) ms和流出道(165±15) ms；三者比较差异无统计学意义(P＞0.05).间隔部起搏QRS时限明显缩短(P＜0.001),且QRS波形态和电轴正常.中间隔部最短(139± 19) ms,高位间隔部次之(153±14) ms,二者相比差异有统计学意义(P＜0.01).结论 在所有右心室起搏位点中,中间隔部起搏QRS时限最窄,且形态和电轴正常.中间隔部可能是右心室最理想起搏选择位点.     

三维超声评价起搏心电图对右心室流出道起搏电极导线的定位作用

目的 根据三维超声心动图精确定位的起搏心电图特点来评价起搏电极导线位于右心室流出道的位置.方法 40例植入永久性起搏器的患者,植入术中经二维X线影像定位示心室起搏电极导线位于右心室流出道高位间隔部,植入术后行心脏三维超声心动图检查以评价心室电极导线位于右心室流出道的精确位置,并分析起搏电极导线位于不同部位的体表起搏心电图特点.结果 三维超声心动图示起搏电极导线位于高位间隔者23例(57.5%),低位间隔者6例(15.0%),游离壁者11例(27.5%).与游离壁相比,起搏电极导线位于高位间隔时,其下壁导联起搏心电图的R波振幅高[(1.28±0.18)mV vs(0.88±0.18)mV,P＜0.001]、QRS时限短[(132.5±8.3)ms vs(155.3±6.9)ms,P＜0.001]、顿挫少(21.7% vs 90.9%,P＜0.001),胸前导联R/S移行早(大于V4,24%vs 81%,P＜0.05);起搏电极导线位于低位间隔时,其R波振幅也较高[(1.43±0.13)mV vs(0.88±0.18)mV,P＜0.001]、时限也较短[(143.5±4.3)ms vs(155.3±6.9)ms,P=0.004],胸前导联R/S移行早(大于V4,24%vs 81%,P＜0.05).而高位间隔与低位间隔相比,高位间隔QRS波时限更短[(132.5±8.3)ms vs(143.5±4.3)瑚,P=0.003].另外,当起搏电极导线位于后间隔时,Ⅰ导联上的QRS波以正向波为主,位于前间隔时则以负向波为主.结论 三维超声心动图有利于心室起搏电极导线在右心室流出道的精确定位;不同部位起搏的心电图具有不同的特点,这些特点有利于植入术中起搏电极导线在右心室流出道的定位,当起搏电极导线位于后间隔时,其起搏心电图Ⅰ导联为正向波,前间隔时为负向波.     

心脏再同步治疗术中测试腔内心电图参数的临床意义

目的 探讨心脏再同步治疗（CRT）术中测定腔内心电图参数,尤其是左心室激动延迟时间是否可以预测心力衰竭患者左心室逆重构发生.方法 2009年1月至2013年1月37例完全性左束支阻滞患者在天津市胸科医院心内科植入CRT,术中测试窦性心律自身传导情况下右心室-左心室导线的激动时间差（△t）,测试右心室导线起搏到左心室导线感知时间（RVp-LV）及左心室导线起搏到右心室导线感知时间（LVp-RV）.随访观察1年,比较术前、术后心脏结构变化,以左心室舒张末期容积减小15％或射血分数提高5％为标准分为CRT应答组和无应答组.结果 左心室逆重构的发生与术中测试腔内心电图△t、RVp-LV、LVp-RV等参数均无明显关系,△t与术前QRS时限有关,RVp-LV、LVp-RV在左心室舒张末期内径（LVEDD） ＞75 mm的患者中长于LVEDD≤75 mm的患者（P＜0.05）.左心室导线植入在左心室基底部、中段、心尖部的患者发生左心室逆重构的比例分别为71.4％、90.4％、12.5％,差异有统计学意义（P＜0.05）,3个部位的△t、RVp-LV、LVp-RV差异无统计学意义.结论 术中测定腔内心电图相关参数不能预测CRT是否应答,左心室导线位置仍是决定CRT疗效的关键因素.     

正常人额面QRS电轴的年龄趋势以及对肢体导联QRS波振幅的影响

目的调查和评估正常人额面QRS电轴的年龄趋势以及对肢体导联QRS波振幅的影响。方法采集5360例(男性3614例、女性1746例,年龄范围18～84岁)正常健康人12导联心电图分为5个年龄组,计算和分析各年龄组额面QRS电轴的中位数以及肢体导联QRS波振幅的中位数和96%的正常范围上、下限。结果随年龄增长,男、女额面QRS中位数电轴一致性地逐渐向左(上)偏移大约27°(从70°偏移到43°,P＜0．001)。Ⅰ和aVL导联的R波振幅随年龄增长显著增加(P＜0．001),而下壁导联Ⅱ、Ⅲ和aVF的R波振幅随年龄增长显著降低(P＞0．001)。肢体导联R波振幅随年龄的变化趋势与额面QRS电轴的年龄趋势相一致。结论正常人额面QRS电轴随年龄增长逐渐向左(上)偏移,呈现明确的年龄趋势。QRS电轴的生理性演变可引起肢体导联QRS波振幅呈现明显的年龄差异。显然,把一个相同的左心室肥大心电图诊断标准应用到不同年龄组人群是不合适的。     

右心室间隔部与心尖部起搏对心功能影响的对比研究

目的探讨右心室心尖部起搏与右心室间隔部起搏对心室电极植入手术的效果。方法选取完全性房室传导阻滞、窦性心动过缓、有症状的慢-快综合征需置入起搏器的患者90例,随机分为两组,A组45例,采用主动固定电极行右心室间隔部起搏;B组45例,采用被动固定电极行右心室心尖部起搏。观察两组手术时间,术后12个月复查超声心动图,对比治疗前后左心室射血分数（LVEF）、左心室舒张末内径（LVEDD）、室间隔厚度（IVS）、左心室后壁厚度（LVPW）及心电图胸前导联QRS波宽度。对比两组起搏参数和心电图QRS间期相关资料。结果 A组手术平均时间（50.51±6.52）min,B组手术平均时间（63.52±7.34）min,B组手术时间略长,差异有统计学意义（P〈0.05）。两组治疗后LVEF、LVEDD、IVS、LVPW与治疗前比较无统计学意义,且两组比较差异也无统计学意义（P〉0.05）。两组术中RVS起搏阈值、感知阈值、电极阻抗比较差异无统计学意义（P〉0.05）。术后A组心脏指数（CI）、每搏量（SV）、二尖瓣血流E峰和A峰最大充盈速度比值（E/A）明显高于B组,A组起搏的QRS波宽度窄于B组,差异均有统计学意义（P〈0.05）。与B组起搏相比,RVS起搏时心电轴、QRS波群与正常心室激动顺序的QRS波群形态相似。结论右心室间隔部起搏同期左心室功能、同步性与血流动力优于右心室心尖部起搏者,右心室室间隔起搏更有利于保持患者心功能的稳定。     

VVI起搏反复搏动伴双向性双径路传导1例

患者女性,68岁.临床诊断:冠心病,病态窦房结综合征.植入VVI起搏器5年.体表心电图(图1)示:起搏频率71次/min.起搏信号规律出现,其后均随有QRS波群,起搏QRS波群呈完全性左束支传导阻滞型加额面QRS电轴左偏,符合右心室起搏图形.窦性P波不规则出现,间歇呈现起搏QRS-P~(-)-室上性QRS波群序列.根据R-P~(-)和P~(-)-R间期长短的变化分为4组:(1)R-P~(-)间期520ms,P~(-)-R间期320ms为逆向和顺向均沿慢径路传导(图1上行R_1-R_2、R_6-R_7、下行R_-R_2);(2)R-P~-间期520ms,P~--R间期220ms,是逆向经慢径路而顺向经快径路传     

三腔双心室起搏治疗20例充血性心力衰竭患者的近期临床效果

目的 观察三腔双心室同步起搏治疗充血性心力衰竭的临床效果。方法 充血性心力衰竭伴心室内阻滞患者20例,男性16例,女性4例,平均年龄54.7岁。心功能均在Ⅲ-Ⅳ（NYHA分级）,体表心电图平均QRS时限为142.6ms。患者均进行了三腔双心室同步起搏,起搏电极导线分别置于右心房、右心室以及经由冠状静脉窦置于一支心脏静脉起搏左心室。观察双心室起搏前后左心室射血分数变化以及体表心电图QRS波变化。结果 双心室同步起搏后,患者心功能得到明显改善,左心室射血分数（left ventricular ejection fraction,LVETF)从24.4%提高至32.1%,左心室充盈时间延长,二尖瓣返流量减少,心功能从Ⅲ-Ⅳ级改善至Ⅱ-Ⅲ级,QRS时限由术前的142.6ms缩短至124.8ms。结论 初步临床观察提示,三腔双心室同步起搏可有效改善充血性心力衰竭伴心室内阻滞患者的心功能。     

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。     

心脏再同步治疗对心肌复极离散度的影响

目的观察心室不同位点起搏时心电图上心肌复极标志的变化,了解以双心室起搏技术为核心的心脏再同步治疗（CRT）对心肌复极离散的影响。方法 入选接受CRT植入的患者在起搏器植入后1周内记录12导联心电图,分别将起搏器程控为无起搏、右心室内膜下起搏（RV—EndoP）、左心室外膜起搏（LV—EpiP）及双心室同步起搏（BivP）四种不同状态并记录心电图。阅读不同起搏位点时的QRS时限、QT问期及TP-E时限。QTc用Bazett公式[QTc=实测QT／（RR）1／2]进行矫正。结果基线QYc为（489．2±51．2）ms,而RV—EndoP、LV—EpiP起搏导致QR明显延长[RV-EndoP（537．3±45．7）ms,P〈0．05;LV—EpiP（592．4±60．2）ms,P〈0．001],而BivP起搏为（491．3±52．7）ms,P〉0．05;基线TP．F（113．8±15．7）ms,RV-EndoP、LV—EpiP均导致TP-E明显延长[RV．EndoP（124．8±24．7）ms,P〈0．05;LV．EpiP（133．3±37．8）ms,P〈0．005],BivP时TP-E时限为（109．9±17．1）ms,有轻度缩短,但差异没有统计学意义（P〉0．05）。结论左心室外膜起搏可明显延长心肌复极离散指标;双心室同步起搏可减少由单纯左心室外膜起搏引起的复极离散度的增大。     

右室心尖部起搏患者起搏QRS波时限与左室结构和功能关系探讨

目的评价起搏QRS波时限与左心结构和功能的关系。方法入选106例右室心尖起搏患者,分成左室射血分数(LVEF)<0.55的病例组(n=48)和LVEF>0.55的对照组(n=58)。通过常规体表心电图测得起搏QRS波时限,行超声心动图检查获取左房内径(LAD)、收缩末期左室内径(LVESD)、舒张末期左室内径(LVEDD)、室间隔厚度(IVST)、左室后壁厚度(LVPWT)及LVEF,评价患者的纽约心功能分级,同时检测患者的N端-B型利钠肽前体(NT-proBNP)水平,分析起搏QRS波时限与以上各指标的关系。结果①起搏QRS波时限与LVEDD(r=0.577,P<0.001)、LVESD(r=0.627,P<0.001)、LAD(r=0.241,P=0.013)、IVST(r=0.345,P<0.001)、LVP-WT(r=0.349,P<0.001)均呈正相关,与LVEF负相关(r=-0.570,P<0.001),与纽约心功能分级正相关(r=0.527,P<0.001),与NT-proBNP对数正相关(r=0.265,P=0.024)。②以起搏QRS波时限≥200ms诊断左室收缩功能不全,灵敏度和特异度分别为85.42%和70.69%。结论对于右室心尖部起搏的患者,起搏QRS波时限是一个简便而实用的初步判断心脏结构和功能的指标。     

Interventricular delay interval optimization in cardiac resynchronization therapy guided by echocardiography versus guided by electrocardiographic QRS interval width

Present devices for cardiac resynchronization therapy offer the possibility of tailoring the hemodynamic effect of biventricular pacing by optimization of the interventricular delay (VV) beyond atrioventricular (AV)-interval optimization. It was not yet defined whether a QRS width-based strategy may be a helpful tool for echocardiography for device programming. The aim of the study was to investigate the relation between VV-interval optimization guided by echocardiography and guided by QRS interval width. One hundred six patients with a cardiac resynchronization therapy device for > or =3 months were enrolled. All patients underwent echocardiographic AV and VV delay optimization. The AV interval was optimized according to the E wave-A wave (EA) interval and left ventricular filling time. At the optimal AV delay, VV optimization was performed by measuring the aortic velocity time integral at 5 different settings: simultaneous right and left ventricle output, left ventricle pre-excitation (left ventricle + 40 and 80 ms, respectively), and right ventricle pre-excitation (right ventricle + 40 and 80 ms, respectively). A 12-lead electrocardiogram was recorded and QRS duration was measured in the lead with the greatest QRS width. The electrocardiographic (ECG)-optimized VV interval was defined according to the narrowest achievable QRS interval among 5 VV intervals. The echocardiographic-optimized VV interval was left ventricle + 40 ms in 28 patients, left ventricle + 80 ms in 15 patients, simultaneous in 46 patients, right ventricle + 40 ms in 14 patients, and right ventricle + 80 ms in 3 patients. Significant concordance (kappa = 0.69, p <0.001) was found between the echocardiographic- and ECG-optimized VV interval. In conclusion, significant concordance appeared to exist during biventricular pacing between VV programming based on the shortest QRS interval at 12-lead ECG pacing and echocardiographic-guided VV-interval optimization. A combined ECG- and echocardiographic approach could be a less time-consuming solution in performing this operation.     

左心室心外膜不同部位起搏对心室不应期离散度的影响

目的:通过模拟心脏再同步治疗中左室电极在左心室心外膜不同部位起搏情况,观察不同部位起搏对心室不应期离散度的影响。方法:采用6只犬开胸,在其左心室前侧壁心外膜缝上1块含有144(12×12)个单极电极(电极间距2 mm)的电极板。选取位于电极板对角处的2个起搏部位(左上角靠近心底部,右下角靠近心尖部),采用连续起搏方法,记录起搏周期为300 ms时整个电极板上每个单极电极上的激动恢复间期,通过其标准差及变异系数评估不应期离散度。结果:近心底部与近心尖部起搏时起搏阈值及心室激动恢复间期无显著差异[起搏阈值(0.34±0.22)mA比(0.26±0.05)mA;激动恢复间期(144.3±12.4)ms比(147.7±14.8)ms,均P>0.05]。但是,近心底部位起博的不应期离散度较近心尖部起搏的不应期离散度显著减小[标准差(4.3±0.8)ms比(5.8±0.7)ms,P<0.01;变异系数(0.030±0.006)比(0.039±0.005),P<0.01]。结论:在心脏再同步治疗左室电极植入过程中,选择恰当的左室电极植入部位有利于降低不应期离散度。     

右心室流出道与右心室心尖部起搏对心室收缩同步性和心功能的影响

目的研究右心室流出道(right ventricular outflow tract,RVOT)间隔部和右心室心尖部(right ventricularapex,RVA)起搏对心脏收缩同步性、收缩功能的影响,探讨RVOT间隔部起搏的意义。方法 50例病态窦房结综合征患者分为RVOT组(n=25)和RVA组(n=25),起搏器置入1个月后通过调整房室间期使心室节律全部为起搏节律或房室结自身下传节律,观察起搏参数,并行超声心动图检查。结果RVOT组与RVA组电极导线植入时间、X线曝光时间比较,差异无统计学意义(P>0.05)。全部患者未出现植入并发症。两组随访1个月时起搏参数比较,差异无统计学意义(P>0.05)。RVOT组和RVA组起搏后的QRS波时限较前明显增宽,差异有统计学意义[RVOT组:(135±8)ms vs.(88±8)ms,P<0.001;RVA组:(154±8)ms vs.(90±6)ms,P<0.001]。RVA组起搏后QRS波时限较RVOT组增宽更为明显,差异有统计学意义(P<0.001)。两组起搏后室间机械延迟(interventricularmechanical delay,IVMD)和室间隔-左心室后壁收缩运动延迟时间(septal-to-posteriowall motion delay,SPWMD)较起搏前均显著增加,差异有统计学意义(P<0.001)。RVA组起搏后IVMD和SPWMD绝对值较RVOT组显著延长,差异有统计学意义[IVMD:(38±7)ms vs.(24±5)ms,P<0.001;SPWMD:(118±21)ms vs.(60±11)ms,P<0.001]。两组左心室舒张末内径及左心室射血分数比较,差异无统计学意义(P>0.05)。结论右心室起搏会造成心室收缩不同步,RVOT起搏对心室收缩不同步的影响较RVA起搏小,提示RVOT起搏是较为生理的起搏位点。     

Calculation of effective VV interval facilitates optimization of AV delay and VV interval in cardiac resynchronization therapy

BACKGROUND: In hearts with left bundle branch block (LBBB), both atrioventricular (AV) delay and interventricular (VV) interval determine left ventricular (LV) pump function in cardiac resynchronization therapy (CRT). The optimal combination of AV delay and VV interval currently is determined by extensive hemodynamic testing. OBJECTIVES: The purpose of this study was to investigate whether the effective VV interval (VV(eff)) can be used to optimize AV delay and VV interval. METHODS: In eight canine hearts with chronic LBBB, LV pacing was performed at various AV delays as well as biventricular pacing at multiple AV delays and VV intervals. LV pump function was assessed from LVdP/dt(max) and stroke volume (conductance catheter). Interventricular asynchrony was calculated from the timing difference between upslope of LV and RV pressure curves. VV(eff) was defined as the time delay between activation of the RV apex and LV lateral wall, irrespective of the source of RV activation (RV pacing or intrinsic conduction). VV(eff) was determined from pacemaker settings and surface ECGs recorded during biventricular pacing at various AV delays (positive values denote LV preexcitation). RESULTS: For all animals, the relationship between VV(eff) and LVdP/dt(max) as well as LV stroke work was parabolic. Maximal improvement in LVdP/dt(max) was similar during LV pacing, simultaneous biventricular pacing, and sequential biventricular pacing and was obtained at similar values of VV(eff). VV(eff) was strongly correlated with interventricular asynchrony (R = 0.97 +/- 0.03). Optimum LVdP/dt(max) occurred at VV(eff) ranging from -24 to 12 ms (mean -6 +/- 13 ms). For each experiment, the optimal VV(eff) was virtually equal to the value halfway between its minimum (during LV pacing at short AV delay) and maximum (during LBBB) value (R = 0.91). CONCLUSION: Use of VV(eff) facilitates determination of the best combination of AV delay and VV interval during biventricular pacing. For each individual heart, VV(eff), resulting in optimum LV pump function, can be estimated using surface ECGs recorded during biventricular pacing.     

心脏再同步治疗的随访及疗效观察

目的探讨心脏再同步化起搏治疗（CRT）的长期疗效以及随访相关技术细节。方法15例慢性心力衰竭患者,男性13例,女性2例,平均年龄72．25岁,其中扩张性心肌病8例、缺血性心肌病5例、高血压性心脏病2例。按常规方法置入CRT后对起搏系统参数进行优化,观察长期疗效。结果随访12个月,经过双心室起搏辅以优化的起搏参数及药物治疗,左心室射血分数从29％提高至42％,差异有统计学意义（P〈0．01）;左心室舒张末内径从65．8mm缩小至59．6mm,差异有统计学意义（P〈0．01）;QRS波从144ms缩短至124ms,差异有统计学意义（P〈O．01）;心衰临床症状减轻,心功能改善,运动耐量增加,生活质量提高,心脏重塑进程延缓,因而心衰住院事件减少。结论CRT能够使心衰患者临床症状减轻,心功能改善,生活质量提高,心脏重塑进程延缓。随访优化起搏参数和药物治疗对提高疗效是十分重要的。     

Evidence of reverse remodeling after long-term biventricular stimulation for resynchronization in patients with wide QRS selected on the basis of echocardiographic electromechanical delays.

BACKGROUND: There is increasing evidence that cardiac resynchronization therapy (CRT) may trigger an inverse remodeling process leading to decreased left ventricular (LV) volumes in patients with heart failure and wide QRS. However, it is still important to simplify patient selection and achieve a widely applicable parameter to better stratify patients who are candidates for CRT. METHODS: Eighteen patients (13 males, 5 females, mean age 67.5 +/- 7.2 years) with advanced heart failure due to ischemic (n = 12) or idiopathic dilated cardiomyopathy (n = 6) and complete left bundle branch block received biventricular pacing. The patients were considered eligible in the presence of echocardiographic evidence of intra- and interventricular asynchrony, defined on the basis of LV electromechanical delay. Investigations were performed before pacemaker implantation (at baseline), the day after, and 3 and 6 months later. RESULTS: Two patients died before the first outpatient examination. There were 15 (83%) responders to reverse remodeling among the remainder. In the overall population, there was a significant and progressive improvement in LV sphericity indexes, ejection fraction, mitral regurgitation area and LV volumes (p < 0.001). The improvement in the interventricular mechanical delay after CRT was significantly correlated with the decrease in LV end-systolic volume (r2 = 0.2558, p = 0.04). CONCLUSIONS: CRT reduces LV volumes in patients with advanced heart failure, complete left bundle branch block and detailed documentation of ventricular asynchrony prior to therapeutic pacing. Broadly applicable Doppler echocardiographic measures may increase the specificity of the long-term response to CRT in terms of LV performance.