12导联心电图对扩张型心肌病致慢性心力衰竭患者预后的评估价值观察

目的探究12导联心电图对扩张型心肌病(DCM)致慢性心力衰竭患者的预后评估价值。方法回顾性分析2017年1月-2019年1月期间就诊的DCM致慢性心衰患者80例的临床资料、检查方法以及随访终点事件。结果(1)随访时间6-30个月,80例患者中,全因死亡21例,死亡率26.25%。(2)以QRS时限≥120ms分组,80例患者被分为A组(QRS时限≥120ms,26例)与B组(QRS时限<120ms,54例),A组患者的全因死亡率(69.23%)高于B组(5.56%)(P<0.05)。结论12导联心电图能为评估患者DCM致慢性心衰预后提供依据,其应用价值较高,值得推广。     

心电图异常对预测扩张型心肌病致慢性心力衰竭患者的预后意义

目的:评价12导联心电图对扩张型心肌病致慢性心力衰竭(心衰)患者预后的预测作用。方法:前瞻性、多中心随访787例扩张型心肌病致慢性心衰患者。通过门诊随诊或电话、信件随访慢性心衰患者的终点事件。用Cox风险比例回归分析确定全因死亡的独立预测因子,对QRS时限是否大于120 ms等心电图指标用Kaplan-Meier曲线进行生存分析(log-rank检验)。结果:随访过程中203例死亡。经Cox回归分析发现心房颤动与全因死亡有关[风险比(HR)=2.064;95%可信区间(CI):1.102~3.864,P0.05];非持续性室性心动过速与全因死亡有关[HR=3.887;95%CI:1.554~9.724,P0.05];QRS时限与全因死亡有关[HR=1.010;95%CI:1.002~1.018,P0.05]。Kaplan-Meier生存曲线分析显示,以QRS时限分层,不同水平的QRS时限其生存率之间的差异具有统计学意义(P0.05)。结论:对扩张型心肌病致慢性心衰患者生存率有影响的心电图指标是心房颤动、非持续性室性心动过速和QRS时限;不同水平QRS时限与生存率之间存在显著差异。     

QRS波时限对肺心病患者短期预后的判断

目的探讨QRS波时限对肺心病患者短期预后的影响。方法收集两家医院住院诊断慢性肺源性心脏病患者252例,分为QRS波时限正常组(192例,QRS波时限≤120ms)、QRS波时限延长组(60例,QRS波时限120ms),收集所有患者临床血清生化、心脏超声等结果及临床事件资料,统计分析比较两组临床资料结果及心衰加重、致命性心律失常和心源性死亡等不良心血管事件的发生率。结果 QRS波延长组患者心衰加重、致命性心律失常和心源性死亡比例、血浆N末端B型利钠肽原(NT-proBNP)水平、左室舒张末内径(LVEDd)值均较QRS波正常组显著升高(p0.05)。结论心电图QRS波时限与肺心病患者心衰加重、致命性心律失常和心源性死亡的心血管不良事件相关,临床可将其作为肺心病患者评估短期预后的指标之一。     

应用组织多普勒成像评价不同QRS时限心力衰竭患者的心室同步性

目的 应用组织多普勒技术评价不同QRS时限心力衰竭(心衰)患者心室收缩的同步性.方法 选择48例心衰患者(心衰组),其中QRS时限≤120 ms者25例(QRS时限≤120 ms心衰组),QRS时限＞120 ms者23例(QRS时限＞120 ms心衰组),以及25名正常人(对照组),测量左、右心室射血前间期并计算其差值(IVD);用组织多普勒技术测量12节段心肌收缩达峰时间(Ts),并计算(1)12节段Ts最大差值(Ts-diff),(2)12节段Ts的标准差(Ts-SD),(3)基底段室间隔及左室侧壁的Ts之差(S-LW-diff).结果 QRS时限≤120 ms心衰组、QRS时限＞120 ms心衰组和对照组IVD分别为31.00±15.21 ms、61.33±27.67 ms和15.89±7.56 ms,Ts-diff分别为70.29±35.25 ms、98.07±46.04 ms和47.86±16.78 ms,Ts-SD分别为24.64±12.84 ms、33.61±15.58 ms和15.24±5.65 ms,S-LW-diff分别为54.28±20.81 ms、76.32±42.38 ms和32.62±20.34ms,两心衰组与对照组间差异均有统计学意义(均为P＜0.05).QRS时限≤120 ms心衰组和QRS时限＞120 ms心衰组患者中均存在收缩不同步(44.00%比95.65%,P＜0.05).结论 QRS时限正常的心衰患者中存在一定比例的收缩不同步,QRS时限增宽的心衰患者的不同步比例更高.     

心肌病猝死高危患者无创预警参数分析

目的:探讨心肌病猝死高危患者中有预测价值的无创性指标。方法:回顾性分析410例心肌病住院患者的恶性心律失常[室性心动过速(VT)或心室颤动(VF)]发生率及左室射血分数(LVEF),并随访调查心源性猝死(SCD)的发生情况。测量其中心电图记录清晰的200例患者(心肌病组)的心电图参数QRS时限、QT间期和Tp-Te间期,计算QTc。取80例健康者作为心电图参数对照组,比较2组QTc分布情况。根据QRS时限将上述200例患者分为QRS≥120ms(75例)和QRS<120ms(125例)。根据LVEF值将410例患者分为30%≤LVEF≤35%(207例),35%50%(18例)。分别对无创性指标LVEF、QTc、Tp-Te、QRS与VT/VF、SCD发生的关系进行分析。结果:410例中,245例(59.8%)发生心律失常,其中心房颤动102例(24.9%),VT/VF 54例(13.2%),Ⅰ度房室传导阻滞15例(3.7%),Ⅱ～Ⅲ度房室传导阻滞15例(3.7%),其余并发房性期前收缩或室性期前收缩共59例(14.4%)。心肌病组中QTc≥460ms者所占比例明显高于对照组(22.0%:7.5%,P<0.01);Tp-Te与QTc呈正相关(P=0.009);QRS≥120ms者的SCD发生率比QRS<120ms者明显增加(32.0%:18.4%,P<0.05)。随着LVEF降低,SCD发生率有增高趋势,但均差异无统计学意义。结论:高度房室传导阻滞、VT/VF是心肌病高发SCD的常见原因。QTc≥460ms和Tp-Te延长、QRS≥120ms是预测心肌病患者SCD发生的有效参数;LVEF可能具有预测心肌病患者发生VT/VF的潜在价值。     

晚期扩张型心肌病患者QRS波时限与心脏机械同步性的相关性研究

目的评价晚期扩张型心肌病患者QRS波时限是否与心脏机械同步性相关。方法非连续入选晚期扩张型心肌病患者30例,按QRS波时限分为窄QRS组(QRS波时限<120 ms)及宽QRS组(QRS波时限≥120 ms),采用GE Vivid7彩色超声诊断仪应用组织多普勒显像技术测量:①室间机械延迟(IVMD);②室内同步性指数(TSI)并观察③收缩最延迟的部位,比较两组差异。结果窄QRS组的IVMD较宽QRS组窄(为11.5±8.2ms vs40.6±16.7ms,P=0.006),TSI两组无差异(88.6±35.9 ms vs 117.2±40.8 ms,P=0.09)。宽QRS组半数存在室间不同步,而窄QRS组则无室间不同步。宽、窄QRS组室内不同步的比例分别为71.4%、87.5%,两者无差别。收缩最延迟的部位可见于后间隔、侧壁、后壁及下壁,各自占38.6%、23%、23%及15.4%。结论晚期扩张型心肌病患者QRS波时限与室内同步性不直接相关,但宽QRS波患者较常存在左右室间收缩的不同步。收缩最延迟部位因人而异。     

单中心左室射血分数小于等于0.35患者宽QRS波时限比例调查及相关因素分析

目的了解国内心力衰竭(简称心衰)患者具有心脏再同步化治疗(CRT)适应证的比例,为进一步有的放矢的更好开展CRT工作提供相关的临床依据。方法连续入选本院门诊或病房就诊的超声心动图测量左室射血分数(LVEF)≤0.35患者,收集其临床资料并同时行12导联心电图检查,测得QRS波群时限,并将心电图表现与患者临床资料进行对比分析。结果 1共入选451例,以扩张型心肌病最常见,占80.3%。2QRS波时限≥120 ms147例(占32.6%),其中,QRS波时限≥120 ms心电图表现类型为左束支阻滞84例(18.6%),心室内阻滞44例(9.8%),右束支阻滞19例(4.2%)。3年龄段30岁、30~39岁、70~79岁、≥80岁QRS波时限与性别无差异,而40~49岁、50~59岁及60~69岁年龄段,女性宽QRS波的比例高于男性。4将QRS波时限分为120 ms、120~135 ms和≥135 ms三组,显示QRS波时限与左室舒张末内径(LVEDD)存在正相关。5QRS波时限与NYHA心功能分级显著相关,QRS波时限越宽,心功能越差。6QRS波时限与LVEF值(分为0.20,0.20~0.30及≥0.30)呈负相关(r=-0.1402,P=0.0028)。结论国内心衰患者存在CRT适应证者的比例并不低,QRS波时限与左室内径、心功能及LVEF值显著相关。     

收缩性心衰患者心律失常及心电图变化分析

背景：心衰常伴随各种房性和室性心律失常的发生。目的：本研究的目的是观察收缩性心衰患者心律失常发生情况并分析各项心电图指标。方法：回顾性分析我院住院的收缩性心衰患者病历资料,选取我院住院期间94名左室射血分数(LVEF)＜50%的心衰患者。我们根据患者射血分数将患者分为两组：LVEF≤35%,LVEF＞35%,并分析患者住院资料,提取12导联心电图心律失常和心电图异常情况,实验室检查等指标。结果：纳入收缩性心衰患者94名,其中LVEF≤35%患者31名。常见的伴随疾病包括高血压52.1%,糖尿病29.8%,冠脉疾病25.5%,扩张性心肌病23.4%,慢性肾脏病12.8%,卒中9.5%。心电图分析发现：24.7%的患者有心动过速,23.7%的患者QRS＞120ms,51.1%的患者矫正QT(QTc)间期延长(男性QTC>440ms,女性>460ms)。 最常见的心律失常房颤,室早各占26.8%和25.8%,房颤患者中,快室率占32%。另外好发的心律失常中房早占18.3%、窦性心动过速占16.1%、右束支传导阻滞(RBBB)占7.5%、左束支传导阻滞(LBBB)占5.3%。与另一组相比,严重收缩性心衰患者(LVEF≤35%)QRS波时限(P<0.001)和QTc(P=0.008)间期明显延长。结论：收缩性心衰患者最常见的心律失常为房颤和室早,并且QRS波时限和QTc间期明显延长。     

心电图对陈旧性心肌梗死风险评估的价值探讨

目的通过对陈旧性心肌梗死（OMI）患者碎裂QRS波（fQRS）、病理性Q波及其与室性心律失常的发生情况进行分析,探讨fQRS及病理性Q波与室性心律失常的关系,以评估心电图对陈旧性心肌梗死风险的预测价值。方法对335例确诊陈旧性心肌梗死的患者进行动态心电图检查,将OMI伴单纯fQRs波患者分为前壁组（61例）、下壁组（40例）和侧壁组（15例）,并对各组间室性心律失常发生率进行比较分析;根据fQRS波时限,将OMI伴fQRs波患者分为fQRS≥110ms组（36例）、fQRS〈110ms（156例）,并对两组间室性心律失常发生率进行对比分析;根据病理性Q波QRS波群时限,将OMI伴病理性Q波患者分为QRS≥110ms组（21例）、QRS〈110ms（75例）,并对两组间室性心律失常发生率进行对比分析。结果OMI伴单纯fQRs波患者不同部位间室性心律失常发生率无明显差异（P均〉0．05）;OMI伴fQRs波患者fQRS≥110ms组室性心动过速发生率明显高于fQRS〈110ms组（P=0．026）;OMI伴病理性Q波患者QRS≥110ms组成对室性期前收缩（P=0．045）发生率明显高于QRS〈110ms组。结论OMI患者fQRs时限越长,发生室性心动过速的风险越高;OMI患者QRS波时限越长,发生成对室性期前收缩的风险越高,QRS时限是OMI患者室性心律失常预警的心电图指标。     

应用超声多普勒评价不同QRS时限心力衰竭患者的收缩同步性

目的应用常规超声和组织多普勒技术评价收缩不同步在QRS时限正常及增宽的心力衰竭患者中的发生率。方法选择60例纽约心脏病学会(NYHA)分级心功能Ⅲ级的扩张型心肌病患者,其中QRS时限≤120ms者30例,QRS时限>120ms者30例,均接受常规超声和组织多普勒检查。以左、右心室射血前间期之差>40ms作为室间收缩不同步的指标。应用组织多普勒技术分别测量室间隔和左心室侧壁基底部心肌达到收缩峰值的时间,二者时差>60ms定义为室内收缩不同步。满足室间、室内收缩不同步标准任一项即视为存在收缩不同步。结果QRS时限≤120ms的心力衰竭患者中有23.3%存在收缩不同步,而QRS时限>120ms者中不同步比例高达86.7%,二者差异有统计学意义(P<0.01)。未发现QRS时限与超声证实的收缩不同步间存在相关性(P=0.112)。结论尽管QRS时限增宽心力衰竭患者的不同步比例很高,但仍有一定比例的患者同步性尚好。同时,亦有一定比例的QRS时限正常者存在收缩不同步。     

Comparison of outcomes for patients with nonischemic cardiomyopathy taking intravenous inotropes versus those weaned from or never taking inotropes at cardiac resynchronization therapy

Mixed cohorts of patients with ischemic and nonischemic end-stage heart failure (HF) with a QRS duration of ≥120 ms and requiring intravenous inotropes do not appear to benefit from cardiac resynchronization therapy (CRT). However, CRT does provide greater benefit to patients with nonischemic cardiomyopathy and might, therefore, be able to reverse the HF syndrome in such patients who are inotrope dependent. To address this question, 226 patients with nonischemic cardiomyopathy who received a CRT-defibrillator and who had a left ventricular ejection fraction of ≤35% and QRS of ≥120 ms were followed up for the outcomes of death, transplantation, and ventricular assist device placement. Follow-up echocardiograms were performed in patients with ≥6 months of transplant- and ventricular assist device-free survival after CRT. The patients were divided into 3 groups: (1) never took inotropes (n = 180), (2) weaned from inotropes before CRT (n = 30), and (3) dependent on inotropes at CRT implantation (n = 16). At 47 ± 30 months of follow-up, the patients who had never taken inotropes had had the longest transplant- and ventricular assist device-free survival. The inotrope-dependent patients had the worst outcomes, and the patients weaned from inotropes experienced intermediate outcomes (p <0.0001). Reverse remodeling and left ventricular ejection fraction improvement followed a similar pattern. Among the patients weaned from and dependent on inotropes, a central venous pressure <10 mm Hg on right heart catheterization before CRT was predictive of greater left ventricular functional improvement, more profound reverse remodeling, and longer survival free of transplantation or ventricular assist device placement. In conclusion, inotrope therapy before CRT is an important marker of adverse outcomes after implantation in patients with nonischemic cardiomyopathy, with inotrope dependence denoting irreversible end-stage HF unresponsive to CRT.     

Idiopathic dilated cardiomyopathy: prognostic significance of electrocardiographic and electrophysiologic findings in the nineties.

BACKGROUND: With the exception of a few cases such as aborted sudden cardiac death, sustained ventricular tachycardia, and syncope of unexplained origin, there is no consensus on the clinical findings identifying patients with idiopathic dilated cardiomyopathy with an increased risk of sudden cardiac death or malignant ventricular arrhythmias. METHODS: To verify whether electrocardiographic and arrhythmologic features could be useful for prognostic stratification, 78 consecutive patients with an invasive diagnosis of idiopathic dilated cardiomyopathy, but without symptomatic ventricular arrhythmias, were enrolled in a prospective study. Signal-averaged ECG, 24 to 48 hour ECG monitoring and electrophysiologic study were performed at the time of diagnosis to identify arrhythmogenic predictors of outcome. Transplant-free and arrhythmic event-free survival was evaluated on the basis of initial parameters. RESULTS: During a mean follow-up of 85 months, 9 patients died (6 of sudden cardiac death and 3 of congestive heart failure), 10 patients underwent cardiac transplantation for refractory heart failure, and 3 presented with sustained ventricular tachycardia. The independent predictors for death and cardiac transplantation were an HV interval > 55 ms and the combination of frequent repetitive ventricular ectopics with a poor left ventricular function. A strong index of arrhythmic events proved to be the association of a prolonged HV interval with a wide (> 110 ms) QRS complex (odds ratio 4.53, 95% confidence interval 1.57-13.04, p < 0.005). CONCLUSIONS: An accurate measurement of the HV interval and QRS duration at baseline evaluation may add prognostic information in patients with idiopathic dilated cardiomyopathy. In our experience, abnormal values of both parameters identified a group of patients with a very high risk of late occurring arrhythmic events.     

Kommentar zu den ESC-Leitlinien zur Device-Therapie bei Herzinsuffizienz 2010

As part of the 2010 focused update of ESC guidelines on device therapy in heart failure, the guidelines on pacemakers in the treatment of heart failure were renewed. A new feature is that cardiac resynchronization therapy (CRT) is indicated for New York Heart Association (NYHA) class III and IV irrespective of the presence of left ventricular dilatation and specified for NYHA class IV (patient ambulatory, stable, life expectancy >6 months). Furthermore, NYHA class II (but not class I) has been added when there is left bundle branch block and QRS duration ≥150 ms. CRT is also indicated for patients in NYHA class III-IV with permanent atrial fibrillation and heart failure [left ventricular ejection fraction (LVEF) ≤ 35%] when QRS is ≥ 130 ms and ventricular rate has slowed either spontaneously or by AV node ablation. In patients with heart failure (NYHA class II-IV, LVEF ≤ 35%) who need a pacemaker for AV block, CRT is generally indicated to avoid progression of heart failure caused by right ventricular stimulation, also in cases of intrinsic QRS <120 ms. For patients with terminal heart failure who are not eligible for heart transplantation, treatment with a left ventricular assist device can be performed as destination therapy. The new guidelines expand the indication for device therapy in heart failure based on the newest study findings, particularly for patients in NYHA class II, and specify the old guidelines. There are still uncertainties that must be investigated in randomized trials regarding patients with permanent atrial fibrillation, the indication for CRT in heart block, and the question of CRT with pacemaker or defibrillator.     

心力衰竭加重并左室射血分数降低患者的QRS时限与预后

目的观察住院期间QRs时限对心力衰竭并左室射血分数降低预后的影响。方法回顾性分析心力衰竭并左室射血分数降低（≤40％）或正常的住院患者住院期间的QRs波群时限。结果3002例患者纳入研究,其中正常QRS波群时限1745例（〈120ms）,QRS波群延长（≥120ms）1257例。平均随访10个月,基础QRS波群时限正常患者全因死亡率为18．8％,基础QRS波群延长患者为28．3％（nR。1．62,95％CIL38～1．88）。基础QRS波群正常患者心血管死亡和心力衰竭住院率为31．5％和35．8％,延长者则为39．0％和43．6％（朋=1．40、1．42;95％CIL25-1．60、1．18-1．72）。QRS波群时限延长与增加全因死亡率危险性相关（HR=1．25：95％C11．03～1．52）,并增加心血管死亡或心力衰竭住院率（HR=1．21、1．28,95％CIL10～1．40、1．12～1．38）。基础Qas波群延长患者最后住院心电图QRS波群正常者仅为4．0％。结论延长的QRS波群在LVEF降低患者中十分多见,是出院后高患病率和高死亡率的独立预测因素。     

Relationship between QRS duration and left ventricular dyssynchrony in patients with end-stage heart failure

INTRODUCTION: Patients with end-stage heart failure and a wide QRS complex are considered candidates for cardiac resynchronization therapy (CRT). However, 20% to 30% of patients do not respond to CRT. Lack of left ventricular dyssynchrony may explain the nonresponse. Accordingly, we evaluated the presence of left ventricular dyssynchrony using tissue Doppler imaging (TDI) in 90 consecutive patients with heart failure. METHODS AND RESULTS: Ninety patients with severe heart failure (left ventricular ejection fraction <35%, New York Heart Association class III-IV) were prospectively evaluated. Based on QRS duration, 30 consecutive patients with a narrow QRS complex were included (QRS duration 150 ms). All patients underwent TDI to assess left ventricular dyssynchrony. Extensive left ventricular dyssynchrony was defined as an electromechanical delay on TDI between the septum and lateral wall, the so-called septal-to-lateral delay, of >60 ms. Severe dyssynchrony was observed in 27% of patients with narrow QRS complex, 60% with intermediate QRS duration, and 70% with wide QRS complex. No relation existed between QRS duration and septal-to-lateral delay. CONCLUSION: From 30% to 40% of heart failure patients with QRS duration >120 ms do not exhibit left ventricular dyssynchrony, which may explain the nonresponse to CRT. Alternatively, 27% of patients with heart failure and a narrow QRS complex show significant left ventricular dyssynchrony and may be candidates for CRT.     

Cardiac resynchronization therapy in patients with narrow QRS

Conduction delay affecting 30-50% of patients with NYHA class III-IV heart failure (HF) mainly results from left bundle branch block and leads to deterioration of cardiac contractility through intra- and interventricular dyssynchrony. Cardiac resynchronization therapy (CRT) has class I recommendation for the treatment of patients with severe systolic HF who have left ventricular ejection fraction less or equal to 35%, QRS duration greater than or equal to 120 ms. Nevertheless some studies have shown that systolic asynchrony is present in 27-43% of HF patients with narrow QRS complexes (defined as <120 ms). We present here results of CRT in 20 patients (13 male, 7 female). Main indication for CRT was ventricular dyssynchrony during basic cardiac rhythm or cardiac pacing independently of QRS width. In 4 patients width of QRS complex was less than 120 ms, in 3 QRS varied from 120 to 149 ms pts and in 13 it was equal to or exceeded 150 ms. CRT in patients with narrow QRS resulted in clinical improvement associated with increase of cardiac contractility and decrease of left ventricular end systolic volume. This allows to conclude that CRT can be beneficial for HF patients with narrow QRS and ventricular dyssynchrony.     

REDUCED SYSTOLIC PERFOMANCE BY TISSUE DOPPLER IN PATIENTS WITH PRESERVED AND ABNORMAL EJECTION FRACTION: NEW INSIGHTS IN CHRONIC HEART FAILURE

Background: Identification of the responder candidates for multisite pacing is still difficult and severe heart failure, dilated left ventricle with reduced ejection fraction, prolonged QRS with left bundle branch block (LBBB) are still considered the principal indicators of ventricular desynchronization. The aim of the study was to assess if echographic ventricular desynchronization parameters measured in patients with dilated cardiomyopathy and severe heart failure are correlated with the duration of the QRS on surface electrocardiogram. Methods: This study included 51 patients aged 58.8 ± 7.4 years with idiopathic DCM. The following parameters were measured: QRS duration; effective contraction time (ECT) measured as the interval between QRS onset and closure of aortic valve, interventricular delay (IVD) measured as the time between onset of aortic and pulmonary flow, left ventricular mechanical delay (LVD) as the time from maximal interventricular septum contraction and posterior wall contraction, posterior (P), lateral (L), and posterolateral (PL) wall delays, as the time from QRS onset to maximal wall contraction. Regional post‐systolic contraction was defined in a given wall as the difference (contraction delay ? ECT)> 50 ms. Results: 29 patients presented complete LBBB, 22 patients had QRS duration < 120 ms. 39 patients had a post‐systolic contraction of the PL wall (32 patients of the L wall and 26 patients of the P wall). 16 patients with QRS duration <120 had a post‐systolic contraction of the PL wall (as for the LBBB the rest of 39 patients). In 40 patients the sequence of regional ventricular contraction was: P‐L‐PL wall (16 patients with QRS < 120). LVD was > 100 ms in 36 patients (26 patients with LBBB and 10 with QRS < 120). 27 patients with LBBB and 6 with QRS < 120 ms presented IVD > 30 ms. There was no correlation between the QRS duration and the parameters listed above. Conclusions: In a population of patients with severe heart failure and dilated cardiomyopathy there is no correlation between the duration of the QRS and echocardiographic parameters of ventricular desynchronization. These results show that mechanical ventricular desynchronization can be observed in patients with a QRS duration < 120 ms. Further studies are needed to evaluate if this population could beneficiate of multisite pacing therapy.     

Is Wider Worse? QRS Duration Predicts Cardiac Mortality in Patients with Right Bundle Branch Block

Background: Increasing QRS duration may be of prognostic significance in patients with right bundle branch block (RBBB) and may assist in predicting overall cardiovascular risk. Methods: To test this hypothesis, we examined the Computerized Patient Records of patients with complete and persistent RBBB. Primary and secondary end points were all‐cause and cardiac mortality. The effects of QRS duration on death rates were analyzed using the Cox proportional hazards regression model (P < 0.05). We identified 52,852 patients with EKGs and selected all those with diagnosis of RBBB (QRS ≥ 120 ms) between January 2000 and January 2004. Some patients had EKG records confirming RBBB since 1987. The QRS durations were categorized into four groups: 120–129, 130–139, 140–149, and ≥ 150 ms. Results: A total of 997 (1.9%) patients (mean age 68.9 ± 10 years) with RBBB were followed for 1–226 (median 45) months. All‐cause mortality occurred in 344 (34.5%), cardiac deaths in 59 (5.9%), noncardiac in 191 (19.2%), and unknown causes in 94 (9.4%) patients. Mean left ventricular EF for cardiac patients was 38 ± 15%. In patients with cardiac deaths, QRS duration was associated with increased morality (P < 0.007). For every 10 ms increase in QRS duration, the risk of death rose by 26.6%. The effect of QRS duration on all cause mortality was not statistically significant (P < 0.43). Conclusion: Increasing QRS duration was an independent predictor of cardiac mortality in patients with RBBB, but had no influence on all‐cause mortality. QRS duration has added prognostic information to the presence of right bundle branch block.     

Usefulness of prolonged QRS duration to identify high-risk ischemic cardiomyopathy patients with syncope and inducible ventricular tachycardia

We evaluated 61 consecutive patients who had coronary artery disease, decreased left ventricular function, and syncope and underwent implantation of a cardioverter-defibrillator because sustained ventricular tachycardia was inducible at electrophysiologic testing. During a follow-up of 3.0 +/- 1.8 years, 23 patients (38%) developed ventricular tachycardia. Prolonged QRS duration (>/=120 ms) was the only significant predictor of arrhythmia. The 1- and 2-year rates without ventricular arrhythmia were 82% and 77%, respectively, in patients whose QRS duration was <120 ms. In contrast, 1- and 2-year rates without ventricular arrhythmia were only 64% and 51%, respectively, in patients whose QRS duration was >/=120 ms (risk ratio 3.7, 95% confidence interval 1.4 to 9.8, p = 0.0092).     

Left ventricular dyssynchrony predicts benefit of cardiac resynchronization therapy in patients with end-stage heart failure before pacemaker implantation

We evaluated patients with end-stage heart failure who have a high likelihood of response to cardiac resynchronization therapy (biventricular pacing). It appears that 20% of patients do not respond to this expensive therapy despite the use of selection criteria (dilated cardiomyopathy, heart failure, New York Heart Association class II or IV, left ventricular ejection fraction <35%, left bundle branch block, and QRS >120 ms). The presence of left ventricular dyssynchrony is needed to result in improvement after cardiac resynchronization therapy.