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。     

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.     

Prevalence of dyssynchrony derived from echocardiographic criteria in heart failure patients with normal or prolonged QRS duration

Cardiac resynchronization therapy (CRT) for heart failure is targeted at specific patients with mechanical dyssynchrony. We aimed to evaluate the prevalence of dyssynchrony in heart failure patients with either normal or prolonged QRS duration using Doppler imaging. Sixty heart failure patients with idiopathic dilated cardiomyopathy (30 with prolonged QRS duration 30 with normal QRS duration) underwent standard echocardiography and tissue Doppler imaging examinations. Difference between left and right ventricular pre-ejection intervals of more than 40 msec was considered a marker of interventricular dyssynchrony. Intraventricular dyssynchrony was defined as a delay of 60 msec between the time to peak velocities of the septum and left ventricular lateral wall. Patients who have either intra- or interventricular dyssynchrony were defined as with cardiac dyssynchrony. Dyssynchrony was observed in 7 (23.3%) heart failure patients with normal QRS duration versus 26 (86.7%) patients with prolonged QRS duration. There was significant difference between the prevalence of dyssynchrony derived from echo criteria in two groups (P<0.05). Although patients with prolonged QRS duration have a high prevalence of dyssynchrony, yet some still have good cardiac synchronicity. Moreover, dyssynchrony also exists in a small percentage of heart failure patients with normal QRS duration. To identify the potential responders for CRT, both QRS duration and cardiac synchronicity should be assessed.     

Relation of left ventricular systolic dyssynchrony in patients with heart failure to left ventricular ejection fraction and to QRS duration

Left ventricular (LV) systolic dyssynchrony is an important pathologic mechanism in patients with heart failure (HF). However, the prevalence of intraventricular dyssynchrony in patients with different LV ejection fractions (EFs) is unknown. This study evaluated 402 consecutive patients with HF (mean age 64.99 +/- 13.15 years, 72.4% men) and 120 healthy controls. Dyssynchrony indexes included the SD of the time to peak systolic velocity (Ts) in ejection phase in the 12-segmental model (Ts-SD) and the difference in Ts between basal septal and basal lateral segments (Ts-Septal-Lateral) using tissue Doppler imaging. Patients were divided into 3 groups according to LVEF (LVEF <20%, >20% to 35%, and >35% to 50%) and compared with healthy controls. Both indexes were significantly higher in all 3 LVEF groups compared with controls (p <0.0001). Based on the established cut-off values, systolic dyssynchrony was equally prevalent in all 3 LVEF groups and was 67%, 62%, and 55% using Ts-SD and 38%, 36%, and 35% using Ts-Septal-Lateral, respectively. However, the prevalence of systolic dyssynchrony was higher using Ts-SD than Ts-Septal-Lateral (chi-square = 94.43, p <0.001). Conversely, the prevalence of electrical dyssynchrony, defined as a >120-ms QRS duration, decreased significantly with increasing LVEF (44%, 35%, and 16%; chi-square 5.60, p <0.001). In conclusion, the prevalence of mechanical systolic dyssynchrony was independent of severity of LV systolic dysfunction. This may implicate the potential role of cardiac resynchronization therapy for those with LVEF of 35% to 50%, in particular when systolic dyssynchrony is present.     

心电图QRS间期与慢性心力衰竭左心室同步性关系的超声评价

目的评价心电图QRS间期与慢性心力衰竭（心衰）左心室同步性的关系。方法对54例慢性心衰患者（宽QRS组28例，正常QRS组26例）和15例健康人（对照组）进行心肌组织多普勒成像研究，测量收缩期和舒张早期12节段达峰时间（Ts和Te），评价不同QRS间期的慢性心衰左心室各节段不同步状况以及左心室不同步的主要影响因素。结果慢性心衰舒张末期和收缩末期容积增大，宽QRS组较正常QRS组更加显著，12节段平均Ts显著增大。以Ts≥182ms作为分界值，正常QRS组46％、宽QRS组71％存在收缩期不同步。宽QRS组Te最大差值（Te-diff）最大，以Te-diff≥79ms作为分界值，正常QRS组58％、宽QRS组89％存在舒张期不同步。同时存在收缩期和舒张期不同步者，正常QRS组为31％，宽QRS组为64％。收缩末期容积与左心室收缩期不同步相关，舒张末期容积与舒张期不同步相关。结论心电图QRS间期不能完全反映慢性心衰左心室同步性状况，左心室收缩末期容积和舒张末期容积直接影响左心室的收缩期和舒张期同步性。     

Fragmented narrow QRS complex: Predictor of left ventricular dyssynchrony in non-ischemic dilated cardiomyopathy

BackgroundCardiac resynchronization therapy is an important therapeutic modality in drug refractory symptomatic patients of heart failure with wide QRS (≥120 ms) on electrocardiogram. However, wide QRS (considered as a marker of electrical dyssynchrony) occurs in only 30% of heart failure patients, making majority of drug refractory heart failure patients ineligible for resynchronization therapy. Significant numbers of patients with narrow QRS have echocardiographic evidence of left ventricular dyssynchrony. However, there is sparse data about additional features on the surface ECG which can predict intraventricular dyssynchrony. This study was undertaken to assess the utility of fragmented narrow QRS complex to predict significant intraventricular dyssynchrony in symptomatic patients of non-ischemic dilated cardiomyopathy.Method100 symptomatic patients of non-ischemic dilated cardiomyopathy with narrow QRS complexes (50 each with fragmented and normal QRS) were recruited. Tissue Doppler imaging was used to assess intraventricular dyssynchrony as per ‘Yu index’.Results78% patients (n = 39) in fQRS complex group and 14% (n = 7) in normal QRS complex group had significant intraventricular dyssynchrony (χ² = 20.61; p < 0.000005). fQRS complexes had 84.78% sensitivity, 79.62% specificity, a positive predictive value of 78% and negative predictive value of 86% to detect intraventricular dyssynchrony. fQRS also had sensitivity and specificity of 93% and 90% respectively to localize the dyssynchronous segment.ConclusionfQRS is a marker of electrical dyssynchrony, which results in significant intraventricular dyssynchrony in patients of non-ischemic dilated cardiomyopathy and a narrow QRS interval. fQRS localizes the dyssynchronous segment and might be useful in identifying patients who can benefit from cardiac resynchronization therapy.     

Benefit of cardiac resynchronization therapy to a patient with a narrow QRS complex and ventricular dyssynchrony identified by tissue synchronization imaging.

This report described an 81-year-old woman with severe symptomatic heart failure, reduced ejection fraction, mitral regurgitation, and an electrocardiographic QRS width of 118 ms who had ventricular dyssynchrony identified by echocardiographic tissue synchronization imaging. Because of her severe heart failure symptoms on maximal medical therapy, referral to implant a defibrillator, and mechanical dyssynchrony, she underwent cardiac resynchronization-defibrillator therapy with lateral left ventricular lead placement. This resulted in an immediate 30% increase in stroke volume and 35% decrease in mitral regurgitation. Echocardiographic tissue synchronization imaging may play a role in identifying mechanical dyssynchrony in patients with narrow QRS duration who may potentially benefit from cardiac resynchronization therapy.     

Mechanical dyssynchrony assessed by tissue Doppler imaging is a powerful predictor of mortality in congestive heart failure with normal QRS duration.

OBJECTIVES: We sought to test whether the mechanical dyssynchrony assessed by tissue Doppler imaging (TDI) is a predictor of cardiac events in patients with congestive heart failure (CHF) and QRS duration < or =120 ms. BACKGROUND: The prevalence and prognostic value of mechanical dyssynchrony in patients with CHF and normal QRS duration have not been well clarified. METHODS: A total of 106 patients (age 63 +/- 11 years) with CHF and ejection fraction (EF) <35% were followed serially; TDI was performed using four basal and four mid-left ventricular segments to assess the time to peak systolic point from R-wave on electrocardiogram (Ts). The standard deviation of Ts (Ts-SD) and the maximal temporal difference of Ts (Ts-diff) of eight segments were used as an indicator of mechanical dyssynchrony. Clinical events included readmission due to worsening of CHF, cardiac transplantation, and death. RESULTS: After 17 +/- 11 months of follow-up, the clinical event rate was 33% including all-cause mortality of 19%. Prolonged Ts-SD (>37 ms) and Ts-diff (>91 ms) were associated with a significant increase in all clinical events. By multivariate analysis, Ts-diff (>91 ms) was an independent risk factor of clinical events and mortality regardless of age, EF, QRS duration, and use of beta-blocking agents. Mean event-free survival was 16.3 months (95% confidence interval [CI] 11.9 to 20.7) in patients with Ts-diff >91 ms and 31.6 months (95% CI 28.0 to 35.1) in those with Ts-diff < or =91 ms, respectively (p < 0.001). CONCLUSIONS: Myocardial dyssynchrony assessed by TDI is a powerful predictor of clinical events in CHF with normal QRS.     

Evidence of left ventricular dyssynchrony resulting from right ventricular pacing in patients with severely depressed left ventricular ejection fraction.

AIMS: Cardiac resynchronization therapy (CRT) has recently emerged as an effective treatment for patients with moderate-to-severe systolic heart failure and left bundle branch block (LBBB). Right ventricular pacing (RVP) leads to an LBBB-like pattern in the electrocardiogram. The aim of this study was to evaluate the frequency of ventricular mechanical dyssynchrony in patients induced by RVP. METHODS AND RESULTS: The study included 33 patients with a conventional single or dual chamber pacemaker, 18 with ejection fraction (EF) > 35% and 15 with EF < or = 35%. In all patients, an intrinsic rhythm without intraventricular conduction delay (QRS < or = 120 ms) was present without RVP. Two-dimensional and Doppler echocardiographic criteria for mechanical dyssynchrony [aortic pre-ejection delay (APE), interventricular mechanical delay (IVMD), delayed activation of the posterior left ventricular wall (PD), septal-to-posterior wall motion delay (SPWMD)] were evaluated in all patients with and without RVP. QRS duration showed no difference between the two EF-groups without RVP (93 +/- 10 vs. 96 +/- 9 ms), but was significantly longer in patients with low EF with RVP (152 +/- 18 vs. 181 +/- 18 ms; P < 0.001). In patients with EF > 35%, only APE was slightly prolonged by RVP (111 +/- 20 vs. 129 +/- 17 ms; P = 0.03), whereas in patients with EF < or = 35% marked pathological differences in APE (118 +/- 29 vs. 169 +/- 24 ms; P < 0.001), IVMD (22 +/- 17 vs. 58 +/- 14 ms; P < 0.001), SPWMD (103 +/- 28 vs. 125 +/- 29 ms; P = 0.004), and PD (-21 +/- 25 vs. - 39 +/- 25 ms; P = 0.005) were found. A significant correlation between QRS duration and mechanical ventricular dyssynchrony was only found for two echocardiographic parameters (IVMD, APE) with RVP. CONCLUSION: In patients with a conventional pacemaker, mechanical dyssynchrony with RVP was shown exceptionally in patients with preserved or moderately depressed systolic left ventricular (LV) function, but in nearly all patients with severely depressed systolic LV function. These patients might benefit from CRT when frequent RVP is required.     

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。     

Prevalence of left ventricular dyssynchrony in patients with heart failure assessed by a novelprogrammer-cardioGRAF

Objectives Left ventricular systolic dyssynchrony is the most important determinant of response to cardiac resynchronization therapy （CRT）, playing a vital role to predict improvement of systolic function or LV reverse remodeling. CardioGRAF is a novel programmer based on the ECG gated single photon emission computed tomography （G-SPECT） imaging to detect LV systolic and diastolic dyssynchrony simultaneously. This study was to investigate the prevalence of systolic and diastolic left ventricular （LV） dyssynchrony in patients with heart failure. Methods We retrospectively studied 69 patients with heart disease, including 31 patients who had symptoms of heart failure （NYHA class Ⅱ-Ⅲ）, and 38 patients who had no symptoms of heart failure. （NYHA class Ⅰ）. G- SPECT data were analyzed by cardiaGRAF, and measurements included the time to end systole （TES）, the time to peak ejection （TPE）, the time to peak filling （TPF）, TES＋TPF and maximal difference （MD） of each parameters were obtained, using the 95th percentile of the control group as a cutoffof 150 ms for MD-TES, 139 ms for MD-TPE, 345 ms for MD-TPF and 315 ms for MD-TES＋TPF. Results The prevalence of LV systolic dyssynchrony was significantly higher in heart failure patients with reduced LV ejection fraction （LVEF）〈45% （72% for MD-TES; 64% for MD-TPE） compared with heart failure patients with preserved LVEF=45% （14% for both MD-TES and MD-TPE; P=0.002, P=0.005, respectively）; The prevalence of MD-TES〈150 ms was higher in NYHA class Ⅲ patients （64%） compared with NYHA class Ilpatients （27%, P=0.049）. However, the prevalence of the LV diastolic dyssynchrony were high but not difference between NYHA class III（47% for both MD-TPF and MD-TES＋TPF） and class Ⅲ（63% for MD-TPF; 69% for MD-TES＋TPF; P=NS） patients as well as between patients with preserved LVEF （43% for both MD-TPF and MD-TES＋TPF） and patients with reduced LVEF（64% for MD-TPF; 72% for MD-TES＋TPF; P=NS）. Conclusions The prevalence of LV systolic dyssynchrony was high in heart failure patients with reduced LVEF. Diastolic dyssynchrony was common in patients with heart failure. CardioGRAF maybe a useful method to detect LV dyssynchrony （J Gerlatr Cardio12009; 6：151-156）.     

Impact of heart rate on mechanical dyssynchrony and left ventricular contractility in patients with heart failure and normal QRS duration

AIMS: The quantification of mechanical dyssynchrony has important diagnostic value and may help to determine optimal therapy in heart failure (HF). We hypothesized that mechanical dyssynchrony may be augmented at increased heart rates in patients with HF and normal QRS duration. METHODS AND RESULTS: From online segmental conductance catheter signals, we derived indices to quantify temporal and spatial aspects of mechanical dyssynchrony during systole in 20 control subjects, 20 HF patients with normal QRS duration, and 12 HF patients with complete left bundle branch block (CLBBB). Data were collected at baseline, and then following a 40 bpm increase in heart rate induced by right atrial pacing. Mechanical dyssynchrony in HF patients with normal QRS duration or CLBBB was higher than that found in control subjects. In HF patients with normal QRS duration, mechanical dyssynchrony increased from 37.4+/-4.8% at baseline to 43.2+/-4.4% with increased heart rate (p<0.01), the resultant degree of mechanical dyssynchrony was similar to that at baseline in the HF patients with CLBBB. Increased heart rate did not affect dyssynchrony in the control patients. CONCLUSION: Mechanical dyssynchrony was augmented as heart rate increased by right atrial pacing in patients with HF and normal QRS duration.     

QRS波群记分法评价急性心肌梗死的左心室功能

为探讨常规心电图QRS波群记分法评价急性心肌梗死左心室功能的价值,分析90例急性心肌梗死患者的ORS波群与平衡法核素心血池测得的反映左心室功能参数的相关性。结果发现QRS波群记分与LVEF、PER、PFR、EF/3、FR/3、ER/3及FF/3呈显著负相关。说明QRS波群记分法可用于评价急性心肌梗死左心室功能。     

Comparison of serial measurements of infarct size and left ventricular ejection fraction by contrast-enhanced cardiac magnetic resonance imaging and electrocardiographic QRS scoring in reperfused anterior ST-elevation myocardial infarction

Background

Left ventricular ejection fraction (LVEF) is a powerful prognostic marker after acute myocardial infarction and is dependent on infarct magnitude. Contrast-enhanced cardiac magnetic resonance (ceCMR) represents the current criterion standard means of LVEF and infarct size measurement. Infarct size and LVEF can be estimated from the 12-lead electrocardiogram (ECG) using the Selvester QRS score. We examined for the first time the relationship between serial measures of LVEF and infarct size by ceCMR and ECG in patients with reperfused anterior ST-elevation myocardial infarction (STEMI) and depressed LVEF.

Methods

Thirty-four patients (mean ± SD age, 59 ± 11.8 years; 70.6% male) underwent ceCMR and simultaneous ECG at mean 93 hours after admission and at 12 and 24 weeks. The QRS score was calculated on each ECG, from which infarct size and LVEF were estimated and compared with the equivalent ceCMR measurements.

Results

Infarct size on ceCMR was higher than that by QRS score at each time-point (P < .001) with modest correlation (r = 0.56-0.78, P < .001). Left ventricular ejection fraction was consistently significantly higher on CMR than on ECG, with weak correlation (r = 0.37-0.51, P < .05). We derived a novel equation relating QRS score to CMR-measured LVEF in the subacute phase of infarction: LVEF = 61 − (1.7 × QRS score) (%).

Conclusions

In patients with reperfused anterior ST-elevation myocardial infarction and depressed LVEF, ceCMR is moderately correlated with the QRS in the serial measurement of infarct size and LVEF. Infarct size (measured by ceCMR) and LVEF are consistently higher than those calculated on the QRS score in the acute and subacute phases of infarction.     

心力衰竭患者QRS波间期与心脏机械收缩功能失同步化的相关性研究

目的评价充血性心力衰竭(CHF)患者QRS间期与左右心室间、左心室内不同步运动参数的相关关系。方法 81例CHF患者及26名健康体检者作为对照组纳入本研究。行常规及彩色组织多普勒显像(TDI)检查。以左、右心室问收缩延迟(IVMD)>33ms定义室间不同步运动,以二尖瓣环6位点中任意2点QRS波起始至心室收缩顶峰的间期(TsP)最长延迟>121ms,或6位点TsP的标准差(TsP-SD)>47ms定义左心室内收缩不同步。比较QRS≥120 ms与QRS<120ms的CHF患者室间、室内不同步发生率,分析QRS间期与室间、室内不同步参数的相关关系。结果 CHF患者IVMD较对照组明显延长[(25.7±16.3)ms比(12.8±8.8)ms,P<0.0001],IVMD与QRS间期呈明显正相关(r=0.44,P<0.0001)。CHF伴QRS≥120ms(n=31)者室间不同步发生率明显高于CHF伴QRS<120ms者(n=50)(66.7%比20.9%,P<0.05)。CHF患者TsP最长延迟及TsP-SD较对照组明显延长,TsP最长延迟及TsP-SD与QRS间期呈弱相关。结论 CHF患者室间不同步运动发生率明显高于对照组,ORS间期增宽与室间不同步的关系可能更密切。     

fQRS as a marker of granulomatous disease in patients presenting with ventricular tachycardia and normal left ventricular ejection fraction

Background

Granulomatous myocarditis may present with sustained monomorphic ventricular tachycardia (SMVT) in the presence of normal left ventricular ejection fraction (LVEF), and could be mistaken for idiopathic ventricular tachycardia (IVT). The use of cardiac imaging for diagnosis can be limited by availability and high cost. ECG is readily available and inexpensive. Fragmented QRS (fQRS) on ECG has been found to be associated with myocardial scar. We hypothesized that fQRS could be useful in the diagnosis of granulomatous VT (GVT).

Methods

We compared the 12-lead ECG of 16 patients with GVT and 42 patients with IVT who presented with SMVT.

Results

The presence of fQRS was significantly higher in the GVT group compared to the IVT group (75% versus 19.1%, p < 0.001). The location of fQRS correlated with delayed enhancement cardiac magnetic resonance imaging (DE-CMR) in the same segment in 4/16 patients in the GVT group. It correlated with an affected segment on either DE-CMR or 18FDG positron emission computed tomography in 4/11 patients in the GVT group who had both imaging modality. Whenever fQRS was present in contiguous leads other than the inferior leads, it always corresponded to an affected segment on imaging.

Conclusions

In patients presenting with SMVT and no structural heart disease, the presence of fQRS is strongly associated with granulomatous myocarditis. fQRS on the surface ECG is a helpful tool the presence of which should prompt a CMR for a definitive diagnosis.     

Risk and predictors of dyssynchrony cardiomyopathy in left bundle branch block with preserved left ventricular ejection fraction

BackgroundLeft bundle branch block (LBBB) and left ventricular (LV) dyssynchrony likely contribute to progressive systolic dysfunction. The evaluation of newly recognized LBBB includes screening for structural heart abnormalities and coronary artery disease (CAD). In patients whose LV ejection fraction (EF) is preserved during initial testing, the incidence of subsequent cardiomyopathy is not firmly established.HypothesisThe risk of developing LV systolic dysfunction among LBBB patients with preserved LVEF is high enough to warrant serial imaging.MethodsWe screened records of 1000 consecutive patients with LBBB from our ECG database and identified subjects with an initially preserved LVEF (≥45%) without clinically relevant CAD or other cause for cardiomyopathy. Baseline imaging, clinical data, and follow‐up imaging were recorded to determine the risk of subsequent LV systolic dysfunction (LVEF ≤40%).Results(Data are mean + SD) 784 subjects were excluded, the majority for CAD or depressed LVEF upon initial imaging. Of the remaining 216, 37 (17%) developed a decline in LVEF(≤40%) over a mean follow‐up of 55 ± 31 months; 94% of these patients had a baseline LVEF≤60% and LV end systolic diameter (ESD) ≥ 2.9 cm indicating that these measures may be useful to define which patients warrant longitudinal follow‐up. The negative predictive value of a LVEF>60% and LVESD <2.9 cm was 98%.ConclusionsSeventeen percent of patients with LBBB and initial preserved LVEF develop dyssynchrony cardiomyopathy. We believe the risk of developing dyssynchrony cardiomyopathy is high enough to warrant serial assessment of LV systolic function in this high‐risk population.     

心肌血运重建术前后运动试验QRS时限与室性心律失常的关系

目的 探讨冠心病患者血运重建术前后运动试验ＱＲＳ时限的变化及其与室性心律失常的关系。方法 观察６６例伴或不伴有严重室性心律失常的冠心病患者运动试验前后ＱＲＳ时限、ＱＴ离散度和ＳＴ段的变化以及冠状动脉血运重建术后上述各指标的改变。结果 运动后两组ＱＲＳ时限均显著延长（Ｐ〈０．０１）,其延长程序与ＱＴ离散度增大和ＳＴ段压值值之间呈良好正相关（Ｐ〈０．０１）,其中室性心律失常组的ＱＲＳ延长和ＱＴ离散度增