超声评价LBBB对左室整体和局部活动的影响

目的　超声评价LBBB患者左室整体和局部活动。方法　超声测量 15例LBBB患者 (LBBB组 )和 15例正常人 (control组 )各瓣环 ,获得各时相的持续时间 (ICT、ET、IRT、DET) ,评价左室整体和局部Z指数 [(ET DFT) /R R],并测量等容收缩期波峰的加速时间 (IVA)、射血期波峰的加整时间 (Sac)、E波的减速时间 (Edc)。结果　LBBB患者左室整体和局部Z指数明显减低 ,各壁ICT明显延长 ;左室室间隔、下壁的IRT和IVA延长 ,DFT和Edc缩短 ,ICT/ET增加。结论　LBBB时室壁激动的异常 ,影响左室整体和局部舒缩活动     

定量组织速度成像对左束支传导阻滞左室收缩和舒张活动的评价

目的利用定量组织速度成像(QTVI)技术评价左束支传导阻滞左心室整体和局部收缩、舒张活动。方法测量20例完全性左束支传导阻滞(LBBB)患者和20名健康人于标准心尖四腔、两腔及心尖左室长轴切面获得的左心室6个室壁(后室间隔、侧壁、下壁、前壁、后壁、前间隔)基底段、中间段及心尖段同一心动周期各时相时间(ICT、IRT、ET等)以及长轴方向收缩期峰值速度(VS),舒张早期峰值速度(VE)、舒张晚期峰值速度(VA)。结果左束支传导阻滞患者ICT、IRT较正常对照组明显延长(P<0.01),ET缩短(P<0.05);SMPI、DMPI、MPI较对照组明显增高(P<0.01);同一室壁运动虽然存在一定梯度,但VS、VE明显减低。结论LBBB时,左心室内电机械活动不同步,收缩协同失调,引起局部心肌收缩舒张功能减低。     

多普勒超声检测心肌运动指数评价扩张型心肌病左心功能

目的 :探讨超声检测心肌运动指数对评价扩张型心肌病 (DCM )左心功能的临床价值。方法 :DCM患者 31例 ,正常对照者 6 2例 ,应用多普勒超声心动图记录二尖瓣舒张期和左心室流出道收缩期脉冲多普勒血流频谱 ,测量心肌运动指数。结果 :①与正常对照组相比 ,DCM组等容舒张期时间 [(98.39± 2 0 .83)ms∶(6 6 .4 5±11.32 )ms ,P <0 .0 1]及等容收缩期时间 [(39.5 2± 13.31)ms∶(2 1.4 5± 7.6 5 )ms,P <0 .0 1]明显延长、射血时间[(2 2 3.39± 4 0 .93)ms∶(2 73.0 6± 2 1.0 1)ms ,P <0 .0 1]明显缩短 ,导致心肌运动指数 (0 .6 3± 0 .14∶0 .32± 0 .0 4 ,P <0 .0 1)明显升高 ,相关分析表明 ,心肌运动指数与左心功能障碍程度呈正相关 ;②相关分析显示 ,心肌运动指数与年龄、心率、血压无相关性。结论 :①心肌运动指数是评价DCM患者左心功能简便而准确的多普勒超声新指标 ,且与左心功能障碍程度呈正相关 ;②心肌运动指数不受年龄、心率、血压的影响     

Tei指数在心血管疾病中的应用

Tei指数又称心肌做功指数,最初由日本学者Tei于1995年提出,用于临床综合评价心脏整体收缩和舒张功能[1].该指数测量简便易行,与其他常用评价心脏功能的指标如左室射血分数(LVEF)、舒张早期和舒张晚期血流峰值比值(E/A值)等相比,其不受血压、心律、心脏几何形态、瓣膜反流及超声条件等的影响,重复性好,敏感性高.现将Tei指数在心血管疾病中的应用进展作一综述. 1 Tei指数的概念及原理 Tei指数为心室等容收缩时间(ICT)与等容舒张时间(IRT)之和与心室射血时间(ET)的比,即Tei指数=(ICT+ IRT)/ET.常用脉冲多普勒测量,成人左心室Tei指数正常值为0.38 ±0.05,右室为0.28 ±0.04.心脏发挥正常的收缩、舒张功能依赖于心腔内压力的变化,等容收缩期及等容舒张期内左心室压力变化速率(dp/dt)是反映左心室收缩及舒展弛缓的指标之一[2].     

利用组织多普勒评价左束支阻滞患者心室内不同步

利用组织多普勒测量不同步指数评价左束支阻滞 (LBBB)患者心室内不同步 ,对 15例LBBB患者 (LBBB组 )和 15例正常人 (对照组 )左心室各壁基底、中间、心尖段 ,获取组织多普勒速度曲线 ,分别测量QRS波起点到S波起点的时间 (Q Sb) ,计算心室内同步性指数 (TSI)和各室壁壁内的同步性指数 (RSI)。结果 :LBBB组患者各壁Q Sb延长 ,以室间隔、前壁、下后壁显著 ;TSI和左室室间隔的RSI较对照组明显增高 (分别为 30 .86± 9.78msvs 14 .81± 6 .89ms;2 7.13± 16 .82msvs 12 .19± 10 .70ms ,P均 <0 .0 1)。结论 :LBBB时左室激动顺序异常 ,左室各壁各节段出现不同程度的收缩延迟 ,心室内不同步明显 ;同一室壁内的不同步 ,以室间隔最显著。     

Tei指数评价风湿性心脏病二尖瓣狭窄患者左心室功能

目的运用脉冲型组织多普勒技术(PW-TDI)测算左心室心肌综合指数(Tei指数),评价风湿性心脏病二尖瓣狭窄(MS)患者左心室功能,并探讨其与右心室功能的关系。方法测量30例MS患者及25例健康对照者的常规超声心动图指标,在PW-TDI条件下测算左心室二尖瓣环四个位点(后间隔、侧壁、前壁、下壁)的Tei值及其均值(t-Tei)以及三尖瓣环位点(右心室游离壁)的Tei值,对各组值进行对比分析。结果(1)与正常对照组相比,MS患者左、右心室的Tei值明显增大(P<0.001);左心室二尖瓣环四个位点t、-Tei、右心室三尖瓣环位点的等容舒张时间延长(P<0.001)、射血时间缩短(P<0.01或P<0.05),前壁、下壁及t-Tei等容收缩时间延长(P<0.05);(2)相关性分析表明MS患者左、右心室的Tei指数呈正相关关系(r=0.73,P<0.001)。结论MS患者左心室在收缩功能正常时舒张功能已减退,左、右心室功能状态可能相互影响,重视改善MS患者左心室功能具有重要的临床意义。     

心肌致密化不全患者心肌收缩运动同步性研究

目的 利用定量组织速度成像(quantitative tissue velocity imganig,QTVI)技术分析探讨心肌致密化不全患者的心肌收缩同步性运动情况.方法 采集18例心肌致密化不全患者(NVM组)和30例健康对照组的常规二维图像,启动组织多普勒(DTI)程序,获取标准心尖位左心室长轴观、两腔观和四腔观共3个切面的QTVI图像.分别描绘左心室侧壁、后间隔、前壁、下壁、前间隔和后壁等6个室壁的基底段及中间段共12个节段的组织速度曲线.测量左心室12个节段的QRS波起始点至各节段收缩期达峰时间(Q-Ts),计算48例检查者左心室12个节段的Ts最大差值(Max-△Ts).结果 NVM组和健康对照组相比,左心室各壁基底段Q-Ts均明显长(P均<0.001),且以左心室侧壁、后壁、下壁延迟为重;左心室各壁中间段Q-Ts均明显长(P均<0.001),且以左心室下壁、侧壁、后壁延迟为重.NVM组左心室12个节段的Max-△Ts为(161.9±93.2)ms,显著大于正常对照组的(61.2±27.4)ms,P<0.001.结论 左心室心肌致密化不全患者存在心肌收缩运动的不同步性.且左心室各壁中间段Q-Ts最延迟的部位依次为下壁、侧壁、后壁,有别于既往文献报道的其他原因所致心力衰竭时左心室各壁中间段Q-Ts最延迟的部位依次为侧壁、后壁、下壁.     

应变成像定量评价冠心病病人局部心肌收缩功能

目的 应用应变成像技术定量评价冠心病局部心肌收缩能.方法 应用应变成像对冠心病病人53例和正常人42名左心室前间隔与后壁径向、各室壁节段纵向收缩期峰值应变进行测定,并以冠状动脉造影结果为标准进行对比分析.结果 冠心病病人缺血心肌的收缩期峰值应变表现为明显减低、消失,甚至倒置.冠心病组各室壁缺血节段收缩期径向、纵向峰值应变测值均较对照组相应节段明显减低.结论 冠心病缺血心肌收缩期峰值应变明显减低,应变成像技术是临床无创、定量评价冠心病局部心肌功能的新方法.     

多普勒组织成像对糖尿病患者早期左心室功能异常的评估价值研究

目的分析多普勒组织成像(DTI)对糖尿病(DM)患者早期左心室功能异常的评估价值。方法选取2013年6月—2014年6月在江苏省如皋市人民医院超声科进行检查的DM患者40例作为研究组,同期体检健康者35例作为对照组。两组患者均采用常规超声检查检测左心室舒张早、晚期最大血流速度(E值、A值);采用改良Simpson法检测左心室射血分数(LVEF)、左心室收缩末期容积(LESV)、左心室舒张末期容积(LEDV);采用DTI检查检测瓣环左心室收缩期峰值速度(Sa)、局部等容收缩时间(ICT)、局部射血时间(ET)及左心室舒张早、晚期运动峰值(Em、Am)。结果两组患者LESV、LEDV、LVEF比较,差异均无统计学意义(P>0.05);研究组患者E值低于对照组、A值高于对照组(P<0.05)。两组患者前壁、后壁、侧壁、后室间隔Sa及各部位ICT比较,差异均无统计学意义(P>0.05);研究组患者下壁和前室间隔Sa均低于对照组,各部位ET均高于对照组(P<0.05);研究组患者Em低于对照组,Am高于对照组(P<0.05)。结论 DTI能够较敏感、可靠地检测出DM患者早期心肌运动异常,可作为评价DM患者早期左心室舒张、收缩功能异常的检查手段。     

多普勒组织成像评价正常人心肌舒缩运动速度

目的　探讨心肌舒缩运动变化的相关因素。方法　标准切面 (左心室长轴、短轴 )用脉冲多普勒组织成像(DTI)测定室间隔、前壁、下后壁的内膜下心肌及外膜下心肌运动峰值速度。结果　各个室壁及各层心肌收缩期 s峰值速度不相同。内膜下心肌的 s峰值速度大于外膜下心肌的 s峰值速度 ,室间隔左心室面 s峰值速度大于右心室面 s峰值速度 ,两者间存在速度阶差。长轴左心室后壁 s峰值速度大于室间隔 s峰值速度 ,短轴后壁 s峰值速度大于前壁 s峰值速度。 s峰值速度与年龄无相关 ,舒张期 a峰值速度与年龄呈中度相关 ,e/ a比与年龄呈中度负相关 ,室壁运动的 e/ a比与二尖瓣血流 E/ A比呈中度相关。结论　脉冲 DTI可用于评价心肌的舒缩功能     

The effect of isolated left bundle branch block on the myocardial velocities and myocardial performance index

OBJECTIVES: This study was planned in order to investigate the effect of left bundle branch block (LBBB) on myocardial velocities obtained by tissue Doppler echocardiography (TDE) and myocardial performance index (MPI). METHODS: Subjects with LBBB (n = 61) and age-matched healthy subjects (n = 60) were enrolled in the study. Left ventricular (LV) ejection fraction (EF), mitral inflow velocities (E-wave and A-wave), isovolumetric contraction and relaxation time (ICT and IRT), ejection time (ET), and flow propagation velocity (Vp) were measured by conventional echocardiography. Systolic velocity (Sm), early and late diastolic velocities (Em and Am) and time intervals were measured by TDE. MPI was calculated by the formula (ICT + IRT)/ET. RESULTS: LVEF and mitral E/A ratio were similar in both groups. Vp was lower in the LBBB group than in the control group, whereas the E/Em and the E/Vp ratio was higher. LV Sm and Em/Am ratio were lower in LBBB group. Right ventricular Sm and Em/Am ratio were similar in both groups. LV mean and RV MPI were significantly increased in LBBB group. CONCLUSION: These findings obtained by TDE show that isolated LBBB impairs the ventricular functions. Both of the LV and RV dysfunctions shown by the new parameters may contribute to increased morbidity and mortality in cases with isolated LBBB.     

Is the myocardial performance index a reliable parameter in patients with restrictive filling pattern?

OBJECTIVE: The myocardial performance index (MPI) enables noninvasive estimation of combined systolic and diastolic function. The only diastolic function parameter used in the index is the isovolumic relaxation time (IRT). We assessed the impact of shortened IRT in restrictive filling pattern on MPI. METHODS: The MPI was defined as the sum of the isovolumic contraction time (ICT) and the IRT divided by the ejection time (ET), and was calculated in 13 controls (group 1), and 39 patients with ischemic heart disease with left ventricular systolic dysfunction (ejection fraction<50%). The patients were classified into two groups according to mitral early filling deceleration time (DT): group 2 with DT>140 ms (n = 20), and group 3 with DT < or =140 ms (n = 19). RESULTS: The ICT was longer and the ET was shorter in group 2 and group 3 than in group 1. The ICT and ET were not different in group 2 and group 3. The IRT was longer in group 2 (130+/-23 ms) compared to group 1 (82+/-10 ms, p<0.001) and group 3 (85+/-19 ms, p<0.001), but did not differ between group 1 and group 3. The MPI was higher in group 2 and group 3 compared to group 1 (0.79+/-0.25 and 0.65+/-0.19 vs 0.42+/-0.08, p<0.001 and p<0.001; respectively). However, it was lower in group 3 than in group 2 (p=0.03) due to significantly shortened IRT. CONCLUSION: Shortened IRT in patients with restrictive filling pattern results in reduction of the MPI. Therefore, the MPI may not reflect true level of ventricular dysfunction in these patients.     

Functional abnormalities in isolated left bundle branch block. The effect of interventricular asynchrony

Eighteen patients with isolated left bundle branch block (LBBB) were compared with 10 normal control subjects. Apexcardiograms, phonocardiograms, electrocardiograms, two-dimensional and dual M-mode echocardiograms, and radionuclide ventriculograms (RNV) were performed. There were no differences in the timing of right ventricular events between LBBB and normal subjects; however, striking delays in left ventricular systolic and diastolic events were apparent in the LBBB group. The delay was associated with shortening of left ventricular diastole and resultant increase in the ratio of right to left ventricular diastolic time in LBBB (1.2 +/- 0.08) compared with normal (1.0 +/- 0.06), p less than 0.0001. First heart sound (S1) amplitude, expressed as the ratio S1/S2, was decreased in LBBB compared with normal (0.67 +/- 0.2 compared with 1.34 +/- 0.25, p less than 0.01), in part due to wide separation of the valvular contributors to S1. The abnormal interventricular septal motion in LBBB corresponded to periods of asynchrony in contraction, ejection, end systole, and end diastole between right and left ventricles. Radionuclide ventriculograms revealed decreased regional ejection fraction of the septum in LBBB (40 +/- 16%) compared with 67 +/- 7% in normal subjects (p less than 0.001), while the apical and lateral regional ejection fractions were similar in the two groups. This loss of septal contribution resulted in a reduction in global ejection fraction in LBBB compared to normals (54 +/- 7% compared with 62 +/- 5%, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)     

Left Bundle Branch Block,an Old–New Entity

Left bundle branch block (LBBB) is generally associated with a poorer prognosis in comparison to normal intraventricular conduction, but also in comparison to right bundle branch block which is generally considered to be benign in the absence of an underlying cardiac disorder like congenital heart disease. LBBB may be the first manifestation of a more diffuse myocardial disease. The typical surface ECG feature of LBBB is a prolongation of QRS above 0.11 s in combination with a delay of the intrinsic deflection in leads V5 and V6 of more than 60 ms and no septal q waves in leads I, V5, and V6 due to the abnormal septal activation from right to left. LBBB may induce abnormalities in left ventricular performance due to abnormal asynchronous contraction patterns which can be compensated by biventricular pacing (resynchronization therapy). Asynchronous electrical activation of the ventricles causes regional differences in workload which may lead to asymmetric hypertrophy and left ventricular dilatation, especially due to increased wall mass in late-activated regions, which may aggravate preexisting left ventricular pumping performance or even induce it. Of special interest are patients with LBBB and normal left ventricular dimensions and normal ejection fraction at rest but who may present with an abnormal increase in pulmonary artery pressure during exercise, production of lactate during high-rate pacing, signs of ischemia on myocardial scintigrams (but no coronary artery narrowing), and abnormal ultrastructural findings on myocardial biopsy. For this entity, the term latent cardiomyopathy had been suggested previously.     

Effect of intermittent left bundle branch block on left ventricular performance

In a patient with intermittent left bundle branch block (LBBB), left ventricular (LV) performance was compared during normal and delayed left ventricular activation. LBBB was associated with delay in onset of left ventricular systole by 0.02 second, prolongation of isovolumic contraction time by 0.038 second, fall in mean systemic arterial blood pressure by 27 mm Hg, and marked reduction in the rate of left ventricular isovolumic pressure rise (dp/dt) at the peak common isovolumic pressure. LBBB depressed left ventricular performance, probably by causing a less synchronous ventricular contraction.     

Importance of left ventricular activation in determining myocardial performance (Tei) index: comparison with total isovolumic time

BACKGROUND: The Tei index is commonly used as a measure of "combined systolic and diastolic function". A sensitive and specific index of intrinsic myocardial contraction and relaxation would be independent of abnormal activation. We aimed to determine whether the Tei index fulfils this criterion in patients with normal activation or left bundle branch block (LBBB), normal or dilated left ventricular (LV) cavities, with or without coronary artery disease (CAD). METHODS: We studied 32 controls and 124 patients; 49 had CAD and normal LV size (11 LBBB), 27 had non-ischaemic dilated cardiomyopathy (DCM, 11 LBBB), and 48 had ischaemic DCM (17 LBBB). Tei index (isovolumic contraction time+isovolumic relaxation time/ejection time) and total isovolumic time (t-IVT: [60-(total ejection time+total filling time]) were measured using Doppler echocardiography. RESULTS: Tei index and t-IVT were prolonged in LBBB (by 0.6 and 9.1 s/min, P<0.001). T-IVT identified LBBB with greater predictive accuracy than Tei index (sensitivity 97% vs. 90%, specificity 93% vs. 91%, P<0.05). Tei index and t-IVT were also prolonged in DCM (by 0.2 and 3.1 s/min, both P<0.001). Although Tei index identified DCM with sensitivity 71%, this fell to 53% when LBBB was excluded (P<0.05). CAD had no effect on Tei index or t-IVT. CONCLUSIONS: The Tei index is not a measure of intrinsic myocardial systolic and diastolic function, since its main determinant is ventricular activation rather than cavity size. T-IVT, however, is more sensitive to activation, is unrelated to cavity size or CAD, and may thus be a more accurate measure of the mechanical consequences of ventricular activation in a variety of cardiac conditions.     

Echocardiography of ventricular septal movement in left bundle branch block with left ventricular diastolic overload.

Four patients with left bundle branch block (LBBB) and left ventricular volume overload had sustained posterior ventricular septal systolic motion with no early septal posterior systolic motion. There was earlier than normal peak posterior septal systolic motion and earlier than normal anterior systolic septal motion. It is suggested that volume overload of the left ventricle alters ventricular septal motion in left bundle branch block.