Assessment of Interventricular Dyssynchrony by Real Time Three‐Dimensional Echocardiography: An In Vitro Study in a Porcine Model

Background: Loss of synchronous contraction between or within the right and left ventricle (RV, LV) leads to adverse ventricular function. We used real time three‐dimensional echocardiography (RT3DE) for evaluation of severity of interventricular dyssynchrony and function in a porcine heart model. Methods: Six fresh in vitro porcine hearts were used to create a controlled model of LV and RV dyssynchrony using two sets of pulsatile pumps. Synchronized and dyssynchronized pump settings were used with two different dyssynchronized settings: LV filled first and RV filled first. Results: There was good correlation between actual measurement and RT3DE for interventricular time difference (r = 0.95, P < 0.0001) and stroke volume (SV) for LV and RV (0.89, 0.85; P < 0.0001, respectively). RT3DE data showed a small but significant underestimation for actual volume (P < 0.05). The intra‐ and interobserver variabilities are 2.9 ± 1.5% and 3.1 ± 5.4% for LV and RV SVs, and 1.7 ± 2.4% and 2.2 ± 3.2% for time differences by RT3DE. There was significant difference in RV SV between synchrony and dyssynchrony when the RV filled first (P < 0.05), but not in other groups. The same pattern was found in RT3DE derived SVs (synchrony versus dyssynchrony with RV filled first, P < 0.05). Conclusions: There is no compromise in LV SV during interventricular dyssynchrony; but RV SV was significantly diminished when the RV filled first. RT3DE is a feasible, robust and reproducible method to identify interventricular dyssynchrony and to evaluate ventricular SVs. (Echocardiography 2010;27:709‐715)     

Three-Dimensional Echocardiographic Reconstruction of the Left Ventricle by a Transesophageal Tomographic Technique

Accurate determination of left ventricular (LV) volume has important therapeutic and prognostic implications in patients with cardiac disease. Volume estimations by two-dimensional techniques are not very accurate due to geometric assumptions. Objectives: To validate LV volume determinations by a new transesophageal three-dimensional echocardiographic technique. We performed three-dimensional reconstruction of the LV using an echo-computed tomographic (CT) technique based on serial pullback parallel slice imaging technique in both in vitro and in vivo settings. Fourteen latex-balloons with various sizes (30–235 mL) and shapes (conical, pear shaped, round, elliptical, and aneurysms in various locations) filled with known volumes of water were imaged in a water bath. From the static three-dimensional image, the LV long axis was defined and the LV was sectioned perpendicular to this axis into 2-mm slices. The volume of each slice was calculated with the observer blinded to the actual volume as the product of the slice thickness and the manually traced perimeter of the slice and the LV volume as the sum of the volumes of the slices (Simpson's method). The calculated LV volume closely correlated with the actual volume (r = 0.99, P < 0.0001, calculated volume = 1.06x – 11.3, Δvolume =-5.7 ± 10.0 cc). Using the same system, transesophageal echocardiographic (TEE) images of the LV were obtained in 15 patients gated to respiration and ECG. Satisfactory dynamic three-dimensional reconstruction of the LV was possible in ten patients. The three-dimensional LV volumes (systolic and diastolic) using Simpson's method correlated well with those obtained from biplane or multiplane TEE images using the area length method (r = 0.89, P < 0.0001, y = 12.7 + 0.84x, Δvolume = 1.3 ± 18.1 cc). The LV major-axis diameters by the two methods showed very close correlations as well (r = 0.86, P < 0.0001, y = 19 + 0.74x, Δdiameter = 1.0 ± 7.2 mm). We conclude that three-dimensional LV volume calculation by the echo-CT technique is intrinsically sound, is independent of LV geometry, and with some limitations, is applicable in vivo.     

Tobacco smoke-induced left ventricular remodelling is not associated with metalloproteinase-2 or -9 activation

AIM: To investigate the role of MMP-2 and MMP-9 in cardiac remodelling induced by tobacco smoke exposure in rats. METHODS: Rats were allocated into two groups: C (n=9): control animals; ETS (n=9): exposed to tobacco smoke. After 4months, the animals underwent echocardiography, morphometric study and determination of MMP-2 and MMP-9 activity. RESULTS: ETS rats had larger diastolic (C=15.6 +/-1.2 mm/kg, ETS=18.0+/-0.9 mm/kg; p < 0.001) and systolic (C=7.3+/-1.2 mm/kg, ETS=9.2+/-0.9 mm/kg; p=0.001) ventricular diameters adjusted for body weight. Fractional shortening (C=53+/-4.8%, ETS=48+/- 3.3%; p=0.031) and ejection fraction (C=0.89+/-0.03, ETS=0.86+/-0.02; p=0.030) were smaller in the ETS group. Myocyte cross-sectional area (C=245+/-8 microm2, ETS=253+/-8 microm2; p=0.028) was higher in ETS rats. There were no differences in MMP-2 (C=50+/-14%; ETS=43+/-11%, p=0.228) or MMP-9 (C=0.36+/-0.3%; ETS=0.62+/-0.3%, p=0.630) activity between the groups. CONCLUSION: MMP-2 and MMP-9 did not participate in the remodelling process induced by tobacco smoke exposure.     

Newer doppler measures of left ventricular diastolic function

Left ventricular (LV) diastolic dysfunction is an important cause of heart failure, and recent advances in the application of Doppler techniques allow a semiquantitative assessment of LV diastolic performance. This review discusses the use of Doppler echocardiography in the comprehensive assessment of LV diastolic function and performance in terms of the normal mitral and pulmonary venous flow profiles, their physiologic basis, and alteration in diseased states. There is also a discussion on the newer aspects of mitral flows such as relative durations of mitral A and pulmonary vein AR waves, E- and A-wave propagation inside the LV with their hemodynamic correlates, and derivation of ventricular dP/dt and Tau from the mitral regurgitation velocity profile. Analysis of these flow profiles and the other Doppler measures alluded to above allow one to make a fairly precise hemodynamic assessment of a patient in terms of left atrial pressure, LV relaxation and stiffness and the profile of LV diastolic pressure in terms of pre-‘a’ wave and ‘a’ wave pressures and ventricular end-diastolic pressure.     

The Effects of Simvastatin on Left Ventricular Hypertrophy and Left Ventricular Function in Patients with Essential Hypertension

This study is to evaluate the effects of Simvastatin on left ventricular hypertrophy and left ventricular function in patients with essential hypertension. Untreated or noncompliance with drug treatment patients with simple essential hypertension were treated with a therapy on the basis of using Telmisartan to decrease blood pressure (BP). There were 237 patients who had essential hypertension combined with left ventricular hypertrophy as diagnosed by echocardiography, taken after their BPs were decreased to meet the values of the standard normal. Among them, there were only 41 out of the original 237 patients, 17.3%, who had simple essential hypertension combined with left ventricular hypertrophy without any other co-existing disease. They were the patients selected for this study. All patients were randomly, indiscriminately divided into two groups: one was the control group (Group T), treated with the Telmisartan-based monotherapy; the other was the target group (Group TS), treated with the Telmisartan-based plus simvastatin therapy. The changes of left ventricular hypertrophy and left ventricular function were rediagnosed by echocardiography after 1 year. The results we obtained from this study were as follows: (i) The average BPs at the beginning of the study, of simple essential hypertension combined with left ventricular hypertrophy, were high levels (systolic blood pressure (SBP) 189.21 ± 19.91 mm Hg, diastolic blood pressure 101.40 ± 16.92 mm Hg). (ii) The Telmisartan-based plus simvastatin therapy was significantly effective in lowering the SBP (128.26 ± 9.33 mm Hg vs. 139.22 ± 16.34 mm Hg). (iii) After the 1-year treatment, the parameters of left ventricular hypertrophy in both groups were improved. Compared to group T, there were no differences in the characteristics of the subjects, including interventricular septum, left ventricular mass, left ventricular mass index, ejection fraction, left atrium inner diameter at baseline. The patients’ interventricular septum (Group TS 10.30 ± 1.80 mm vs. Group T 10.99 ± 1.68 mm, P < .05), LVM (Group TS 177.43 ± 65.40 g vs. Group T 181.28 ± 65.09 g, P < .05), and LVMI (Group TS 100.97 ± 37.33 g/m² vs. Group T 106.54 ± 27.95 g/m², P < .05), all dropped more prominently (P < .05) in group TS; the ejection fraction rose more remarkably in group TS (Group TS: 57.50 ± 16.41% to 65.43 ± 11.60%, P < .01 while showing no change in Group T); the left ventricular hypertrophy reversed more significantly and the left ventricular systolic function improved more. (iv) The left atrium inner diameter of Group TS decreased (P < .01), the ratio of E/A, which indicates the left ventricular diastolic function, continued to drop further, showing no change to the trend of left ventricular diastolic function declination. Patients who have hypertension with left ventricular hypertrophy usually suffer other accompanying diseases at the same time. Telmisartan-based plus Simvastatin treatment can significantly reduce SBP, reverse left ventricular hypertrophy, improve the left ventricular systolic function, but it has no effect on reversing the left ventricular diastolic function. This experiment indicated that Simvastatin can reverse left ventricular hypertrophy and improve left systolic function.     

Positional localization: three-dimensional transthoracic echocardiographic techniques for the measurement of cardiac mass, volume, and function

An accurate and reproducible determination of cardiac volume and mass is important for the selection and timing of therapeutic interventions. Quantitative three-dimensional echocardiography has evolved to provide these measurements with the use of a noninvasive, readily available, and inexpensive technique. We introduce and review the principle of positional localization as well as the clinical application of this technique for the measurement of cardiac volume and mass.     

老年高血压病患者血浆内皮素与左室重量和功能关系的研究

目的探讨老年高血压病患者(EH)血浆内皮素(ET)与左室重量和功能的关系。方法采用放射免疫分析法和多昔勒超声心动图技术检测86例EH患者和57例健康对照者血浆ET的浓度及室间隔(IVST)、左室后壁厚度(PWT)、左室心肌重量指数(LVMI)以及左室流入道E峰和A峰比值(E/A)、E峰加速面积(EAA)。结果EH组ET、IVST、PWT、LVMI显著高于对照组(P值均＜0．01),E/A、EAA显著低于对照组(P＜0．01);EH组ET与IVST、LPWT、LVMI之间均存在着显著正相关(P值均＜0．01),ET与E/A、EAA之间均存在着显著负相关(P值均＜0．01)。结论ET可能是引起EH患者左室肥厚及舒张功能不全的原因之一。     

老年高血压病患者血浆内皮素与左室重量和功能关系的研究

目的探讨老年高血压病患者（ＥＨ）血浆内皮素（ＥＴ）与左室重量和功能的关系。方法采用放射免疫分析法和多普勒超声心动图技术检测８６例ＥＨ患者和５７例健康对照者血浆ＥＴ的浓度及室间隔（ＩＶＳＴ）、左室后壁厚度（ＰＷＴ）、左室心肌重量指数（ＬＶＭＩ）以及左室流入道Ｅ峰和Ａ峰比值（Ｅ／Ａ）、Ｅ峰加速面积（ＥＡＡ）。结果ＥＨ组ＥＴ、ＩＶＳＴ、ＰＷＴ、ＬＶＭＩ显著高于对照组（Ｐ值均＜０．０１）,Ｅ／Ａ、ＥＡＡ显著低于对照组（Ｐ＜０．０１）;ＥＨ组ＥＴ与ＩＶＳＴ、ＬＰＷＴ、ＬＶＭＩ之间均存在着显著正相关（Ｐ值均＜０．０１）,ＥＴ与Ｅ／Ａ、ＥＡＡ之间均存在着显著负相关（Ｐ值均＜０．０１）。结论ＥＴ可能是引起ＥＨ患者左室肥厚及舒张功能不全的原因之一。     

Real-time volumetric echocardiography: the technology and the possibilities

The heart is a dynamic organ with complexities in its shape. As such, it places special demands on three-dimensional techniques for reconstruction. Real-time volumetric echocardiography, which is based on phased array and parallel processing principles to enhance line density within a scan volume, provides rapid image acquisition. We introduce the principle, potential clinical importance, current limitations, and future of volumetric imaging methods.     

Quantitation of ventricular size and function: principles and accuracy of transthoracic rotational scanning

Two-dimensional echocardiography is a readily applicable method for the quantification of ventricular volumes. However, it is limited by assumptions regarding ventricular shape. Three-dimensional echocardiography has emerged as a more accurate and reproducible approach to ventricular volume and functional assessment compared with two-dimensional echocardiography. We review the principles of transthoracic rotational scanning and its clinical application for quantitative assessment of ventricular volume and function.     

Determination of left ventricular volume, ejection fraction, and myocardial mass by real-time three-dimensional echocardiography

Reconstructed three-dimensional (3-D) echocardiography is an accurate and reproducible method of assessing left ventricular (LV) functions. However, it has limitations for clinical study due to the requirement of complex computer and echocardiographic analysis systems, electrocardiographic/respiratory gating, and prolonged imaging times. Real-time 3-D echocardiography has a major advantage of conveniently visualizing the entire cardiac anatomy in three dimensions and of potentially accurately quantifying LV volumes, ejection fractions, and myocardial mass in patients even in the presence of an LV aneurysm. Although the image quality of the current real-time 3-D echocardiographic methods is not optimal, its widespread clinical application is possible because of the convenient and fast image acquisition. We review real-time 3-D echocardiographic image acquisition and quantitative analysis for the evaluation of LV function and LV mass.     

The assessment of left ventricular filling dynamics using an online automatic border detection algorithm: comparison with cineventriculography

An echocardiographic system has been developed that performs automatic endocardial border detection and instantaneously calculates and displays a waveform of left ventricular cavity area versus time. The purpose of this study was to compare measurements of left ventricular filling dynamics from automatic border detection echocardiography with similar measurements from cineventriculography. Thirty-three patients undergoing cardiac catheterization had automatic border detection echocardiography performed within 45 minutes of cineventriculography. Ten patients had normal catheterization findings and 23 had cardiac disease. The automatic border detection waveforms generated from two echocardiographic views were measured to determine the fraction of filling occurring during the early diastolic rapid filling phase and during the filling phase resulting from atrial contraction. Similar fractions were derived from curves generated from frame-by-frame measurements of cineangiographic volumes. Results were analyzed by correlating echocardiographic and cineventriculographic results, and by a limits of agreement analysis (limits of agreement were +/- 2 standard deviations of the mean difference between echocardiography and cineventriculography). There were significant correlations between echocardiography and cineventriculography for each of the parameters studied. The best results were obtained for the apical four-chamber view (rapid filling fraction r = 0.72, P < 0.0001, atrial filling fraction r = 0.56, P < 0.001). Differences in filling patterns between normal and abnormal patient groups detected by cineventriculography were also detected by automatic border detection echocardiography. However, broad limits of agreement were observed, that may limit the ability of the automatic border detection system to reliably predict cineventriculographic results in an individual patient. Automatic border detection echocardiography can provide information about left ventricular filling dynamics that is similar to that obtained from frame-by-frame analysis of cineventriculograms. However, the variability in the results may limit the application of the technique in individual patients.     

右心功能评价技术研究进展

随着人们对心脏功能的深入研究,右心室在循环系统中的作用日益受到重视。各种评价右心室功能的检测技术———脉冲多普勒超声心动图、二维超声心动图、三维超声心动图、声学定量技术、X线心室造影、放射性核素心室造影、电子束计算机体层成像、磁共振成像在评价右心功能方面所显示出的优势,使人们对右心室在循环系统中的作用有了进一步的了解,充分利用各种检测技术评价右心室功能。     

Mitral annulus motion versus long-axis fractional shortening

BACKGROUND: In most echocardiographic studies concerning mitral annulus motion (MAM) in the assessment of left ventricular (LV) systolic function, comparisons have been performed between MAM, which represents a distance, and ejection fraction (EF), which represents a ratio between volumes. However, in theory, it is probably more suitable to compare the long-axis fractional shortening (FS(L)) (the ratio between the change in length [ie, MAM] and the end-diastolic length of the left ventricle) with EF. OBJECTIVES: To compare EF with MAM and EF with FS(L) in the assessment of LV systolic function. METHODS: Thirty healthy subjects were investigated using echo-cardiography, and the linear correlations between EF and MAM, and EF and FS(L) were calculated. RESULTS: The linear correlation (r) was found to be higher between EF and FS(L) (r=0.65; P<0.001) than between EF and MAM (r=0.49; P<0.01). CONCLUSIONS: The higher correlation between EF and FS(L) than between EF and MAM suggests that FS(L), which includes a correction for ventricular length, may be a more suitable index of LV systolic function than MAM per se.     

维持性血液透析对尿毒症患者左心室收缩和舒张功能的影响及其相关因素分析

目的应用多普勒超声心动图检测维持性血液透析患者左心室收缩及舒张功能指标,并探讨相关因素对心脏功能的影响。方法根据血压、血红蛋白、每周透析时间和KT/V值将44例尿毒症患者分为透析充分组(A组,24例)和未充分透析组(B组,17例)。血液透析前后及首次超声心动检查一年后透析前测定左房内径(LAD)、左室舒张末内径(LVDd)、左室收缩末内径(LVDs)、室间隔厚度(IVST)、左室后壁厚度(LVPWT),得出左室射血分数(EF)、左室短轴缩短率(FS),测定心率(HR)。并依据上述指标判断左心室收缩及舒张功能。结果首次超声心动检查左心室舒张功能减退占59.1%,收缩功能减退占18.2%;左心室肥厚占43.2%。LAD、LVDd、LVDs、IVST、LVPWT值较对照组明显增加,FS、EF、E/A、EI/AI较对照组明显降低,单次透析前后FS、EF、E/A、EI/AI无显著变化。一年后左心室舒张功能减退占80.5%;收缩功能减退占22.0%,均同时伴有舒张功能减退。左心室肥厚占70.7%。LAD、LVDd、LVDs、IVST、LVPWT值明显增加,FS、EF、E/A、EI/AI明显降低;A、B组LAD、LVDd、LVDs、IVST、LVPWT均较对照组明显增加,B组尤为显著;B组E/A、EI/AI较A组明显下降。结论长期维持性血液透析患者首先出现左心室舒张功能障碍,进而影响收缩功能;单次血液透析后左心室收缩及舒张功能无改善;血液透析一年后左心室收缩、舒张功能明显降低,尤以舒张功能降低显著。未充分透析患者舒张功能下降更明显。