Reproducibility and accuracy of echocardiographic measurements of left ventricular parameters using real-time three-dimensional echocardiography

OBJECTIVES: We sought to determine whether assessment of left ventricular (LV) function with real-time (RT) three-dimensional echocardiography (3DE) could reduce the variation of sequential LV measurements and provide greater accuracy than two-dimensional echocardiography (2DE). BACKGROUND: Real-time 3DE has become feasible as a standard clinical tool, but its accuracy for LV assessment has not been validated. METHODS: Unselected patients (n = 50; 41 men; age, 64 +/- 8 years) presenting for evaluation of LV function were studied with 2DE and RT-3DE. Test-retest variation was performed by a complete restudy by a separate sonographer within 1 h without alteration of hemodynamics or therapy. Magnetic resonance imaging (MRI) images were obtained during a breath-hold, and measurements were made off-line. RESULTS: The test-retest variation showed similar measurements for volumes but wider scatter of LV mass measurements with M-mode and 2DE than 3DE. The average MRI end-diastolic volume was 172 +/- 53 ml; LV volumes were underestimated by 2DE (mean difference, -54 +/- 33; p < 0.01) but only slightly by RT-3DE (-4 +/- 29; p = 0.31). Similarly, end-systolic volume by MRI (91 +/- 53 ml) was underestimated by 2DE (mean difference, -28 +/- 28; p < 0.01) and by RT-3DE (mean difference, -3 +/- 18; p = 0.23). Ejection fraction by MRI was similar by 2DE (p = 0.76) and RT-3DE (p = 0.74). Left ventricular mass (183 +/- 50 g) was overestimated by M-mode (mean difference, 68 +/- 86 g; p < 0.01) and 2DE (16 +/- 57; p = 0.04) but not RT-3DE (0 +/- 38 g; p = 0.94). There was good inter- and intra-observer correlation between RT-3DE by two sonographers for volumes, ejection fraction, and mass. CONCLUSIONS: Real-time 3DE is a feasible approach to reduce test-retest variation of LV volume, ejection fraction, and mass measurements in follow-up LV assessment in daily practice.     

Comparison of two- and three-dimensional echocardiography with sequential magnetic resonance imaging for evaluating left ventricular volume and ejection fraction over time in patients with healed myocardial infarction

Echocardiographic follow-up of left ventricular (LV) volumes is difficult because of the test-retest variation of 2-dimensional echocardiography (2DE). We investigated whether the accuracy and reproducibility of real-time 3-dimensional echocardiography (RT3DE) would make this modality more feasible for serial follow-up of LV measurements. We performed 2DE and RT3DE and cardiac magnetic resonance imaging (MRI) in 50 patients with previous infarction and varying degrees of LV function (44 men; 61 +/- 11 years of age) at baseline and after 1-year follow-up. Images were obtained during breath-hold and measurements of LV volumes and ejection fraction were made offline. Over follow-up, end-diastolic volume decreased from 192 +/- 53 to 187 +/- 60 ml (p <0.01), end-systolic volume decreased from 104 +/- 51 to 95 +/- 53 ml (p <0.01), and ejection fraction increased from 48 +/- 12% to 51 +/- 12% (p <0.01). MRI showed that LV mass shrank from 183 +/- 39 to 182 +/- 37 g (p <0.01). The correlation between change in RT3DE and change in MRI was greater than the correlations of 2DE with MRI for measurement of end-diastolic volume (r = 0.47 vs 0.02, p <0.01), end-systolic volume (r = 0.44 vs 0.17, p <0.01), and ejection fraction (r = 0.58 vs -0.03, p <0.01). The change in end-diastolic volume between baseline and follow-up with RT3DE (-4 +/- 20, p <0.01) was similar to that with MRI but was unrecognized by 2DE (4 +/- 19, p = 0.09). There was good test-retest and inter- and intraobserver correlation within RT3DE for volumes, ejection fraction, and mass. In conclusion, if sequential measurement of LV volumes is used to guide management decisions, 3DE appears preferable to 2DE.     

Volume measurement of the left ventricle in children with congenital heart defects: 3-dimensional echocardiography versus angiocardiography

BACKGROUND: Volume measurement of the left ventricle is currently done by 2-dimensional echocardiography or angiocardiography. However, for the calculation of volumes by these methods, geometrical assumptions must be made. For a precise ventricular volumetry, independent of mathematical assumptions, imaging techniques as the 3-dimensional echocardiography (3D-echo) are required, which permit the imaging of the real ventricular shape. The aim of the study was therefore to detect, whether 3D-echocardiography is suitable for left ventricular volumetry in children with congenital heart disease and whether the 3D-echocadiographically measured volumes correlate sufficiently well with angiocardiographically measured left ventricular volumes. METHODS: 102 children with congenital heart disease were investigated. For angiocardiographic left ventricular volume measurement Simpson's rule was used. Results were corrected with Lange's correction factors. The 3D-echo data sets were registered with a rotating transthoracic transducer. Ventricular volumes were calculated after manual planimetry by summation of the volumes of the single slices. RESULTS: The left ventricular volume could be calculated by 3D-echo in 83% of patients of all ages. In comparison to angiocardiography, the measured volumes were 0.6 +/- 3. 3 ml (0.9 +/- 25.8%) or 7.1 +/- 28.4 ml (7.4 +/- 12.1%) smaller during systole or diastole, respectively. The correlation coefficients r(2) were 0.89 for systolic and 0.93 for diastolic measurements after logarithmic transformation. Pressure or volume overload did not influence significantly the difference between the two methods. CONCLUSION: Transthoracic 3D-echocardiography with a rotating transmitter is feasible for volumetry of the left ventricle in most children. The volumes measured by 3D-echo were significantly smaller than those calculated from the angiocardiography by Simpson's rule. The measurements were not influenced by the kind of load of the ventricle. The correlation between the two methods is good.     

Accuracy and reproducibility of quantitation of left ventricular function by real-time three-dimensional echocardiography versus cardiac magnetic resonance

The aim of this study was to investigate the accuracy and reproducibility of the quantification of left ventricular (LV) function by real-time 3-dimensional echocardiography (RT3DE) using current state-of-the-art hardware and software. Compared with cardiac magnetic resonance (CMR), previous generations of hardware and software for RT3DE significantly underestimated LV volumes partly because of inherent factors such as limited spatial and temporal resolution. Also, RT3DE volumes were compared with short-axis CMR data, whereas a combined short-axis and long-axis analysis is known to be superior. Twenty-four subjects (mean age 51 +/- 12 years, 17 men) in sinus rhythm and with good to excellent 2-dimensional image quality underwent RT3DE and CMR within 1 day. The acquisition of RT3DE data was done with current state-of-the-art hardware and software. Two blinded experts performed off-line LV volume analysis. Global LV volumes were determined from semiautomated border detection on the basis of endocardial speckle tracking with biplane projections using QLAB version 6.0. Volumes derived by magnetic resonance imaging were quantified from combined short-axis and long-axis series. The volume-rate on RT3DE was 33 +/- 8 Hz (range 19 to 42). Excellent correlations were found (R(2) >/= 0.97) between CMR and RT3DE for global LV end-diastolic volume, LV end-systolic volume, the LV ejection fraction, and LV phase volumes (24 phases/cardiac cycle). Bland-Altman analyses showed mean differences of -7.1 ml, -4.2 ml, 0.2%, and -5.8 ml and 95% limits of agreement of +/-19.7 ml, +/-8.3 ml, +/-6.2%, and +/-15.4 ml for global LV end-diastolic volume, LV end-systolic volume, the LV ejection fraction, and LV phase volumes, respectively. Interobserver variability was 5.2% for global LV end-diastolic volume, 6.4% for LV end-systolic volume, and 7.6% for the LV ejection fraction. In conclusion, in patients with good acoustic windows, RT3DE using state-of-the-art technology provides accurate and reproducible measurements of global LV volumes, LV volume changes over time, and the LV ejection fraction.     

四维自动左室定量分析技术评价正常人左室容积及功能的初步研究

目的:探讨四维自动左室定量分析技术(4D AUTO LVQ)评价正常人左心室容积及功能的可行性及重复性.方法:在单心动周期(SB,single heart beat)及多心动周期(MB,multi-heartbeat)成像模式下分别采集20例正常志愿者左室三维图像(3-dimensional echocardiography),并分别使用4DAUTO LVQ技术测量左室舒张末容积(LVEDV)、左室收缩末容积(LVESV)及射血分数(EF),同时使用二维双平面Simpson's法及M型Teichholtz法检测同一组志愿者LVEDV、LVESV和EF.将4种方法所得的测值分别进行比较.结果:①M型测量的LVEDV测值与其他3种方法测值间差异有统计学意义(P<0.05),SB模式及MB模式下4D ATUO LVQ测量的LVEDV相关系数r为0.769;②SB、MB模式下4D ATUO LVQ方法测量的LVESV、双平面Simpson's法测量的LVESV测值与M型测值间差异均有统计学意义(P<0.05),SB与MB模式下测量的LVESV相关系数r为0.86;③SB、MB模式下测量的EF值与双平面Simpson's法及M型测值间差异均有统计学意义(P<0.05),SB与MB模式下测量的EF值相关系数r为0.428;Bland-Altman一致性分析表明4D AUTO LVQ在SB与MB模式下所测容积及EF值具有较高一致性.④SB模式下的3DE图像存储时间短于MB模式图像存储时间,差异有统计学意义(P<0.05);4D AUTO LVQ及Simpson's法后处理时间差异均无统计学意义(P>0.05).⑤SB与MB模式下4D AUTO LVQ测量LVEF观察者内变异系数分别为8.50%、6.50%,观察者间变异系数分别为7.75%、6.50%.结论:4D AUTO LVQ技术定量分析左室容积及EF有效、可行、快捷,具有临床应用价值.     

Experimental study of quantitative assessment of left ventricular mass with contrast enhanced real-time three-dimensional echocardiography

OBJECTIVES: To evaluate the feasibility and accuracy of measurement of left ventricular mass with intravenous contrast enhanced real-time three-dimensional (RT3D) echocardiography in the experimental setting. METHODS: RT3D echocardiography was performed in 13 open-chest mongrel dogs before and after intravenous infusion of a perfluorocarbon contrast agent. Left ventricular myocardium volume was measured according to the apical four-plane method provided by TomTec 4D cardio-View RT1.0 software, then the left ventricular mass was calculated as the myocardial volume multiplied by the relative density of myocardium. Correlative analysis and paired t-test were performed between left ventricular mass obtained from RT3D echocardiography and the anatomic measurements. RESULTS: Anatomic measurement of total left ventricular mass was 55.6 +/- 9.3 g, whereas RT3D echocardiographic calculation of left ventricular mass before and after intravenous perfluorocarbon contrast agent was 57.5 +/- 11.4 and 55.5 +/- 9.3 g, respectively. A significant correlation was observed between the RT3D echocardiographic estimates of total left ventricular mass and the corresponding anatomic measurements (r = 0.95). A strong correlation was found between RT3D echocardiographic estimates of left ventricular mass with perfluorocarbon contrast and the anatomic results (r = 0.99). Analysis of intraobserver and interobserver variability showed strong indexes of agreement in the measurement of left ventricular mass with pre and post-contrast RT3D echocardiography. CONCLUSIONS: Measurements of left ventricular mass derived from RT3D echocardiography with and without intravenous contrast showed a significant correlation with the anatomic results. Contrast enhanced RT3D echocardiography permitted better visualization of the endocardial border, which would provide a more accurate and reliable means of determining left ventricular myocardial mass in the experimental setting.     

Real time three-dimensional echocardiographic assessment of left ventricular function in heart failure patients: underestimation of left ventricular volume increases with the degree of dilatation

Background: Accurate quantification of left ventricular (LV) volumes and ejection fraction (EF) is of critical importance. Cardiac magnetic resonance (CMR) is considered as the reference and three-dimensional echocardiography (3DE) is an accurate method, but only few data are available in heart failure patients. We therefore sought to compare the accuracy of real time three-dimensional echocardiography (RT3DE) and two-dimensional echocardiography (2DE) for quantification of LV volumes and EF, relative to CMR imaging in an unselected population of heart failure patients. Methods and Results: We studied 24 patients (17 men, age 58 ± 15 years) with history of heart failure who underwent echocardiographic assessment of LV function (2DE, RT3DE) and CMR within a period of 24 hours. Mean LV end-diastolic volume (LVEDV) was 208 ± 109 mL (121 ± 64 mL/m(2) ) and mean LVEF was 31 ± 12.8%. 3DE data sets correlate well with CMR, particularly with respect to the EF (r: 0.8, 0.86, and 0.95; P < 0.0001 for LVEDV, LVESV, and EF, respectively) with small biases (-55 mL, -44 mL, 1.1%) and acceptable limits of agreement. RT3DE provides more accurate measurements of LVEF than 2DE (z= 2.1, P = 0.037) and lower variability. However, 3DE-derived LV volumes are significantly underestimated in patients with severe LV dilatation. In patients with LVEDV below 120 mL/m(2) , RT3DE is more accurate for volumes and EF evaluation. Conclusion: Compared with CMR, RT3DE is accurate for evaluation of EF and feasible in all our heart failure patients, at the expense of a significant underestimation of LV volumes, particularly when LVEDV is above 120 mL/m(2) .     

Accuracy of measurement of left ventricular volume and ejection fraction by new real-time three-dimensional echocardiography in patients with wall motion abnormalities secondary to myocardial infarction

Three-dimensional echocardiography is an ideal tool for the measurement of left ventricular (LV) volume because no geometric assumptions about LV shape are needed. The introduction of new real-time 3-dimensional echocardiography (RT3DE) has allowed rapid acquisition of a 3-dimensional dataset with good image quality. The purpose of this study was to examine the accuracy of RT3DE for the measurement of LV volume and ejection fraction in patients with wall motion abnormalities by using quantitative gated single-photon emission computed tomography (QGSPECT) as a reference standard. The study population consisted of 25 consecutive patients with wall motion abnormalities who underwent LV volume measurement by 2-dimensional echocardiography and by QGSPECT. LV volume and ejection fraction by RT3DE were measured offline by using the average rotation method. In 23 of 25 patients (92%), it was possible to measure 3-dimensional volume with RT3DE. RT3DE correlated well with QGSPECT in the measurement of end-diastolic volume and end-systolic volume (r = 0.97, mean difference 3.4 ml; r = 0.98, mean difference 2.0 ml, respectively), 2-dimensional echocardiography also correlated with QGSPECT but underestimated LV volume (r = 0.98, mean difference 21.1 ml; r = 0.98, mean difference 15.6 ml, respectively). Ejection fraction obtained by RT3DE had better agreement with that obtained by QGSPECT than that obtained by 2-dimensional echocardiography (r = 0.92, mean difference -0.2%; r = 0.89, mean difference -2.7%, respectively). RT3DE allows convenient and accurate estimation of LV volume and ejection fraction in patients with wall motion abnormalities.     

High-resolution transthoracic real-time three-dimensional echocardiography: quantitation of cardiac volumes and function using semi-automatic border detection and comparison with cardiac magnetic resonance imaging

OBJECTIVES: We sought to validate high-resolution transthoracic real-time (RT) three-dimensional echocardiography (3DE), in combination with a novel semi-automatic contour detection algorithm, for the assessment of left ventricular (LV) volumes and function in patients. BACKGROUND: Quantitative RT-3DE has been limited by impaired image quality and time-consuming manual data analysis. METHODS: Twenty-four subjects with abnormal (n = 14) or normal (n = 10) LVs were investigated. The results for end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) obtained by manual tracing were compared with the results determined by the semi-automatic border detection algorithm. Moreover, the results of the semi-automatic method were compared with volumes and EF obtained by cardiac magnetic resonance imaging (CMRI). RESULTS: Excellent correlation coefficients (r = 0.98 to 0.99) and low variability (EDV -1.3 +/- 8.6 ml; ESV -0.2 +/- 5.4 ml; EF -0.1 +/- 2.7%; p = NS) were observed between the semi-automatically and manually assessed data. The RT-3DE data correlated highly with CMRI (r = 0.98). However, LV volumes were underestimated by RT-3DE compared with CMRI (EDV -13.6 +/- 18.9 ml, p = 0.002; ESV -12.8 +/- 20.5 ml, p = 0.005). The difference for EF was not significant between the two methods (EF 0.9 +/- 4.4%, p = NS). Observer variability was acceptable, and repeatability of the method was excellent. CONCLUSIONS: The RT-3DE, in combination with a semi-automatic contour tracing algorithm, allows accurate determination of cardiac volumes and function compared with both manual tracing and CMRI. High repeatability suggests applicability of the method for the serial follow-up of patients with cardiac disease.     

Validation of real-time three-dimensional echocardiography for quantifying left ventricular volumes in the presence of a left ventricular aneurysm: in vitro and in vivo studies

OBJECTIVES: To validate the accuracy of real-time three-dimensional echocardiography (RT3DE) for quantifying aneurysmal left ventricular (LV) volumes. BACKGROUND: Conventional two-dimensional echocardiography (2DE) has limitations when applied for quantification of LV volumes in patients with LV aneurysms. METHODS: Seven aneurysmal balloons, 15 sheep (5 with chronic LV aneurysms and 10 without LV aneurysms) during 60 different hemodynamic conditions and 29 patients (13 with chronic LV aneurysms and 16 with normal LV) underwent RT3DE and 2DE. Electromagnetic flow meters and magnetic resonance imaging (MRI) served as reference standards in the animals and in the patients, respectively. Rotated apical six-plane method with multiplanar Simpson's rule and apical biplane Simpson's rule were used to determine LV volumes by RT3DE and 2DE, respectively. RESULTS: Both RT3DE and 2DE correlated well with actual volumes for aneurysmal balloons. However, a significantly smaller mean difference (MD) was found between RT3DE and actual volumes (-7 ml for RT3DE vs. 22 ml for 2DE, p = 0.0002). Excellent correlation and agreement between RT3DE and electromagnetic flow meters for LV stroke volumes for animals with aneurysms were observed, while 2DE showed lesser correlation and agreement (r = 0.97, MD = -1.0 ml vs. r = 0.76, MD = 4.4 ml). In patients with LV aneurysms, better correlation and agreement between RT3DE and MRI for LV volumes were obtained (r = 0.99, MD = -28 ml) than between 2DE and MRI (r = 0.91, MD = -49 ml). CONCLUSIONS: For geometrically asymmetric LVs associated with ventricular aneurysms, RT3DE can accurately quantify LV volumes.     

Improvement in forward cardiac output without a change in ejection fraction during nitroglycerin therapy in patients with functional mitral regurgitation

Left ventricular volumes and forward aortic flow were measured using combined two-dimensional echocardiography and doppler cardiography in seven patients with decompensated congestive heart failure and functional mitral regurgitation prior to and during intravenous administration of nitroglycerin. Total stroke volume was calculated from the difference between end-diastolic and end-systolic volumes, and regurgitant mitral volume from the difference between total stroke volume and forward aortic flow. Regurgitant mitral volume fell from 19 +/- 9 to 3 +/- 3 mL/beat (p less than 0.001), while forward stroke volume increased from 35 +/- 8 to 45 +/- 9 mL/beat (p less than 0.001). The changes were well correlated (r = 0.8, p less than 0.001). Total stroke volume decreased from 54 +/- 12 to 48 +/- 6 mL/beat (p less than 0.05), and ventricular end-diastolic volume from 173 +/- 66 to 158 +/- 66 mL (p less than 0.05). Left ventricular ejection fraction did not change significantly: 33 +/- 9% vs 32 +/- 9% (NS). Thus, in patients with severe congestive heart failure and functional mitral regurgitation, intravenous nitroglycerin redistributes blood flow within the heart by decreasing mitral regurgitation and increasing forward aortic flow, without affecting left ventricular ejection fraction.     

Comparison of contrast agent-enhanced versus non-contrast agent-enhanced real-time three-dimensional echocardiography for analysis of left ventricular systolic function

Ultrasound contrast has shown to improve endocardial border definition. The purpose of this study was to evaluate the value of contrast agent-enhanced versus non-contrast agent-enhanced real-time 3-dimensional echocardiography (RT3DE) for the assessment of left ventricular (LV) volumes and ejection fraction. Thirty-nine unselected patients underwent RT3DE with and without SonoVue contrast agent enhancement and magnetic resonance imaging (MRI) on the same day. An image quality index was calculated by grading all 16 individual LV segments on a scale of 0 to 4: 0, not visible; 1, poor; 2, moderate; 3, good; and 4, excellent. The 3-dimensional data sets were analyzed offline using dedicated TomTec analysis software. By manual tracing, LV end-systolic volume, LV end-diastolic volume, and LV ejection fraction were calculated. After contrast agent enhancement, mean image quality index improved from 2.4 +/- 1.0 to 3.0 +/- 0.9 (p <0.001). Contrast agent-enhanced RT3DE measurements showed better correlation with MRI (LV end-diastolic volume, r = 0.97 vs 0.86; LV end-systolic volume, r = 0.96 vs 0.94; LV ejection fraction, r = 0.94 vs 0.81). The limits of agreement (Bland-Altman analysis) showed a similar bias for RT3DE images with and without contrast agent but with smaller limits of agreement for contrast agent-enhanced RT3DE. Also, inter- and intraobserver variabilities decreased. In a subgroup, patients with poor to moderate image quality showed an improvement in agreement after administration of contrast agent (+/-24.4% to +/-12.7%) to the same level as patients with moderate to good image quality without contrast agent (+/-10.4%). In conclusion, contrast agent-enhanced RT3DE is more accurate in assessment of LV function as evidenced by better correlation and narrower limits of agreement compared with MRI, as well as lower intra- and interobserver variabilities.     

Effect of isotonic exercise training on left ventricular volume during upright exercise

To determine the changes in left ventricular volume and their time course during exercise we studied 30 runners. Left ventricular end-diastolic and end-systolic volumes were measured from biapical two-dimensional echocardiograms recorded during graded upright bicycle exercise. The validity of this echocardiographic technique was assessed by comparing measurements at rest and exercise with results obtained by gated equilibrium radionuclide angiography in 10 patients with coronary artery disease. Although the absolute volume measurements were lower by echocardiography, ejection fraction was not significantly different and the directional changes in volume during exercise were comparable. In the runners, resting left ventricular end-diastolic volume measurements by echocardiography correlated with their maximum bicycle exercise endurance times (r = .80). Left ventricular end-diastolic volume, stroke volume, and ejection fraction increased during exercise with the most marked changes occurring in the first half of exercise. Systolic blood pressure/end-systolic volume (SBP/ESV) also increased during exercise, but the largest change occurred during the second half of exercise. Left ventricular volumes were larger in the 12 competitive marathon runners (maximum exercise duration greater than or equal to 27 min) as compared with the 18 noncompetitive runners (exercise duration less than or equal to 23 min): resting end-diastolic volume 130 +/- 29 (SD) ml vs 87 +/- 20 ml (p less than .001), respectively. During exercise the competitive runners exhibited a larger increase in end-diastolic volume and the noncompetitive athletes showed a greater increase in SBP/ESV. Therefore, highly trained competitive marathon runners make greater use of the less energy-consuming Frank-Starling mechanism to accomplish high levels of isotonic exercise performance as compared with less well-trained runners.     

Noninvasive evaluation of global left ventricular function with use of cine nuclear magnetic resonance

Previous reports have validated the accuracy of nuclear magnetic resonance (NMR) imaging for quantitating ventricular volumes and myocardial mass. In this study, a new rapid NMR imaging method, cine NMR imaging, was used to compare left ventricular volumes determined from the transverse plane and short-axis plane in healthy volunteers and patients with dilated cardiomyopathy. With use of the short-axis plane, left ventricular mass at end-systole and end-diastole were determined and left ventricular systolic wall thickening at three different levels was assessed. For validation in the current study, cine NMR imaging and two-dimensional echocardiographic measurements of left ventricular volumes were correlated. Left ventricular volumes of the normal volunteers (end-systolic volume = 34 +/- 3.8 ml, end-diastolic volume = 90.4 +/- 7.2 ml) and patients with cardiomyopathy (end-systolic volume = 173 +/- 28.3 ml, end-diastolic volume = 219.5 +/- 29.6 ml) obtained in the transverse plane were nearly identical to those obtained in the short-axis plane (normal volunteers, end-systolic volume = 30.3 +/- 3.5 ml, end-diastolic volume = 84.7 +/- 7.0 ml and patients with cardiomyopathy, end-systolic volume = 179.1 +/- 27.8 ml, end-diastolic volume = 227 +/- 30.9 ml) and correlated highly (r = 0.91) with volumes obtained by two-dimensional echocardiography. Assessment of left ventricular mass over a broad range using cine NMR imaging in a short-axis plane was identical at end-systole (normal volunteers, 117 +/- 10 g; patients with cardiomyopathy, 202 +/- 20 g) and end-diastole (normal volunteers, 115 +/- 10 g; patients with cardiomyopathy, 194 +/- 21 g).(ABSTRACT TRUNCATED AT 250 WORDS)     

New insight into left ventricular function in tricuspid atresia after total cavopulmonary connection: a three-dimensional echocardiographic study

BACKGROUND: In patients with tricuspid atresia palliated by construction of a total cavopulmonary connection, both pulmonary and systemic circulations depend on the performance of the dominant left ventricle. When estimating the volume of such ventricles using cross-sectional echocardiography, it is necessary to make assumptions concerning the geometry of the ventricular shape. This is avoided by three-dimensional echocardiography, which provides direct volumetric data. Our purpose was to apply this new method to quantify left ventricular volumes and function in patients with tricuspid atresia after construction of a total cavopulmonary connection. METHODS: We studied ten patients (median age: 8 years) with tricuspid atresia who had undergone a total cavopulmonary connection, comparing them with 10 normal children matched for age, sex and size. The three-dimensional echocardiography was performed with electrocardiographic and respiratory gating. A new transthoracic integrated probe designed for small children was used with a rotational scanning increment of 3 degrees. The 60 slices obtained from the ventricular cavity were stored and formatted in a commercial system (TomTec). End-diastolic and end-systolic volumes, stroke volume and ejection fraction were calculated after manual tracing of the endocardial surfaces. The volumes were indexed to the body surface area. RESULTS: As seen in the reconstructions, the dominant left ventricle in tricuspid atresia had a spherical shape, whereas the normal left ventricle is oblong. The left ventricular volumes and function in tricuspid atresia were 54+/-4 ml/m2 (end-diastolic volume), 28+/-3 ml/m2 (end-systolic volume), 26+/-7 ml/m2 (stroke volume) and 48+/-6% (ejection fraction). These volumes were not different from those obtained in the controls (p = NS). The left ventricular stroke volume and ejection fraction in 10 patients with tricuspid atresia were lower than those calculated for the controls (p < 0.05). CONCLUSIONS: Three-dimensional echocardiography provides a quantitative insight into the pathophysiologic function of the dominant left ventricle in tricuspid atresia after construction of a total cavopulmonary connection.     

Rapid and accurate measurement of LV mass by biplane real-time 3D echocardiography in patients with concentric LV hypertrophy: comparison to CMR.

AIMS: To evaluate the accuracy of real-time three-dimensional echocardiography (RT3DE) using a biplane and multiplane method in determining left ventricular (LV) mass compared to cardiac magnetic resonance imaging (CMR). METHODS AND RESULTS: LV mass was measured in 18 adult patients with congenital aortic stenosis using CMR and echocardiography (M-mode, two-dimensional echocardiography (2DE), and RT3DE). RT3DE data were analysed using a biplane and multiplane method. No geometric assumptions were necessary using the multiplane RT3DE method. With regard to biplane or multiplane RT3DE, no tendency of over- or underestimation of LV mass was observed. Pearson's correlation coefficients for RT3DE versus CMR were 0.84 and 0.90 for the biplane and multiplane method, respectively. In addition, the accuracy of both RT3DE methods were comparable (Fisher's R-to-Z transformation: Z = 0.69, P = NS). Finally, off-line analysis using biplane RT3DE was significantly faster than multiplane RT3DE (3.8 +/- 1.2 vs. 7.8 +/- 1.7 minutes, P < 0.001). CONCLUSIONS: Biplane RT3DE provided an accurate estimate of LV mass in patients with concentric left ventricular hypertrophy, which was not improved by multiplane RT3DE. The accuracy and speed of analysis renders biplane RT3DE an attractive tool in daily clinical practice for assessing the degree of LV hypertrophy.     

Two-dimensional echocardiographic determination of ventricular volumes in the fetal heart. Validation studies in fetal lambs

The determination of ventricular volumes in the fetal heart from two-dimensional echocardiography (2DE) may give a better estimate of fetal ventricular size than simple diameter measurements, but the accuracy of this method has not been established. In fetal lambs, we tested whether ventricular volume calculations from 2DE using a biplane Simpson's rule algorithm are accurate. Calculations of left and right ventricular end-diastolic volumes from 2DE were compared with cast volumes of these ventricles. Also, at different levels of left atrial pressure, left ventricular stroke volumes calculated from 2DE were compared with stroke volumes measured simultaneously by an electromagnetic flowmeter. There was a good correlation between volumes determined from 2DE (y axis) and from casts (x axis) for both the left (r = 0.92; y = 0.2 + 1.1x; SEE = 0.19 ml) and right ventricle (r = 0.90; y = 0.7 + 0.9x; SEE = 0.21 ml). Left ventricular stroke volumes calculated from 2DE correlated well with those measured by the electromagnetic flowmeter (r = 0.87; y = 0.2 + 0.9x; SEE = 0.27 ml). Thus, calculation of fetal ventricular volumes from 2DE images using a biplane Simpson's rule method is feasible and accurate.     

Unfavourable left ventricular remodelling in patients with dobutamine-inducible ischaemia after acute myocardial infarction.

AIMS: Aim of the study was to assess the role of early inducible ischaemia for determining left ventricular remodelling in patients with acute myocardial infarction. METHODS AND RESULTS: In 179 consecutive patients with first myocardial infarction the occurrence of new wall motion abnormalities during dobutamine stress echocardiography at discharge was related to the left ventricular volume changes at 6 months. Left ventricular end-diastolic and end-systolic index volumes (mL/m(2)) were echocardiographically detected at discharge and at 6 months and the relative changes were calculated. The study population consisted of 105 patients without and 74 patients with inducible ischaemia; of these, 46 patients had > or =4 ischaemic segments. At 6 months, the end-diastolic index volume increased in patients with inducible ischaemia compared to patients without (+7.5+/-11.2 vs -0.1+/-10.2 mL/m(2); P=0.0049) and final mean end-diastolic volume was greater in patients with inducible ischaemia than without (70.8+/-16.0 vs 61.1+/-17.0 mL/m(2); P=0.0012). The end-systolic volume increased at 6 months in patients with inducible ischaemia and it decreased in patients without (+2.8+/-8.6 vs -1.4+/-7.8 mL/m(2); P=0.021). At the multivariate analysis, inducible ischaemia in > or =4 segments (odds ratio=6.43), the wall motion score index at the peak of dobutamine infusion (odds ratio=1.14) and the end-systolic index volume at discharge (odds ratio=1.06) were independent predictors of subsequent left ventricular end-diastolic index volume increase > or =15 mL/m(2). CONCLUSION: In patients with first myocardial infarction the presence and the severity of inducible ischaemia, as detected by dobutamine stress echocardiography at discharge, indicates an unfavourable left ventricular remodelling.     

Freehand three-dimensional echocardiography with rotational scanning for measurements of left ventricular volume and ejection fraction in patients with coronary artery disease

BACKGROUND: Measurement of left ventricular (LV) volumes and ejection fraction (EF) is important in managing patients with coronary artery disease (CAD). Introduction of free-hand three-dimensional echocardiography (3DE) system which is equipped with small magnetic tracking system and average rotational geometry for LV volumes may provide easy and accurate quantification of LV systolic function in CAD patients. PURPOSE: To evaluate the feasibility and accuracy of LV volumes and EF measurement by free-hand 3DE with rotational geometry in patients with CAD. METHODS AND RESULTS: The study subjects consisted of consecutive 25 patients with CAD who were scheduled for quantitative gated single-photon emission computed tomography (QGS). LV end-diastolic volume (EDV), end-systolic volume (ESV), and EF were determined by conventional two-dimensional echocardiography (2DE), 3DE, and QGS. Three-dimensional echocardiography data acquisition and analysis were possible in 22 of 25 subjects (feasibility 88%). In this 3DE system, image acquisition time was 2 minutes, and 5 minutes were needed for off-line analysis of LV volumes and EF. Correlations and the limits of agreement between 3DE and QGS (r = 0.97, 0.0 +/- 9.1 ml for EDV, r = 0.99, 0.0 +/- 5.0 ml for ESV, and r = 0.97, 0.5 +/- 3.3% for EF, respectively) were superior to those between 2DE and QGS (r = 0.85, 12.6 +/- 26.8 ml for EDV, r = 0.85, 9.7 +/- 26.1 ml for ESV, and r = 0.90, -1.3 +/- 6.9% for EF, respectively). Inter- and intra-observer variabilities of 3DE were smaller than that of 2DE (5% vs 10%, 5% vs 10% for EDV, 6% vs 13%, 5% vs 9% for ESV, and 4% vs 11%, 4% vs 6% for EF, respectively). CONCLUSION: Three-dimensional echocardiography using magnetic tracking system and average rotational geometry offered a feasible and accurate method for quantification of LV volumes and EF in patients with CAD.     

Echocardiographic online quantification of left ventricular systolic function in children: comparison with conventional off-line determination

Accurate and efficient echocardiographic on-line determination of left ventricular volume would be advantageous in the care of children with congenital heart disease and children with hemodynamic instability. The prospective study was performed to evaluate the clinical usefulness of the on-line automatic border detection system (acoustic quantification: AQ) for determination of left ventricular volumes and ejection fraction in comparison to the conventional off-line method (manual tracing). 107 patients were enrolled in the study. The ages ranged from 0.1 to 18.8 years (mean 8.3 +/- 5.6). All patients were studied in the apical four-chamber plane for acoustic quantification (AQ) and manual tracing as well. Left ventricular volumes were determined using the mono-plane Simpson's rule. Left ventricular end-diastolic volumes obtained by AQ correlated well but were slightly underestimated compared to those determined by manual tracing (r = 0.99). Left ventricular endsystolic volumes by AQ correlated well but were also slightly underestimated compared to those obtained by manual tracing (r = 0.98). Mean ejection fraction was 61.1 +/- 6.8% by AQ compared with 61.5 +/- 5.9% by manual tracing. Linear regression analysis demonstrated good correlation: y = 0.77x + 14.1, r = 0.89; p < 0.001. Measurement of left ventricular volumes and ejection fraction by AQ using automatic border detection compares well with measurements done by manual tracing. However, AQ tends to underestimate to some degree. The time necessary for acquisition of data was similar in both methods. AQ seems to be a promising method for real-time estimation of left ventricular volume, even in children.