Tissue Doppler Imaging Measurement of Left Ventricular Systolic Function in Children: Mitral Annular Displacement Index Is Superior to Peak Velocity
ABSTRACT Doppler tissue imaging (DTI)-derived mitral annular systolic peak S-wave velocity (S') correlates with left ventricular (LV) ejection fraction (EF). The authors hypothesized that DTI mitral annular displacement, which is equal to the velocity-time integral of the DTI S' wave, might be superior to S' to analyze LV systolic function. Because S' varies with age, it was expressed as Sz, the z-score variance from normal S' for each subject. Because displacement varies with heart size, it was expressed as a displacement index, or the DTI S'-wave velocity-time integral divided by the end-diastolic distance from the mitral annulus to the LV apex. The aims of this study were to (1) measure the accuracy, sensitivity, specificity, and positive and negative predictive values of displacement index compared with Sz to detect systolic dysfunction; (2) compare displacement index with other quantitative parameters of longitudinal systolic function, including color DTI-derived strain and two-dimensional speckle-tracking echocardiography (2D)-derived mitral annular displacement and strain; and (3) determine the effects of age, heart rate (HR), and body surface area (BSA) on displacement index.
Displacement index and Sz results were compared with EF and with each other using statistical tests, including independent t tests, linear regression, receiver operating characteristic curve analysis, and 2 x 2 probability tables. Displacement index was also compared with other parameters of longitudinal systolic function, age, HR, and BSA using regression analysis.
Forty-six patients had normal (EF > or = 55%) and 34 abnormal (EF < 55%) LV function. Groups were statistically equivalent (P > .05) for age, HR, and BSA and statistically different (P < .001) for all measured parameters of systolic function. Displacement index and EF were linearly related. Receiver operating characteristic curve analysis showed the sensitivity of displacement index to be greater than that of Sz throughout the study range. Probability table analysis demonstrated that for predicting EF < 55%, the sensitivity, accuracy, and negative predictive value were greater for displacement index than for Sz. Displacement index was linearly correlated with 2D mitral annular longitudinal displacement, 2D LV basal segment longitudinal strain, and color DTI LV basal segment longitudinal strain. Displacement index was not affected by age, HR, or BSA.
Displacement index is linearly related to EF and also to other parameters of longitudinal systolic function. Displacement index has some advantages over Sz for assessing ventricular systolic function and should prove useful in measuring longitudinal and global LV systolic function.
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ABSTRACT: Speckle tracking echocardiography (STE)-derived mitral annular displacement (MAD) utilizes the speckle tracking technique to measure strain vectors, which provides accurate estimates of left ventricular ejection fraction (LVEF). Here, we investigated a link between STE-derived MAD and LVEF in patients with different heart diseases and evaluated its clinical usefulness. This study included 266 outpatients and 84 controls. Of the study patients, 52 patients had ischemic heart disease (IHD), 37 patients had dilated cardiomyopathy (DCM), 34 patients had hypertrophic cardiomyopathy (HCM), 74 patients had valvular heart disease (VHD), and 69 patients had hypertensive heart disease (HHD). STE continuously tracked annular motion throughout the cardiac cycle in the apical 4- and 2-chamber views. In all participants, the curvilinear relationship was found between STE-derived MAD and LVEF (R(2)=0.642). The strong correlation between STE-derived MAD and LVEF was also found in the patients with IHD (R(2)=0.733, p=0.001) and in those with DCM (R(2)=0.614, p=0.008). However, such a correlation was not found in the patients with HCM, VHD, or HHD. The specificity in the correlation between STE-derived MAD and LVEF was found in patients with each heart disease, which should be taken into account when assessing these parameters.Journal of Cardiology 03/2012; 60(1):55-60. DOI:10.1016/j.jjcc.2012.01.014 · 2.57 Impact Factor
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ABSTRACT: Summary form only given. The authors examine internal representations of a stochastic vector machine (SVM) and compare its learning ability with that of the backpropagation (BP) model through the experiments of handwritten Chinese character recognition. The experimental results show two facts. One is that local or distributed representation of input patterns is developed, depending on the structure of SVM. The other is that the recognition rate of the SVM is almost equal to that of the BP model, so its learning ability can be considered to be comparable to that of BP model
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ABSTRACT: Left ventricular (LV) ejection fraction (EF) by transthoracic two-dimensional echocardiography is time-intensive and highly dependent on image quality. Mitral annular displacement (MAD) qualitatively correlates with EF and can be measured in patients with poor image quality and dropout. The authors hypothesized that speckle-tracking echocardiography (STE)-derived MAD could quantify EF accurately and tested this hypothesis using cardiac magnetic resonance (CMR) as a reference. One hundred eighteen patients undergoing clinical transthoracic echocardiography were screened, and 110 whose mitral annuli was sufficiently well-defined irrespective of LV endocardial visualization underwent CMR within 6 days (85 of 110 in 1 day). Reference CMR EF values were obtained using standard methodology. STE was used to track annular motion throughout the cardiac cycle in the apical 2-chamber and 4-chamber views. To establish the relationship between MAD and CMR EF and to obtain a formula to estimate EF from MAD, regression analysis was performed in a study group of 60 patients with a wide range of EFs. This formula was then used in an independent test group of 50 patients by comparing estimated MAD EF against CMR EF values using Pearson's correlation and Bland-Altman analyses. In the study group, STE MAD correlated highly with CMR EF and resulted in a formula relating MAD to EF. In the test group, estimated EF correlated well with CMR EF (4-chamber, R(2) = 0.64; 2-chamber, R(2) = 0.55), with near-zero bias and acceptable limits of agreement. Intraobserver and interobserver variability were between 5.8% and 12.7%. STE MAD is a clinically useful tool for quick, easy, robust, and accurate estimates of EF irrespective of LV endocardial definition.Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 03/2010; 23(5):511-5. DOI:10.1016/j.echo.2010.03.003 · 3.99 Impact Factor