Browsing by Author "Roberto M. Lang"

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    Effects of frame rate on 3D speckle tracking based measurements of myocardial deformation
    (2012-12-01) Chattanong Yodwut; Lynn Weinert; Berthold Klas; Roberto M. Lang; Victor Mor-Avi; University of Chicago Medical Center; Mahidol University; TomTec Imaging Systems
    Myocardial strain has been shown useful in the evaluation of left ventricular (LV) function using 2D and 3D speckle tracking echocardiography (STE). 3D STE is potentially more accurate, because it is not affected by through-plane motion. While with 2D STE, high frame rates are necessary because speckles may move out of the imaging plane, we hypothesized that they should be tracked with 3D STE, even with lower frame rates, because they always remain within the scan volume. Sixteen normal volunteers underwent 2D (at 62±9 fps) and 3D imaging, which was performed at 4 different frame rates, achieved by varying the number of beats used for volume acquisition (6, 4, 2 and 1). The principal components of strain and the corresponding strain-rates were calculated from both 2D and 3D images. Strain and strain-rates were the same for 3D STE with 6- and 4-beat datasets, corresponding to 25 and 18 fps, respectively, and were not significantly lower than 2D STE-derived values, indicating that there was no loss of information due to lower frame rates. In contrast, 3D STE with 1- and 2-beat datasets, corresponding to 5 and 10 fps, resulted in significantly lower values. 3D STE strains and strain-rates are not compromised by low frame rates, when derived from 18 or 25 fps datasets, but are underestimated with lower frame rates. © 2012 CCAL.
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    Effects of frame rate on three-dimensional speckle-tracking-based measurements of myocardial deformation
    (2012-09-01) Chattanong Yodwut; Lynn Weinert; Berthold Klas; Roberto M. Lang; Victor Mor-Avi; University of Chicago; Mahidol University; TomTec Imaging Systems
    Background: Myocardial strain is useful in the evaluation of left ventricular function using high-frame rate two-dimensional (2D) speckle-tracking echocardiography (STE). Three-dimensional (3D) STE allows 3D measurement of myocardial deformation, which is potentially more accurate, because it is not affected by through-plane motion. However, the low frame rates of 3D STE are a potential limitation that has not been studied to date. Whereas with 2D STE, high frame rates are necessary because speckles may move out of the imaging plane, it was hypothesized that because they always remain within the scan volume, they should be tracked with 3D STE, even if frame rates are considerably lower. Methods: Twenty-seven subjects were studied, including 16 normal volunteers and 11 patients with nonischemic dilated cardiomyopathy, who underwent 2D (frame rate, 62 ± 9 frames/sec) and 3D echocardiographic imaging. In normal subjects, 3D imaging was performed at four different frame rates, achieved by varying the number of beats used for full-volume acquisition (six, four, two, and one). In the patients with dilated cardiomyopathy, 3D imaging was performed using a four-beat acquisition. The principal components of strain and the corresponding strain rates were calculated in 16 myocardial segments and averaged. Both 2D and 3D images were analyzed using TomTec software to avoid analysis-related differences. Results: In normal subjects, strain and strain rate values were the same for 3D STE with six-beat and four-beat full-volume data sets, corresponding to 25 and 18 frames/sec, respectively. In contrast, 3D STE with one-beat and two-beat data sets, corresponding to 5 and 10 frames/sec, respectively, resulted in significantly lower values. Strain and strain rate values derived from six-beat and four-beat 3D data sets were not significantly lower than 2D STE-derived values, indicating that there was no loss of information due to lower frame rates. In patients with dilated cardiomyopathy, both 2D STE-derived and 3D STE-derived strain values were significantly reduced compared with normal hearts. The differences between 2D STE-derived and 3D STE-derived strain values echoed those noted in the normal subjects. Conclusions: Three-dimensional speckle-tracking echocardiographic assessment of myocardial deformation is not compromised by low frame rates when derived from 18 or 25 frames/sec data sets but is underestimated with lower frame rates.
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    Evaluation of myocardial deformation in patients with sickle cell disease and preserved ejection fraction using three-dimensional speckle tracking echocardiography
    (2012-09-01) Homaa Ahmad; Etienne Gayat; Chattanong Yodwut; M. Cristina Abduch; Amit R. Patel; Lynn Weinert; Ankit Desai; Wendy Tsang; Joe G N Garcia; Roberto M. Lang; Victor Mor-Avi; University of Chicago; Hopital Saint-Louis; Instituto do Coracao do Hospital das Clinicas; Mahidol University; University of Illinois at Chicago
    Background: Sickle cell disease (SCD) is a hemoglobinopathy that affects one in 500 African Americans. Although it is well established that patients with SCD have left ventricular (LV) diastolic dysfunction, it is not clear whether they have subtle LV systolic dysfunction despite preserved ejection fraction (EF). We used three-dimensional speckle tracking echocardiography (3DSTE) to assess changes in both systolic and diastolic LV function in SCD. Methods: Transthoracic real time 3D images were obtained (Philips iE33) in 56 subjects, including 28 stable outpatients with SCD (age 33 ± 7 years) and 28 normal controls (age 35 ± 9 years). 3DSTE was performed using prototype software (4DLV Analysis, TomTec) to obtain LV volume and deformation time curves, from which indices of systolic and diastolic LV function were calculated. Results: In SCD patients, 3DSTE-derived LV filling parameters were significantly different from normal controls, reflecting an increase in both rapid and atrial filling volumes and prolonged active relaxation, depicted by a decrease in filling volume fractions at fixed times and an increase in rapid filling duration. Global LV systolic function was not only preserved but increased compared to controls, as reflected by significantly increased global longitudinal strain. Importantly, twist angle and torsion as well as radial and circumferential components of 3D strain were similar in both groups. Conclusions: 3DSTE was able to confirm diastolic dysfunction, as expected in some patients with SCD. However, 3DSTE strain analysis did not reveal any changes in LV systolic function. These findings provide novel insight into the pathophysiology of the cardiovascular complications of SCD. © 2012, Wiley Periodicals, Inc.
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    Mechanistic insights and characterization of sickle cell disease-associated cardiomyopathy
    (2014-01-01) Ankit A. Desai; Amit R. Patel; Homaa Ahmad; John V. Groth; Thejasvi Thiruvoipati; Kristen Turner; Chattanong Yodwut; Peter Czobor; Nicole Artz; Roberto F. MacHado; Joe G N Garcia; Roberto M. Lang; University of Illinois at Chicago; University of Chicago Medical Center; Ochsner Medical Center - New Orleans; Loyola University Medical Center; Mahidol University; Unity Point Health; University of Arizona
    Background-Cardiovascular disease is an important cause of morbidity and mortality in sickle cell disease (SCD). We sought to characterize sickle cell cardiomyopathy using multimodality noninvasive cardiovascular testing and identify potential causative mechanisms. Methods and Results-Stable adults with SCD (n=38) and healthy controls (n=13) prospectively underwent same day multiparametric cardiovascular magnetic resonance (cine, T2* iron, vasodilator frst pass myocardial perfusion, and late gadolinium enhancement imaging), transthoracic echocardiography, and applanation tonometry. Compared with controls, patients with SCD had severe dilation of the left ventricle (124±27 vs 79±12 mL/m2), right ventricle (127±28 vs 83±14 mL/m2), left atrium (65±16 vs 41±9 mL/m2), and right atrium (78±17 vs 56±17 mL/m 2; P<0.01 for all). Patients with SCD also had a 21% lower myocardial perfusion reserve index than control subjects (1.47±0.34 vs 1.87±0.37; P=0.034). A signifcant subset of patients with SCD (25%) had evidence of late gadolinium enhancement, whereas only 1 patient had evidence of myocardial iron overload. Diastolic dysfunction was present in 26% of patients with SCD compared with 8% in controls. Estimated flling pressures (E/e′, 9.3±2.7 vs 7.3±2.0; P=0.0288) were higher in patients with SCD. Left ventricular dilation and the presence of late gadolinium enhancement were inversely correlated to hepatic T2* times (ie, hepatic iron overload because of frequent blood transfusions; P<0.05 for both), whereas diastolic dysfunction and increased flling pressures were correlated to aortic stiffness (augmentation pressure and index, P<0.05 for all). Conclusions-Sickle cell cardiomyopathy is characterized by 4-chamber dilation and in some patients myocardial fbrosis, abnormal perfusion reserve, diastolic dysfunction, and only rarely myocardial iron overload. Left ventricular dilation and myocardial fbrosis are associated with increased blood transfusion requirements, whereas left ventricular diastolic dysfunction is predominantly correlated with increased aortic stiffness. © 2014 American Heart Association, Inc.
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    Noninvasive estimation of left ventricular compliance using three-dimensional echocardiography
    (2012-06-01) Etienne Gayat; Victor Mor-Avi; Lynn Weinert; Sanjiv J. Shah; Chattanong Yodwut; Roberto M. Lang; University of Chicago Medical Center; Hopital Saint-Louis; Northwestern Memorial Hospital; Mahidol University
    Background: Left ventricular (LV) compliance is an important determinant of LV function and can be affected by a variety of cardiovascular conditions. In particular, diastolic dysfunction is associated with altered LV compliance. However, the evaluation of LV compliance is complex. Although the end-diastolic pressure-volume relationship (EDPVR) allows a direct, accurate evaluation of LV compliance, it requires invasive measurements. The aim of this study was to test the feasibility of noninvasive estimation of the EDPVR as a tool to evaluate LV compliance using three-dimensional echocardiography. Methods: Sixty-eight subjects were studied, including 23 normal controls, 22 patients with increased LV compliance due to dilated cardiomyopathy, and 23 patients with reduced LV compliance secondary to isolated diastolic dysfunction as defined using current American Society of Echocardiography guidelines. The EDPVR was calculated for each subject using a nonlinear model with echocardiographic estimates of end-diastolic pressure and volume. For both the isolated diastolic dysfunction and dilated cardiomyopathy groups, predicted end-diastolic volumes at predetermined pressure values (5, 10, 20, and 30 mm Hg) were compared with values in normal controls. Results: Compared with controls, noninvasive estimates of the EDPVR resulted in predicted end-diastolic volumes that were lower in the isolated diastolic dysfunction group and higher in the dilated cardiomyopathy group (P < .0001 for all four pressure levels). In addition, a stepwise trend of decreased compliance was noted for the different grades of diastolic dysfunction. Conclusions: This is the first study to demonstrate the feasibility of noninvasive estimation of the LV EDPVR and its ability to differentiate normal from abnormal LV compliance using three-dimensional echocardiography. Copyright © 2012 by the American Society of Echocardiography.
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    Noninvasive quantification of left ventricular elastance and ventricular-arterial coupling using three-dimensional echocardiography and arterial tonometry
    (2011-11-01) Etienne Gayat; Victor Mor-Avi; Lynn Weinert; Chattanong Yodwut; Roberto M. Lang; University of Chicago Medical Center; Hopital Saint-Louis; Mahidol University
    Most techniques previously used to assess left ventricular (LV) end-systolic elastance (E es ) and ventricular-arterial coupling (Clv-a) relied on invasive measurements and data acquisition over a wide range of loading conditions. Our goals were to 1) assess the feasibility of noninvasive assessment of E es and Clv-a using real-time three-dimensional echocardiography (RT3DE) and arterial tonometry; 2) test the ability of this approach to detect changes in LV contractility; and 3) study its reproducibility. We studied pharmacologically induced changes in inotropic state (5 and 10 (xg·kg _1 ·min _1 dobutamine) in normal volunteers (N = 8) and compared 10 normal volunteers with 10 patients with dilated cardiomyopathy (DCM; ejection fraction < 35%). RT3DE LV images, calibrated carotid artery tonometry, and Doppler tracings were obtained to noninvasively estimate E es and Clv-a, using two alternative calculations. Dobutamine caused a significant stepwise increase in blood pressure, heart rate, ejection fraction, and E es and a decreased Clv-a. In patients with DCM, E es was significantly reduced and C L v-a elevated, compared with controls. Both inter- and intraobserver variability were good for all measured parameters, as reflected by intraclass correlation coefficients ( > 0.8) and coefficients of variation ( < 20%). While both E es estimates showed significant differences between DCM patients and controls, one estimate resulted in no overlap and better reproducibility (inter-observer intraclass correlation coefficient: 0.83 vs. 0.47, coefficients of variation: 20 vs. 29%). This is the first study to test the feasibility of using RT3DE-derived LV volumes in conjunction with arterial tonometry to noninvasively quantify LV elastance and Clv-a. This approach was found to be sensitive enough to detect expected differences in LV contractility and reproducible. Due to its noninvasive nature, this methodology may have clinical implications in various disease states. © 2011 the American Physiological Society.
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    Three-dimensional echocardiographic quantitative evaluation of left ventricular diastolic function using analysis of chamber volume and myocardial deformation
    (2013-02-01) Chattanong Yodwut; Roberto M. Lang; Lynn Weinert; Homaa Ahmad; Victor Mor-Avi; University of Chicago Medical Center; Mahidol University
    Currently, no real-time three-dimensional echocardiographic (RT3DE) indices are recommended by the official guidelines for the assessment of diastolic dysfunction (DD). We hypothesized that recent developments in RT3DE imaging technology that allow dynamic quantification of both left ventricular (LV) volume and 3D myocardial deformation, could be utilized to objectively assess DD. Transthoracic RT3DE datasets were acquired (Philips iE33, X5 transducer, frame rate 19 ± 4) in 76 subjects, including 20 normal controls (NL), 16 mild DD, 20 moderate DD and 20 severe DD (grade 1, 2 and 3, respectively, using ASE guideline). Images were analyzed using prototype software (TomTec) that performs 3D speckle tracking to generate time curves of LV volume and segmental myocardial strain. Indices of diastolic LV function were calculated: volume at 25, 50 and 75 % of filling duration (FD) in percent of end-diastolic volume (volume index, LVVi), and rapid filling volume (RFV) fraction. Temporal indices included: FD in % of RR, and rapid filling duration (RFD) in % of FD. Additionally, longitudinal, radial and circumferential strains at 25, 50 and 75 % of FD were calculated. Inter-groups differences were tested using ANOVA. LVVi and RFV fraction showed a biphasic pattern with the severity of DD characterized by an initial decrease (grade 1), a pseudo-normalization (grade 2), and then an increase above normal (grade 3). FD progressively decreased with severity of DD. RFD was significantly increased in all 3 groups compared to NL. After normalization by peak systolic values, all three strain components showed a linear pattern with the severity of DD, suggesting potential clinical usefulness. This is the first study to show that current RT3DE technology allows combined quantitative analysis of LV volume and 3D myocardial strain, which is sensitive enough to demonstrate differences in myocardial relaxation in patients with different degrees of DD. © 2012 Springer Science+Business Media, B.V.