| 1. |
- Gunnes, S., et al.
(författare)
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Analysis of the effect of temporal filtering in myocardial tissue velocity imaging
- 2004
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Ingår i: Journal of the American Society of Echocardiography. - : Mosby Inc. - 0894-7317 .- 1097-6795. ; 17:11, s. 1138-1145
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Tidskriftsartikel (refereegranskat)abstract
- Signal filtering to reduce random noise may compromise the reliability of tissue velocity measurements. This study evaluates the influence of temporal filters on time and velocity variables derived from myocardial tissue velocity images acquired in 15 healthy individuals at a high frame rate (142-184 Hz). Different time and velocity variables from the basal septum were analyzed offline before and after temporal filtering from 20 to 60 milliseconds in 10-millisecond steps using software enabling retrieval of myocardial Doppler velocity and 2-dimensional information from different cardiac locations during the same cardiac cycle. Filtering affected the results by increasing variability of time and by underestimation of velocity variables, the rapid isovolumic events being particularly filter sensitive. In addition, at a certain range of sampling rate, ambiguity of filtering effect was observed. This ought to be considered if an optimal, high-fidelity tissue Doppler velocity signal is to be obtained.
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| 2. |
- Hayashi, Shirley Yumi, et al.
(författare)
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Improvement of cardiac function after haemodialysis : Quantitative evaluation by colour tissue velocity imaging
- 2004
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Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 19:6, s. 1497-1506
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Tidskriftsartikel (refereegranskat)abstract
- Background. Overhydration and accumulation of uraemic toxins may influence the myocardial function in haemodialysis (HD) patients. To evaluate cardiac function and the effects of fluid and solute removal during a single session of HD, colour tissue velocity imaging (TVI) was used. This new technique, which is less load dependent than conventional echocardiography, allows an objective quantitative assessment of myocardial contractility, contraction and relaxation. Methods. Conventional echocardiographic and TVI images were recorded before and after a single HD session in 13 clinically stable HD patients (62 +/- 10 years, six males) and in 13 sex- and age-matched healthy controls. Myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVC), peak systole (PS), early (E) and late (A') diastolic filling and strain rate (SR) were measured. Results. Left ventricular hypertrophy (LVH) was present in 12 patients. TVI gave additional information in comparison with conventional echocardiography. Before HD, PS (5.0 +/- 0.8 vs 6.0 +/- 1.2 cm/s, P < 0.05), E' (5.7 +/- 1.7 vs 7.3 +/- 2.0 cm/s, P < 0.05) and A' (6.6 +/- 1.7 vs. 8.3 +/- 2.9 cm/s, P < 0.05) velocities were lower in the patients than in the controls, indicating systolic and diastolic dysfunction. The HD session increased IVCv (4.0 +/- 1.7 to 5.5 +/- 1.9 cm/s; P < 0.001), PSv (5.0 +/- 0.8 to 5.7 +/- 0.8 cm/s; P < 0.05) and SR (0.7 +/- 0.2 to 0.9 +/- 0.2 1/s; P < 0.05) and decreased E/E' (16.7 +/- 7.7 to 12.2 +/- 4.0, P < 0.05), indicating improved systolic function and decreased LV filling pressure, respectively. Linear regression analysis demonstrated a dependency of systolic contraction (PSv) and contractility (IVCv) upon plasma levels of phosphate (r(2) = 0.70, P < 0.005, r(2) = 0.33, P < 0.01). Conclusions. Using TVI, HD patients demonstrate myocardial dysfunction, which is found less frequently when using conventional echocardiography. The systolic function seems to be impaired by high plasma levels of phosphate and an increased Ca x P product. One single session of HD improved systolic function as indicated by increases in IVCv, PSv and SR. Further studies are needed to clarify if this effect of HD is due to the acute removal of fluid, the removal of solutes or both.
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| 3. |
- Lind, Britta, et al.
(författare)
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Left ventricular isovolumic velocity and duration variables calculated from colour-coded myocardial velocity images in normal individuals
- 2004
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Ingår i: European Journal of Echocardiography. - : Oxford University Press (OUP). - 1525-2167 .- 1532-2114. ; 5:4, s. 284-293
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To describe the normal myocardial velocity profile during the isovolumic contraction and relaxation period at four different locations within left ventricular base and to establish normal age and gender related isovolumic time and velocity values. Methods and results: In 49 healthy individuals (26 women/23 men) in age groups 21-49 and 50-76 years, tissue velocity profiles and 2D-data were acquired at high temporal resolution (90-147 frames/s) for a subsequent off-line analysis using software enabling retrieval of myocardial Doppler velocity and 2D/anatomical M-mode information from different cardiac locations during the same cardiac cycle. The obtained velocity curves during the isovolumic contraction and relaxation period were usually biphasic and displayed clear regional differences in their respective positive and negative maximal velocities. Besides some gender related differences, mainly in the duration of the positive and negative velocity wave components during the isovolumic contraction period, a clear age-dependent increase in the duration of the isovolumic relaxation phase and its negative and positive velocity components was observed. Conclusion: Modern tissue Doppler imaging supplemented by anatomical M-mode images of the mitral and aortic valve movements allows a proper analysis of the rapid isovolumic myocardial movements. The presented normal isovolumic time and velocity values may prove useful for studies of myocardial function.
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| 4. |
- Quintana, M., et al.
(författare)
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Assessment of the longitudinal and circumferential left ventricular function at rest and during exercise in healthy elderly individuals by tissue-Doppler echocardiography : relationship with heart rate
- 2004
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Ingår i: Clinical Science. - : Portland Press Ltd.. - 0143-5221 .- 1470-8736. ; 106:5, s. 451-457
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Tidskriftsartikel (refereegranskat)abstract
- Tissue-Doppler echocardiography (TDE) has been introduced to quantify stress echocardiography by means of assessing the left ventricular (LV) segmental myocardial velocities and excursion. The interaction between LV long- and short-axis function during physical exercise has not been elucidated completely. The aim of the present study was to investigate long- and short-axis LV function, as assessed by myocardial velocities and excursions at rest and during exercise and its possible relationship with heart rate in healthy elderly individuals by TIDE Twenty-seven individuals underwent an exercise test in the supine position on a bicycle ergometer. The initial workload was 30 Watts, followed by 20-Watt increments every third minute. Standard echocardiographic images with super-imposed colour TDE were digitized at the end of each step. The following variables were studied in the LV long- and short-axis: myocardial peak systolic velocity (PSV) and excursion, isovolumic contraction and relaxation times, peak velocity at early diastole (E-wave) and peak velocity at late diastole (A'-wave) and the E'/A' ratio. Increments in myocardial peak systolic velocity and excursion in the LV long-axis were more pronounced during low workloads. The increase in those variables in the short-axis occurred mainly, at higher exercise loads. The improvement in LV long- and short-axis functions was closely related to the increase in the heart rate. Shortening of the isovolumic contraction and relaxation times occurred only at the initial stages of exercise. An increase in the long-axis E'/A' ratio occurred during exercise, whereas this ratio was unchanged in the short-axis. In conclusion, during exercise, the LV long- and short-axis functions behave differently, and increases in LV long- and short-axis functions are related to changes in heart rate. Therefore, in the interpretation of echocardiographic findings during exercise stress echocardiography, these facts have to be taken into account.
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| 5. |
- Quintana, M., et al.
(författare)
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Electromechanical coupling, uncoupling, and ventricular function in patients with bundle branch block : A tissue-doppler echocardiographic study
- 2004
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Ingår i: Echocardiography. - : Wiley. - 0742-2822 .- 1540-8175. ; 21:8, s. 687-698
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Tidskriftsartikel (refereegranskat)abstract
- Background: Left bundle branch block (LBBB) is associated with impaired left ventricular (LV) function and increased morbidity and mortality, especially in patients with structural heart diseases. The mechanisms are poorly understood. Subjects and Methods: Subjects with isolated LBBB (n = 20), right bundle branch block (RBBB, n = 20), and controls (C, n = 20) were studied with standard two-dimentional (2D), and color-encoded tissue-Doppler echocardiography (TDE). Inter- and intraventricular systolic and diastolic coordination were assessed from the TDE velocity profiles. LV function was assessed by 2D echocardiography, by TDE-derived peak systolic velocities, and the atrioventricular (AV) plane displacement. Results: Subjects with LBBB had longer electromechanical delays and longer isovolumic relaxation times than did the C and RBBB groups (P < 0.001). For the LBBB subjects compared with the RBBB and C groups, ejection times were shorter, peak systolic velocities and AV plane displacements were lower, they had larger LV end-systolic volumes and lower LV ejection fraction (all P < 0.001), and the atrial contribution to A-V plane displacement was higher (P < 0.01). There were no differences in diastolic or filling times among the groups. Conclusions: In patients with LBBB, delayed regional electromechanical coupling and uncoupling leads to generalized intra- and interventricular asynchrony, thereby explaining the depressed regional and global LV functions. Assessment of the electromechanical coupling and uncoupling processes and their consequences on cardiac function in patients with BBB and structural heart diseases may be possible using TDE.
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| 6. |
- Saha, S. K., et al.
(författare)
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Myocardial velocities measured during adenosine, dobutamine and supine bicycle exercise : a tissue Doppler study in healthy volunteers
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 24:5, s. 281-288
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dobutamine stress echocardiography (DSE) quantified by tissue Doppler (TVI) have improved the diagnostic capacity of the procedure. Quantification of other stress modalities, e.g. adenosine stress echo (ASE) and exercise stress echocardiography (ESE) are necessary for assessing any pathophysiological differences in different forms of stress. Methods: Ten healthy individuals underwent ASE, DSE, and ESE during a span of 2-5 days. Left ventricular (LV) apical images at rest and peak stress (max) were postprocessed using TVI on a GE System FiVe equipment. ECG-derived QRS duration (QRSD, ms), heart rate (HR, bpm), TVI-estimated basal systolic velocities (S2V, cm s(-1)), ejection time (S2T, ms) and strain (S, %) were computed off-line and compared. Longitudinal displacement imaging, tissue tracking, was also made. Results: Data for ASE, DSE and ESE during peak stress were (HR: 84 +/- 12***, 142 +/- 19, 137 +/- 27; P0.05) response at a much lower HR indicates that adenosine has minor effects on contraction presumably secondary to vasodilatation. Powerful chronotropic response to DSE and ESE is probably prerequisite for strong velocity response at the expense of strain and displacement. TVI-assisted stress echocardiography thereby shows different LV systolic response in healthy individuals, depending on stress modality.
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| 7. |
- Storaa, C., et al.
(författare)
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Distribution of left ventricular longitudinal peak systolic strain and impact of low frame rate
- 2004
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Ingår i: Ultrasound in Medicine and Biology. - : Elsevier BV. - 0301-5629 .- 1879-291X. ; 30:8, s. 1049-1055
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Tidskriftsartikel (refereegranskat)abstract
- The myocardium has complex 3-D motion that is frequently described using ultrasound (US) Doppler techniques that are limited to recording velocities in one dimension only. Studies using 3-D tagged magnetic resonance show that the myocardium has strain components with varying angles throughout the myocardium. Despite this, there seems to be a belief that the left ventricular longitudinal strain distribution should be homogeneous. When measuring myocardial strain, there are several parameters for the clinician to decide on, one of them being recording frame rate. The current study aims to further investigate the alleged homogeneity of the longitudinal myocardial strain distribution and to discover the impact that the frame rate has on these measurements. Myocardial strain was measured in 43 healthy individuals at different frame rates. Analysis of variance results clearly demonstrate that the strain is not uniformly distributed over the wall; there seems to be an increasing strain from apex toward the base. However, subjects exist with different distributions; thus, it is not possible to conclude that certain strain patterns are normal. Reduced frame rate had a highly significant impact on the measured strain results and it is seen that, at low frame rates, the strain values were reduced. (E-mail: Camilia.Storaa@labmed.ki.se)
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| 8. |
- Storaa, Camilla, et al.
(författare)
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Tissue motion imaging of the left ventricle--quantification of myocardial strain, velocity, acceleration and displacement in a single image
- 2004
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Ingår i: European Journal of Echocardiography. - : Oxford University Press (OUP). - 1525-2167 .- 1532-2114. ; 5:5, s. 375-385
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Several methods of parametric imaging of left ventricular function including tissue velocity imaging (TVI) and strain rate imaging (SRI) have previously been presented, however, they have the limitation that they can, respectively, portray only one physiological myocardial parameter. The aims of this pilot study were to implement and validate tissue motion imaging (TMI) for the first time, a visualization technique which permits acceleration, velocity, displacement and strain to be interpreted quantitatively or semi-quantitatively in a single image. METHODS AND RESULTS: TMI is achieved by the color coding of temporal tissue velocity integrals. The principles behind this technique are validated, and case examples demonstrating its use in the clinical setting are provided. Limitations of the method as well as future applications and improvements are discussed. CONCLUSION: As this method allows representation of a multitude of variables and is visually attractive, it may facilitate more widespread use of myocardial quantitation in everyday practice.
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| 9. |
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