| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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