| 1. |
- Strotmann, J. M., et al.
(författare)
-
The effect of pacing-induced heart rate variation on longitudinal and circumferential regional myocardial function after acute beta-blockade a cardiac ultrasound study
- 2000
-
Ingår i: European Journal of Echocardiography. - : Oxford University Press (OUP). - 1525-2167 .- 1532-2114. ; 1:3, s. 184-195
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: To evaluate the effect of acute beta-blockade in combination with differing heart rates on longitudinal and circumferential regional myocardial function using Doppler myocardial imaging and two-dimensional-echocardiography. Methods and Results: In seven pigs the following echocardiographic indices were measured at baseline, after beta-blockade both without and with atrial pacing: wall thickening fraction, fractional shortening, myocardial peak systolic velocity, transmyocardial velocity gradient and systolic velocity time integral of the posterolateral wall in short-axis view; mitral valve plane excursion, myocardial peak systolic velocity and systolic velocity time integral of the posterolateral wall in an apical five-chamber view. Peak systolic velocities and velocity gradients decreased significantly following acute beta-blockade but no further decay occurred at high heart rate due to pacing. The velocity time integrals and mitral valve plane excursion showed a tendency to decrease following beta-blockade but only after pacing were they significantly reduced. The wall thickening fraction and fractional shortening showed a significant reduction after beta-blockade but no further decay after pacing. Conclusions: Changes in systolic velocities and velocity gradients were independent of heart rate reduction under high dosage beta-blockade, whereas wall thickening fraction, mitral valve plane excursion and velocity time integrals changed due to pacing.
|
|
| 2. |
- Brodin, L A, et al.
(författare)
-
[Hopeful future for echocardiography. Progress within both the function and perfusion areas].
- 2000
-
Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 97:46, s. 5302-4, 5307
-
Tidskriftsartikel (refereegranskat)abstract
- Echocardiography is presently a feasible method for quantitative estimation of intracardiac flows, pressure levels and for hemodynamic evaluation of valvular disease. The evaluation of regional myocardial function is still based on subjective scrutiny, and no routine method for the estimation of myocardial blood flow is available. We present an overview of newly developed techniques that are beginning to gain purchase in clinical practice. The use of native second harmonic imaging to improve image quality and of tissue Doppler to provide objective measurements of regional myocardial function is discussed. This article describes the transformation of tissue Doppler information into parametric images as in strain rate imaging, and overviews the use of ultrasound contrast agents. Used together with new imaging modalities, myocardial contrast echocardiography holds promise for future quantification of myocardial blood volume and flow. Other emerging echocardiographic technologies discussed are non-invasive measurement of coronary flow reserve and three dimensional cineloop visualization, developed to increase our understanding of cardiovascular physiological and anatomical coupling.
|
|
| 3. |
- Fraser, AG, et al.
(författare)
-
Feasibility and reproducibility of off-line tissue Doppler measurement of regional myocardial function during dobutamine stress echocardiography
- 2003
-
Ingår i: European Journal of Echocardiography. - 1525-2167 .- 1532-2114. ; 4:1, s. 43-53
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: Off-line post-processing of colour tissue Doppler from digital loops may allow objective quantification of dobutamine stress echocardiography. We assessed the reproducibility of off-line measurements of regional myocardial velocities. Methods and Results: Nine observers analysed 10 studies, each making 2400 observations. Coefficients of variation in basal segments from apical windows, at rest and maximal stress, were 9-14% and 11-18% for peak systolic velocity, 16-18% and 17-19% for time-to-peak systolic velocity, 9-17% and 18-24% for systolic velocity time integral, and 18-23% and 21-27% for systolic acceleration. Coefficients of variation for diastolic velocities in basal segments at rest were 11-40%. Coefficients of variation for peak systolic velocity were 10-24% at rest and 14-28% at peak in mid segments, and 19-53% and 29-69% in apical segments. From parasternal windows coefficients of variation for peak systolic velocity were 14-16% in basal posterior, and 19-29% in mid-anterior segments. High variability makes measurement unreliable in apical and basal anterior septal segments. The feasibility of obtaining traces was tested in 92 subjects, and >90% in all basal and mid segments apart from the anterior septum. Conclusion: Quantification of myocardial functional reserve by off-line analysis of colour tissue Doppler acquired during dobutamine stress is feasible and reproducible in 11 segments of the left ventricle. The most reliable measurements are systolic velocities of longitudinal motion in basal segments.
|
|
| 4. |
|
|
| 5. |
- Janerot-Sjöberg, Birgitta, 1958-, et al.
(författare)
-
Effect of contrast on systolic myocardial ultrasound color-Doppler velocity.
- 2001
-
Ingår i: Proceedings to IEEE Engineering Med & Biol(CD skiva),2001. - : IEEE. - 0780372115 ; , s. 3289-3291
-
Konferensbidrag (refereegranskat)abstract
- Intravenously distributed ultrasound contrast increases echoes from the normally low echogenic bloodpool and myocardial perfusion imaging is developing. However the microspheres used are potential endothelial stimulators as well as nonlinear scatterers. Tissue Doppler is developed to detect velocities of myocardial motion, which are in the same range as perfusion flow velocities. The effect of contrast is not evaluated. We performed echocardiography in 12 patients with ischemic heart disease before and immediately after a slow intravenous infusion of 27 ml Optison® using color myocardial Doppler imaging (GE Vingmed systemV). Longitudinal basal systolic velocities and their integrals were analyzed in digitally stored cineloops. Peak mean velocity increased 10% by contrast from mean 5.2 ± 1.8 (SD) to 5.7 ± 2.3 cm/s (p=0.02, confidence interval 2-16%) but integral did not change (0.8 ± 0.4 cm). Contrast has no effect on blood pressure or heart rate in used dose. It is therefore of interest to further evaluate if this increase in velocity; a) is a methodological effect that may be used to detect contrast within myocardium (and thereby perfusion/blood volume), or b) is secondary to increased flow and motion caused by endothelial and vascular effects from the contrast microspheres. Either have important methodological, physiological and clinical impact.
|
|
| 6. |
|
|
