| 1. |
- Winter, Reidar, et al.
(författare)
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Feasibility of noninvasive transthoracic echocardiography/Doppler measurement of coronary flow reserve in left anterior descending coronary artery in patients with acute coronary syndrome: A new technique tested in clinical practice
- 2003
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Ingår i: Journal of the American Society of Echocardiography. - 1097-6795. ; 16:5, s. 464-468
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study was to test the feasibility and accuracy of transthoracic Doppler echocardiography measurement of coronary flow reserve (CFR) in the left anterior descending coronary artery (LAD) territory in the clinical setting of the acute coronary syndrome. Methods: Transthoracic Doppler echocardiography measurements of CFR were made in 42 consecutive patients in the distal LAD before and during adenosine infusion. The results were validated by coronary angiography. A normal CFR was predefined as a more than 2-fold increase of flow velocity during adenosine infusion. Results. We were able to detect significant stenosis in the LAD territory with 92% sensitivity and 82% specificity if we considered a stenosis greater than or equal to 50% to be significant. Defining a stenosis of greater than or equal to 70% as significant increased the sensitivity and the negative-predictive value to 100%, with a specificity of 70%. Conclusion: Measuring CFR using transthoracic Doppler echocardiography is noninvasive, feasible, accurate, and relatively inexpensive. The excellent negative-predictive value of this technique makes it a useful tool for identifying patients who can avoid repeated angiography as a result of suspected subacute LAD restenosis after percutaneous coronary intervention.
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| 2. |
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| 3. |
- Bech-Hanssen, O., et al.
(författare)
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Net Pressure Gradients in Aortic Prosthetic Valves can be Estimated by Doppler
- 2003
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 16:8, s. 858-866
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Tidskriftsartikel (refereegranskat)abstract
- Background: In aortic prosthetic valves, both the Doppler-estimated gradients and orifice areas are misleading in the assessment of hemodynamic performance. The parameter of major interest is the net pressure gradient after pressure recovery (PR). We, therefore, investigated, in vitro, our ability to predict the net pressure gradient and applied the formulas in a representative patient population with 2 different valve designs. Methods: We studied the St Jude Medical (SJM) standard valve (size 19-27) and SJM Biocor (size 21-27) in an in vitro steady-flow model with simultaneous Doppler-estimated pressure and catheter pressure measurements. Using echocardiography, we also studied patients who received the SJM (n = 66) and SJM Biocor (n = 45). Results: In the SJM, we observed PR both within the prosthesis and aorta, whereas in the SJM Biocor, PR was only present in the aorta. We estimated the PR within the valve and within the aorta separately from echocardiographic in vitro data, combining a regression equation (valve) with an equation on the basis of fluid mechanics theory (aorta). The difference between estimated and catheter-obtained net gradients (mean ± SD) was 0.6 ± 1.6 mm Hg in the SJM and - 0.2 ± 1.9 mm Hg in the SJM Biocor. When these equations were applied in vivo, we found that PR had an overall value of 57 ± 7% of the peak Doppler gradient in the SJM and 33 ± 9% in the SJM Biocor. Conclusions: The in vitro results indicate that it is possible to predict the net pressure gradient by Doppler in bileaflet and stented biologic valves. Our data indicate that important PR is also present in stented biologic valves.
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| 4. |
- Castor, S, et al.
(författare)
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Assessment of fetal pulmonic stenosis by ultrasonography
- 1996
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Ingår i: Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography. - : Elsevier BV. - 0894-7317. ; 9:6, s. 805-13
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Tidskriftsartikel (refereegranskat)
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| 5. |
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| 6. |
- Escobar Kvitting, John-Peder, 1976-, et al.
(författare)
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How accurate is visual assessment of synchronicity in myocardial motion? An in vitro study with computer-simulated regional delay in myocardial motion : clinical implications for rest and stress echocardiography studies
- 1999
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 12:9, s. 698-705
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Tidskriftsartikel (refereegranskat)abstract
- Asynchronicity in echocardiographic images is normally assessed visually. No prior quantitative studies have determined the limitations of this approach. To quantify visual recognition of myocardial asynchronicity in echocardiographic images, computer-simulated delay phantom loops were generated from a 3.3 MHz digital image data from a normal left ventricular short-axis heart cycle acquired at 55 frames per second. Six expert observers visually assessed 30 abnormal and 3 normal loops with differing computer-induced delay patterns on 3 occasions and in this optimally simulated environment could recognize only single delays of 89 ms or more. This was improved to 71 ms or more by use of side-by-side (normal versus abnormal) comparative review. Thus visual assessment of clinically important regional delay in rest or stress echo images is limited.
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| 7. |
- Flachskampf, Frank A, et al.
(författare)
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Overestimation of flow velocity through leaks in mechanical valve prostheses and through small orifices by continuous-wave Doppler.
- 1997
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 10:9, s. 904-914
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Tidskriftsartikel (refereegranskat)abstract
- The reliability of continuous-wave Doppler flow velocity measurements through small regurgitant lesions, such as in prosthetic leakage, has not been systematically analyzed. To evaluate the accuracy of continuous-wave Doppler in prosthetic valve leakage and small orifices in an in vitro, steady-flow model-flow velocities through the leaks of twelve intact mechanical prostheses and through six circular nozzles (area 0.5 to 20 mm2) were measured at pressure drops between 30 and 105 mm Hg. These results were compared with those predicted by the modified Bernoulli equation. Laser Doppler anemometry of flow velocities through the nozzles was also performed. Despite high correlation, there was substantial overestimation of Bernoulli predicted velocities by echo Doppler in the prosthetic leaks (mean +12.3% +/- 9.4%; range 90.3% to 143.4%). In the nozzles < or = 10 mm2, but not in the largest (20 mm2) nozzle, there was also overestimation of the Bernoulli predicted velocities (mean +6.2% +/- 2%). Laser Doppler anemometry of flow velocities through the nozzles showed slightly lower values than predicted by the Bernoulli equation. Thus, continuous-wave echo Doppler overestimates flow velocities through small orifices. This apparently is, at least in part, due to transit time effects and should be taken into account when using echo Doppler in small (< 10 mm2) orifices, such as in mild to moderate regurgitant lesions and prosthetic valve leakage.
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| 8. |
- Fyrenius, Anna, et al.
(författare)
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Pitfalls in Doppler evaluation of diastolic function : insights from 3-dimensional magnetic resonance imaging
- 1999
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Ingår i: Journal of the American Society of Echocardiography. - Amsterdam : Elsevier Science B.V.. - 0894-7317 .- 1097-6795. ; 12:10, s. 817-826
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasound-Doppler assessment of diastolic function is subject to velocity errors caused by angle sensitivity and a fixed location of the sample volume. We used 3-dimensional phase contrast magnetic resonance imaging (MRI) to evaluate these errors in 10 patients with hypertension and in 10 healthy volunteers. The single (Doppler) and triple (MRI) component velocity was measured at early (E) and late (A) inflow along Doppler-like sample lines or 3-dimensional particle traces generated from the MRI data. Doppler measurements underestimated MRI velocities by 9.4% ± 8.6%; the effect on the E/A ratio was larger and more variable. Measuring early and late diastolic inflows from a single line demonstrated the error caused by their 3-dimensional spatial offset. Both errors were minimized by calculating the E/A ratio from maximal E and A values without constraint to a single line. Alignment and spatial offset are important sources of error in Doppler diastolic parameters. Improved accuracy may be achieved with the use of maximal E and A velocities from wherever they occur in the left ventricle.
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| 9. |
- Hedberg, Pär, et al.
(författare)
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Mitral annulus motion compared with wall motion scoring index in the assessment of left ventricular ejection fraction
- 2003
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 16:6, s. 622-629
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Tidskriftsartikel (refereegranskat)abstract
- The biplane disc summation method is the recommended echocardiographic procedure to determine left ventricular (LV) ejection fraction (EF). Assessment of mitral annulus motion (MAM) or wall motion scoring index (WMI) has been reported to be less dependent on image quality compared with the recommended method, and proposed as a surrogate to the disc summation method in calculation of LVEF. We aimed to compare MAM and WMI in the echocardiographic assessment of LVEF. In a randomly selected population-based sample of 75-year-old men and women in sinus rhythm (n = 409) MAM, as measured by M-mode, was compared with WMI, calculated as the mean value of wall motion scoring in 9 LV segments. LVEF, as measured by the biplane disc summation method was used as reference. The limits of agreement (mean difference ± 1.96 SD) between LVEF and corresponding MAM values were −18 to +13 LVEF%, and between LVEF and corresponding WMI values were −12 to +13 LVEF%. The areas under the receiver operating characteristic curves for MAM and WMI to predict a LVEF < 50% were 0.892 and 0.998, respectively (95% confidence interval of the difference 0.062-0.149). The corresponding areas for MAM and WMI to predict a LVEF < 40% were 0.955 and 0.998, respectively (95% confidence interval of the difference 0.017-0.069). In conclusion, the ability of WMI to estimate LVEF was more favorable than MAM in this population-based sample of 75-year-old participants. The findings suggest that the WMI is preferable to MAM in estimating LVEF.
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| 10. |
- Strotmann, Jörg M., et al.
(författare)
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Anatomic M-mode echocardiography : a new approach to assess regional myocardial function - A comparative in vivo and in vitro study of both fundamental and second harmonic imaging modes
- 1999
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 12:5, s. 300-307
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the accuracy of anatomic M-mode echocardiography (AMM).Methods: Eight phantoms were rotated on a device at different insonation depths (IDs) in a water beaker. They were insonated with different transducer frequencies in fundamental imaging (FI) and second harmonic imaging (SHI), and the diameters were assessed with conventional M-mode echocardiography (CMM) and AMM with the applied angle correction (AC) after rotation. In addition, left ventricular wall dimensions were measured with CMM and AMM in FI and SHI in 10 volunteers.Results: AC had the greatest effect on the measurement error in AMM followed by ID (AC: R2 = 0.295, ID: R2 = 0.268; P < .0001). SHI improved the accuracy, and a difference no longer existed between CMM and AMM with an AC up to 60 degrees. In vivo the limit of agreement between AMM and CMM was -1.7 to +1.8 mm in SHI.Conclusion: Within its limitations (AC < 60 degrees; ID < 20 cm), AMM could be a robust tool in clinical practice.
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