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- 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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| 2. |
- Escobar Kvitting, John-Peder, et al.
(författare)
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Regional asynchrony in acute ischemia and stunning : an experimental myocardial velocity and strain rate imaging study
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To quantify motion and deformation asynchrony using Doppler myocardial imaging (DMI) during acute total ischemia, and stunning of the posterior left ventricular wall (PW) in comparison with the interventricular septum (IVS).Methods: Ischemia of the PW was induced in closed-chest pigs using an angioplasty balloon positioned in the circumflex coronary artery. Animals were divided into three groups: normal controls (Group I - n = 6), total ischemia (Group II - n = 8), and stunning (Group III - n = 6) induced by coronary occlusion with distal coronary perfusion maintained via a perfusion catheter coupled to a roller pump (Group III). In addition, a 2-step dobutamine challenge (5 and 10 µg.kg-1 .min-1) was performed in groups I and III. Doppler myocardial velocity and strain rate cineloops were acquired from a parasternal short axis view.Results: The pre-ejection time (T1) and the duration of regional mechanical systole (SYS) became shorter with inotropic stimulation. During total ischemia T1 was prolonged and SYS shortened significantly compared to baseline values [62 ± 14 vs. 55 ± 13 ms (P < 0.05)], [164 ± 13 vs. 240 ± 27 ms (P < 0.001)], respectively. The fraction T1/SYS was accordingly higher. No changes were observed for the contra lateral non-ischemic wall. In group III, the post-ischemic myocardium had a similar response as non-ischemic myocardium to the dobutamine challenge.Conclusion: Consistent changes in local pre-ejection time and regional mechanical systole are induced by intropic stimulation and by total ischemia. However, the response to intropic stimulation did not differ between normal and stunned myocardium.
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| 3. |
- 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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