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| Fig.4.27 |
Almost all of the previous comments also apply to the detection and approximate quantification of aortic insufficiency. Aortic regurgitant jets may be small and narrow. When they are, location and mapping by convention PW techniques may be very time-consuming. Color flow approaches can readily identify these abnormalities, as seen in Figure 4.27. This narrow jet occupied only a very small portion of the area of the outflow tract when viewed in short axis (Fig. 4.27, panel B).
 |
| Fig.4.28 |
More typically, a strong turbulent signal is detected and aliasing
occurs. Figure
4.28 demonstrates the resultant mosaic across the entire left
ventricular outflow tract in diastole resulting from aortic insufficiency.
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| Fig.4.29 |
The various directions of flow produced by aortic insufficiency also reveal useful information other than presence or severity alone. In Figure 4.29 an aortic regurgitant jet is directed toward the anterior mitral valve leaflet, then reflected off to the left in a patient with a low-pitched diastolic rumbling murmur suggestive of mitral stenosis. No aortic insufficiency murmur was audible. No mitral stenosis was present by conventional echocardiography or by Doppler. Even though the degree of aortic insufficiency was small, the direction of the jet readily explained the origin of the murmur, as it was likely that the regurgitant jet set the mitral valve into rapid vibrations. This is the classical description of the origin of the Austin-Flint mitral rumble.
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| Fig.4.30 |
| |
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| Fig.4.31 |
Use of the color M-mode is frequently helpful for timing of cardiac events. In Figure 4.30 there is a parasternal long-axis view from a 30-year-old patient who had had mild fevers and two positive blood cultures several months prior to admission with a large and markedly turbulent aortic insufficiency jet direct toward the apex of the left ventricle along the posterior aspect of the interventricular septum. With the M-mode beam directed through the mitral valve, premature closure of the mitral valve apparatus was noted to occur well before the QRS complex, probably as a result of the significant hemodynamic load of the aortic insufficiency (Fig. 4.31). The left ventricular diastolic pressure was high enough to close the mitral valve before the onset of systole. Of note is the fact that most of the mitral regurgitation was seen before mechanical systole began; following the QRS complex, little mitral regurgitation was noted.
2004