Echocardiographie clinique du chien et du chat: Techniques et applications pratiques (French Edition)
These leaks usually occur at the level of the mitral valve. What is known as physiological MR is observed in more than one in two cases in young, healthy volunteers.
In contrast, the presence of a physiological aortic leak is exceptional. They are also more common in athletes as a result of the modification of the heart geometry. Pitfalls when diagnosing mitral valve prolapse TTE is a determining examination in the diagnosis of MVP, the most common valvulopathy in the population.
Pitfalls of M-mode echocardiography Monodimensional M-mode echocardiography provides the classical and historical criteria for MVP, which are Figs 6. The most specific picture of a prolapse is the end-systolic cup shape. M-mode echocardiography is unreliable in diagnosing MVP as it describes mitral movements in relation to a fixed point the thoracic wall. A false appearance of a prolapse may thus arise when the whole of the mitral apparatus moves away from the probe without any genuine move- 53 54 Cardiac valves Diastole Systole Diastole Systole a b Figure 6.
In reality, M-mode echocardiography gives rise to numerous false-negative and false-positive diagnoses of MVP. Moreover, it does not allow exact identification of the prolapsed valve or assessment of the degree of systolic recoil in the LA. Failure to recognize the prolapse of the lateral scallops of the small mitral valve.
In fact, only the median scallop of the small valve is identifiable in M-mode echocardiography when using the traditional projection.
Poor image specificity of the hammock-shaped prolapse. A falsely hammockshaped MVP can be observed in a number of situations Box 6. Pitfalls of two-dimensional echocardiography Two-dimensional echocardiography occupies a primary position in the diagnosis of MVP. Abundant pericardial effusion During ventricular extrasystoles Under administration of pharmacodynamic agents glyceryl trinitrate, amyl nitrate, etc. During a Valsalva manoeuvre echocardiography cannot do so.
Nonetheless, this technology can be responsible for false diagnoses of prolapse as a result of the following pitfalls Box 6. Looking for a prolapse in an apical cross-section is responsible for a large number of false-positive diagnoses, and this has led to an overestimation of the frequency of the condition.
In fact, an image of an MVP can be artificially induced in this view by using an excessively large angle between the ultrasound beam and the atrioventricular plane Fig. Moreover, the defined saddle shape of the mitral annulus parabolic hyperbole can be responsible for a false appearance of a prolapse in the apical view in a normal subject. For these reasons, the echocardiographic diagnosis of MVP should be carried out using the longitudinal parasternal cross-section, which is considered to be the most reliable reference view Fig.
Failure to observe the rules for imaging a prolapse in the 2D mode When studying a prolapse using 2D echocardiography in real time, it is necessary to beware of the misleading appearance of the image in movement. The diagnosis of MVP should be made using a frozen image, and preferably using the zoom and cine mode. Next, a virtual line is traced at the level of the mitral annulus the reference point for the prolapse. This technique rests on an implicit hypothesis: i. However, it is possible to create an appearance of a prolapse in the apical cross-section without seeing the prolapse in the longitudinal cross-section perpendicular to it.
This discrepancy occurs when the mitral annulus is saddle shaped, i. These are the points visualized in the longitudinal, parasternal cross-section. A systolic valvular movement visualized only in the apical cross-section is, therefore, the consequence of a normal valve geometry, without actual displacement of the mitral valves above the structure of the mitral annulus. The three-dimensional reconstruction of the mitral valve validates this geometric hypothesis Fig. However, the correct definition of the plane of the mitral annulus may be difficult in the long axis, parasternal projection, as the mitral annulus, which is particularly hyperkinetic, may move during systole towards the LV.
Figure 6. The degree of valvular movement is assessed by the recoil of the systolic coaptation point of the mitral valves in relation to the plane of the mitral annulus.
Failure to observe the echocardiographic criteria for a diagnosis of prolapse, which have been recently redefined, may lead to an incorrect or mistaken diagnosis of an MVP. Imprecision in locating a mitral valve prolapse Two-dimensional echocardiography makes it possible directly to identify the prolapsed valve, and to specify the location and extent of the prolapse. This information is particularly useful in assessing the patient for potential conservative surgery. In order to avoid these pitfalls, a complete anatomical and functional analysis of the whole of the mitral apparatus is necessary.
This should be carried out systematically transthoracically, with the transoesophageal route recommended Table 6. A standardized segmentation of the mitral valve facilitates a precise description of the valvular lesions. Use of multiple echocardiographic projections allows for an exploration of all the mitral segments and the commissures see Fig. However, comparison of the echocardiographic images with anatomical data reveals certain differences regarding the location of the prolapse.
In fact, 2D echocardiography may show a prolapse of both mitral valves, despite degenerative anatomical lesions affecting only one valve. The mitral leaflets come together during ventricular systole, and therefore the prolapse of one valve encourages the recoil of the other.
Incomplete appreciation of mitral valve thickening Abnormal mitral valve thickening is a reflection of the myxomatous infiltration of the spongy layer of the mitral valve. A thorough study of the whole of the mitral valve apparatus from various views is necessary in order to confirm the dystrophic injury.
During diastole, the large mitral valve, which is flaccid and distended as a result of the dystrophy, undergoes a characteristic deformation into the shape of a helmet. Sometimes, the myxomatous thickening of the mitral valve is such that they appear on the image to be vegetations or even a myxoma. The chordae can be lengthened and thinned or, more often, thickened.
A rupture of the chordae is also possible. The mitral annulus is more or less dilated. However, in these particular dystrophic forms, there is no abnormal valve thickening; rather, the mitral valves are fine and transparent Box 6. Failure to identify ruptured chordae The echocardiographic identification of ruptured chordae associated with MVP is a function of the number and the location on the valves of the ruptures.
PRATIQUES CLINIQUE DES GREFFES OSSEUSES ET IMPLANTS PDF
The rupture generally involves the chordae of the small mitral valve. A positive diagnosis of ruptured chordae rests on examination using 2D echocardiography. Moreover, elongations and ruptures of the chordae can coexist in the same patient. The direct visualization of a piece of ruptured chorda attached to the valve and flail in the ventricular chamber is rare but possible, particularly in TEE. This image should not be confused with a valvular vegetation.
Clinical ecocardiography of dog and cat; mADRON, CHETBOUL & BUSSAD
It is difficult to detect ruptures to the principal basal and paracommissural chordae when using TTE. However, such ruptures can be detected markedly better using multiplanar TEE. This type of MVP is a semiological epiphenomenon in the evolution of these conditions. Pitfalls when diagnosing infective endocarditis Echocardiography plays a fundamental role in diagnosing infective endocarditis, as it provides major diagnostic elements. The pitfalls associated with the echocardiographic imaging of endocarditis principally concern the visualization of valvular vegetations and the detection of destructive lesions.
In all cases the interpretation of the echocardiographic images must take into account the clinical context. Diagnostic pitfalls due to endocardial vegetations Classically, the diagnosis of vegetations rests on the detection with 2D echocardiography of a mass of abnormal echoes appended to the valve or to an endocardial structure that is round or oblong, more or less mobile or even pedunculated, and brighter than the adjacent tissue Figs 6.
The pitfalls of echocardiographic imaging, particularly in the transthoracic projection, in making a positive diagnosis of vegetations are as follows. Valvular vegetations with a thickness Pitfalls when diagnosing the aetiology of valvular leaks relation to the clinical presentation.
Ubuy Kuwait Online Shopping For locatelli in Affordable Prices.
This is a frequent cause of false-negative results Box 6. Therefore, when there is a strong diagnostic reason to suspect endocarditis, it is necessary to repeat the examination if the echocardiographic result is negative. Distinction between a vegetation and other valvular lesions The echocardiographic distinction between a vegetation and other valvular lesions is sometimes difficult, or even impossible. Questionable echocardiographic images, suggesting a vegetation, may be observed in a patient with suspected endocarditis. The most common causes of orientation errors false-positive results are summarized in Box 6.
- The Creation Mythology Photo Book.
- The Complete Mystery of Matthew Alcott: HERITAGE OF SECRETS.
- Revue des Maladies Respiratoires - Présentation - EM consulte;
- Regiment Kaiser Alexander bei Faverolles: Anfang Juni 1918 (German Edition).
They arise in particular when, due to underlying cardiac pathology, the valves are thickened, fibrosed, calcified or myxomatous. The difficulty in achieving a diagnosis of endocarditis arises, in particular, in patients presenting with a dystrophic condition of the mitral valve when there is also an associated rupture of the chordae. In all these pathological situations, the differential diagnosis is made by referring to the clinical context. However, if there is the slightest doubt, there should be no hesitation in repeating the echocardiographic examination, and all the more so if the clinical profile is highly suggestive of endocarditis.
TEE can make a useful contribution in these cases. Distinction between an active vegetation and a sterile or treated vegetation Distinguishing echocardiographically between a bacteriologically active vegetation and a sterile or treated vegetation is impossible. Likewise, no correlation has been found between the echocardiographic appearance of vegetations and Box 6. Non-inflammatory aetiology of vegetations Generally, vegetations are of bacterial origin and are due to inflammation of the endocardium. The presence of non-infective vegetations has been noted in Libman—Sack endocarditis or marastic endocarditis.
This type of vegetation can also cause false-positive echocardiographic results.