We all love criteria, checklists, and guidelines. They help us to remember and deal with complex issues. However, in very complex and variable situations it may be better to rely on “the recognition of patterns” and look at several examples.
A Russian emergency
To illustrate this, let us start with a case from Liza, one of our Facebook friends from Russia:


Liza Kononova works in an emergency hospital in Tver -
a Russian city located north of Moscow
at the confluence of the Volga and Tvertsa rivers.

A 64 year-old women with a history of hypertension was brought to the emergency department with pulmonary edema. Here is her echo:

Four-chamber view. Hyperdynamic left ventricular function
and something else?

Can you tell what is wrong? It is certainly not poor left ventricular function that is causing her problems. It is more likely a mitral valve pathology. The next picture might give you a better idea.

Note that a small portion of the mitral valve has ruptured

You have to look very carefully to see that a small portion of the mitral valve is dangling below the mitral valve. This is called a partial flail leaflet. It is sometimes quite difficult to determine which leaflet is flail - especially when the problem is in the commissural region. Usually the direction of the jet will tell you. In the case of a flail anterior leaflet the jet will be directed in posterior and lateral direction. If the posterior leaflet is flail the jet will be directed in anterior and medial direction. In this case it was a posterior flail leaflet.
Ready for more examples?
While the cause of her pulmonary edema is clear (acute mitral regurgitation with volume overload), establishing the diagnosis of a partial flail leaflet can be tricky, especially because the appearance of this pathology may differ widely from person to person. I want to show you a few other examples so you can recognize some of the patterns of a partial flail leaflet. This one is quite similar to that provided by Liza.

The “parallel” sign in partial flail leaflets

Note that I am using the zoom function to display the small portion of the anterior leaflet that is flail. The zoom function increases spatial as well as temporal resolution of the image. Thus, it is easier to observe the fine fibrillating motion of the ruptured tissue. One of the key features in most cases of a flail leaflet is that the ruptured portion of the valve extends below the other leaflet. This happens because the ruptured part of the leaflet is now longer. I call this sign the “parallel” sign because the non-affected (other) leaflet is parallel to the ruptured chordae.
Easy example…
The next case is fairly easy - not only because the image is of good quality, but also because the flail chord is rather long.

A rather long chord is detached

Remember: rupture may occur at different sites of the subvalvular apparatus - either close to the valve (as in the two previous cases) or closer to the papillary muscle (as shown here). If the flail chord is long you may find it assuming a concave position with respect to the left atrium.
Who needs color Doppler?
Let us observe the direction of the MR jet in this patient.

Eccentric jet in a patient with posterior flail leaflet

The direction of the jet was no surprise. It is directed medially. If you go back to the 2D image you can sense the direction of the jet. Blood flows through a channel which is formed between  the anterior  leaflet and the posterior flail leaflet (parallel sign), One does not even need color Doppler to discover the direction of the jet.
… and a difficult one
In some cases it is impossible to detect a flail leaflet with transthoracic echo. This is when TEE becomes important. Here is an example:

TEE study: subtle form of a flail leaflet.

Look how subtle the defect is. Again, a very small portion of the posterior leaflet is flail. To find the exact spot one must scan all portions of the valve (both in TTE and TEE). In these cases color Doppler will help to find the exact region of the defect. How severe do you think regurgitation is in this case?

Well, it is very severe. The lesson here is: the magnitude of the morphologic findings on 2D does not always correlate with the severity of regurgitation.
A sequel of aging
The next example is that of a patient in whom not only a chord, but also a small portion of a papillary muscle was ruptured.

This patient did not have a myocardial infarction, so this is NOT ischemic papillary muscle rupture. It was an elderly man with significant degenerative abnormalities of the mitral valve (annular calcification and papillary muscle fibrosis). Can you see how the chord with part of the papillary muscle attached swings back and forth between the ventricle and the left atrium?

Note that no regional wall motion abnormalities are present. Also note the hyperdynamic nature of his left ventricular function. As in Liza's case, the patient developed pulmonary edema (acute MRI).
Mitral valve prolapse and flail leaflets
Patients with myxomatous mitral valves are at high risk for chordal rupture. But remember: flail leaflets look quite different in patients with myxomatous mitral valves. The ruptured portions of the valve tend to be thick and bulky. Sometimes one can see a small stalk at the end, indicating the chord that was attached. Does the following patient have a flail leaflet?

Only prolapse of the posterior leaflet

I would say no. Don’t confuse prolapse with a flail leaflet. The main portion of the posterior leaflet shows a prolapse, but because the prolapse is severe it also protrudes below the anterior leaflet. Yet, the tip of the leaflet is bent towards the left ventricle. This is a sign of preserved chordal attachment.
Same pathology, different finding
Now look at the following patient who also has mitral valve prolapse.

Bileaflet prolapse and a flail leaflet

This patient has (bileaflet) mitral valve prolapse AND a flail posterior leaflet. There was a second (more echogenic) structure below the posterior leaflet with a small short chordal structure attached to it (stalk). How do we explain the fact that the posterior leaflet is ruptured, yet the ruptured portion of the valve parallels the posterior leaflet?
If you have performed a 3D study you will know why. The ruptured portion of the mitral valve simply overlaps the still intact but myxomatous portions of the same leaflet. After all, patients with mitral valve prolapse may have a large quantity of excess tissue.
Why the recognition of patterns helps
Do you see how diverse the appearance of a flail leaflet can be? They all look different. Trying to establish the diagnosis simply by memorizing a table in a textbook with a list of criteria will not work. What you need is cases and more cases. As a matter of fact, this is our general approach to teaching. That's why we have thousands of images and videos on our site. So visit us and see what we have to offer.

Thomas & Liza
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