So far we have discussed what mitral valve prolapse is, and what causes it. If you have not read the previous sections yet, then I suggest you go read those first to have a basic understanding of the mitral valve. Now we will discuss one of the complications of mitral valve prolapse that is a leaky mitral valve, referred to as mitral regurgitation. Mitral regurgitation is very common; in fact it’s the most common valvular disease in the US, and mitral valve prolapse is the most common cause.
Everytime the main chamber of the heart beats, it ejects blood forward in to the body so it can supply the body with the blood that it needs. The mitral valve is there to prevent blood flowing backwards. So when the valve is defective, blood is allowed to leak backwards. The amount of leak (regurgitation) can range from being very mild to very severe as shown in the pictures above. The amount of mitral regurgitation in mitral valve prolapse is usually related to the amount of prolapse. In some cases, as discussed in the last section, the chords attaching the mitral leaflet to the heart muscle can snap leading to flail leaflet and torrential mitral regurgitation!
When there is a mild amount of leak most of the blood is still going forward and the body hardly notices. When there is a severe leak however, so much blood is leaking backward that the body may well not get the blood that it needs. This can lead to symptoms such as fatigue and shortness of breath. Another complication that can be associated with larger degrees of regurgitation is an irregular heart beat that occurs from extra stress placed on the top chamber of the heart that has to accept all the leaking blood.
The table above outlines how we define how severe the leak is. Of course as can be seen in the pictures, echocardiography is the way we usually do this. It’s important to note that although good, it’s not an exact science! So in reality one should look at many factors together when determining how severe the regurgitation is. But in general when less than 30% of the blood in the main chamber leaks backward it is in a milder category, and when more than 50% of the blood leaks backward it is certainly in the severe category. In between is generally considered moderate.
We will discuss the management of mitral regurgitation and complications associated with a significantly leaking valve in further posts.
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