Australian Shepherd Health & Genetics Institute

Australian Shepherd Health & Genetics Institute

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Mitral Valve Disease


What is mitral valve disease (MVD)?

The mitral valve is located between the two chambers on the left side of the heart.  Myxomatous Mitral Valve Disease (MVD) is a gradual degradation of that valve which allows small amounts of blood to flow the wrong direction through the valve causing the heart to work harder.  Eventually it leads to congestive heart failure.

 How do I know if my dog has MVD?

In early stages the only sign is a heart murmur.  If that is not detected the first signs apparent to an owner would be those of congestive heart failure:  Coughing, lethargy and fainting.  However, if the dog is being presented for routine veterinary care the murmur will be found.  Chest x-rays, electrocardiogram and echocardiogram may be used to confirm the diagnosis.

 What does having MVD mean for my dog?

MVD cannot be cured.  Mitral valve replacement surgery is possible but the dog must be relatively healthy.  Treatment is generally confined to managing the heart failure through medication and low-sodium diet.  Optimal weight – neither heavy nor thin – must be maintained and it may be necessary to limit physical activity.  Depending on age of onset and progression, MVD can shorten lifespan.

 How common is MVD in Aussies?

Rare.  Most dogs are over 10 years when diagnosed.

 Is MVD inherited?

It is inherited in some breeds but is also a common old dog degenerative heart issue.  In dogs over 10 years it is probably due to wear and tear.  In younger dogs, particularly if they are several years younger, it might be inherited.

 What does MVD mean for my breeding program?

Don’t breed dogs that develop early onset (under 10 years) MVD.  If there are other members of the family who have MVD it should be assumed to be inherited.   Do not repeat the cross that produces it.  Parents and healthy full and half siblings should not be bred close on the pedigree that produced MVD and only to mates with no family history of MVD in dogs under 10.