Australian Shepherd Health & Genetics Institute

Australian Shepherd Health & Genetics Institute

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Mitral Valve Disease

France-flagGermany-flagRev. March 2014


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.  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.  MVD cannot be cured.  Mitral valve replacement surgery is possible but the dog must be relatively healthy.  Treatment is 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.   Most dogs are over 10 when diagnosed.

MVD 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.  Affected dogs should not be bred.  If the dog is under 10 years and there are other members of the family who are affected the disease should be assumed to be inherited.   Do not repeat the cross that produced 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.