Degenerative Valve Disease/Mitral Valve Disease

Mitral valve disease

Degenerative valve disease (DVD), also called endocardiosis, valvular regurgitation, valvular insufficiency or chronic valve disease, refers to a noninfectious degeneration of the cardiac valves.  The most commonly affected valve is the mitral valve (on the left side of the heart), followed by the tricuspid valve (on the right side of the heart).  The pulmonic and aortic valves are rarely affected by this condition.  For reasons we don’t completely understand, the mitral or tricuspid valve leaflets can become abnormally thickened and develop a nodular appearance in some breeds.  These, and other changes to the valves, impede their ability to form a tight seal between the atrium and ventricle during systole (contraction of the heart muscle) resulting in a leak.  As a result, some of the blood in the ventricle now flows back into the atrium through the leaky valve (known as regurgitation) instead of moving forward from the ventricle into the aorta (on the left side) or pulmonary artery (on the right side) with each beat.

Degenerative Valve Disease Explained:

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Mitral valve disease in the Cavalier King Charles Spaniel

Mitral valve disease is the most common heart disorder in older dogs of all breeds. However, in the cavalier King Charles spaniel (CKCS), the prevalence of MVD is about 20 times that of other breeds. Also in CKCS the onset of the disease typically is much earlier in the life of the dog. 

Breeding Recommendations

Due to the prevalence of MVD in the breed worldwide it is recommended that CKCSs under the age of five years should not be bred unless the MVD breeding program has been followed:

Every breeding Cavalier King Charles Spaniel should be examined annually by a specialist veterinary cardiologist.

Do not breed any Cavalier who is diagnosed with an MVD murmur under the age of 5 years

Do not breed any CKCS before age 2.5 years.

Do not breed any Cavalier under the age of 5 years, unless its parents' hearts were free of MVD murmurs by age 5 years.

Any litter mates of breeding stock having early-onset MVD (mitral valve murmurs before age 5 years) should be taken into very serious consideration. All CKCS breeding stock should be examined by a specialist veterinary cardiologist at least annually and cleared by the veterinary specialists for MVD, the closer the examination to the breeding the better. It is recommended that all cavaliers, breeding stock or not, be examined annually by board certified veterinary cardiologists after age one year.

© CardioRespiratory Pet Referrals Victoria 2012