Mitral valve insufficiency is the most common of the acquired cardiac diseases in older dogs, affecting over 1/3 of dogs older than 10 years. However, in certain breeds including the Cavalier King Charles Spaniel, mitral valve insufficiency develops at a younger age, due to an inherited predisposition for the disorder.


The first signal that a dog might have Mitral Valve Disease is the development of a heart murmur. However, a dog with a heart murmur may live a full life span, depending up the progression of the disease in that particular dog. Some dogs that have developed heart murmurs at young ages have lived to the average lifespan of that breed. A veterinarian, while listening to a dog's heart, may hear a heart murmur on the left side. (Please note there are other causes for heart murmurs. To diagnose MVD, it will depend upon where the regurgitation is heard). The veterinarian will then grade the murmur for severity from Grade 1 (mild) to Grade 6 (severe) and depending upon the grade will advise proper treatment.

Severe Mitral Valve Disease will eventually lead to Congestive Heart Failure.

Implication for Owner

The Cavalier will have their heart checked during his or her annual visit to the veterinarian. Cavaliers that develop murmurs might have early signs of MVD. If the disease is present and progresses, the murmur will become more audible, the dog may become intolerant of exercise, respiratory rate will increase, fluid will begin to accumulate in the lungs and the dog will develop coughing and labored breathing.  In most cases, a Cavalier will not need heart medications until late in life.  There are treatments available to assist with management of advancing MVD. A board Certified Veterinary Cardiologist should be consulted to determine the exact mode of therapy for each Cavalier. 

The recommended health screenings for Cavaliers are annual auscultations (listening to the heart with a stethoscope) by board certified cardiologists and doppler (Echocardiogram) if there is a question on auscultation.  The ACKCSC, Regional Cavalier clubs and local AKC all Breed Clubs are hosting and making health clinics with cardiologists accessible to breeders and owners throughout the USA.   Currently, the recommended practice is to wait until a Cavalier is two years old or older before the first breeding and to know the parents and ancestral cardiac status.  Cavaliers with early onset presentations of MVD (before four years of age) should not be bred and breeders need to work with the guidance of their cardiologists.

Another important factor in Mitral Valve Disease is the rate of progression of the disease (if present) and this is why breeders and owners are recommended to continue to monitor their Cavalier's heart on an annual basis.

By having Cavaliers screened annually by board certified cardiologists for evidence of heart murmurs and breeding unaffected older dogs, breeders are striving to move the age of onset of the disease as far as possible.  Some Cavaliers have not presented with cardiac disease even at advanced ages.  In reality though, cardiac diseases cannot be totally eradicated in dogs or humans.



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