Mitral Valve Disease - Cavalier King Charles Spaniel site

Mitral valve disease is the most serious of the inherited diseases affecting the breed. At the onset of this desease the left mitral valve of the heart begins to degenerate and leak, allowing small amounts of blood to flow the wrong way,causing strain on the heart. As the leak progresses, the heart must work harder to pump blood and becomes enlarged. From this point, the dog can go into congestive heart failure.

Mitral valve disease is seldom detected before a dog is one year old, and it usually comes to light when the dog goes for an annual checkup. The vet will hear a murmur through the stethoscope, although there may be no physical symptoms of heart trouble. A Cavalier may continue on with this slight murmur for many years, and the leak may progress so slowly that she remains without symptoms until she is quite old, when degeneration would be expected in any case. In some cases, however, a murmur will be detected and the dog will go downhill rapidly, progressing to congestive heart failure at the relatively early age of 7 or 8.

A Swedish study of mitral valve disease reveals that more than 50 percent of Cavaliers have a murmur detectable by stethoscope by the time they are 4 years old. The normal life span of a Cavalier is 10 to 12 years, and it is the aim of breeders to try to produce puppies who will be healthy and long-lived.

Environmental factors play a part in the progression of mitral valve disease. A dog who is fat and gets little exercise is a prime candidate for the problem.

The diagnosis of mitral valve disease is not a death sentence, and there are a number of helpful drugs that will improve the quality of life for an affected dog. Drugs are usually prescribed when the dog begins to exhibit symptoms such as shortness of breath or coughing. These can be alleviated with one or a combination of drugs, depending upon wich symptoms are parent. Veterinarians can supply prescription diets for dogs who have mitral valve disease; these are usually fairly low in protein with no salt added.