What is degenerative mitral valve disease in dogs?
Chronic degenerative valve disease in dogs (CVD) affects the mitral valve in the heart. It is a slow and progressive degeneration of cells. This abnormal backward leaving of the blood through the valve, called regurgitation, causes a heart murmur which your veterinarian can detect with a stethoscope.
The thickening of the valve and leaking of the valves causes heart enlargement and the heart muscle weakens over time. Once the time comes when the heart can no longer accommodate the abnormal blood flow, congestive heart failure begins. This is demonstrated by coughing and difficulty breathing.
How many heart valves does a dog have?
The heart is divided into right and left sides and is responsible for pumping blood to and from all tissues in the body. The right side of the heart pumps oxygen-deficient blood through the lungs where it is re-oxygenated and carbon dioxide waste is removed. The re-oxygenated blood then enters the left side of the heart where it is pumped out to the body through the aorta and other arteries.
Each side of the heart has two chambers, an upper atrium and a lower ventricle, and two valves, the tricuspid on the right and the mitral on the left. These valves act as one-way gates allowing blood to flow from the upper atrium to the lower ventricle and preventing blood from flowing backward into the atrium when the ventricle pumps.
What causes heart valve problems in dogs?
Chronic degenerative valve disease most often affects small-breed dogs and is associated with aging. Up to 75% of small breed dogs show evidence of CVD by 7 years of age. Certain breeds, such as the Cavalier King Charles spaniel and dachshund can be predisposed to this disease.
Large-breed dogs are less prone to develop this condition.
What are the symptoms of a dog with heart problems?
Several symptoms may present in a dog with chronic degenerative valve disease, however, these symptoms can also occur with other diseases. It is important to notify your vet if you notice any of these symptoms so that your dog can be assessed and your vet can determine the underlying cause.
Not every dog will develop all the following symptoms and many dogs will have more than one.
- Weight loss
- A lethargic or depressed attitude
- Reduced ability to exercise
- Collapse or fainting
- Distended belly
- Rapid and shallow breathing when resting or sleeping
- Restlessness or agitation while sleeping
- Changes in the position that your dog sleeps in
- Coughing or gagging
- Decreased appetite
What is the treatment for chronic degenerative valve disease in dogs?
In the asymptomatic stages, medication is not required when the heart is not enlarged and blood pressure is normal.
If heart enlargement is detected and high blood pressure, medications may be prescribed to treat heart failure. These medications will be continued throughout your dog's life, although the doses and frequency of administration may change over time.
As the disease progresses, the goal is to help your pet maintain a good quality of life and to keep your pet out of heart failure, without harming the kidneys.
How long can a dog live with mitral valve disease?
The majority of dogs with asymptomatic CVD will live 2 to 5 years or longer, without ever developing any clinical signs of heart failure.
Dogs can live one to two years with appropriate treatment and frequent monitoring. Your veterinarian will work with you to manage the treatment and may adjust the medication to help maintain your dog’s quality of life.