Back to Fact Sheets

Mitral valve disease

Download PDF

What is mitral valve disease (MVD)?

Mitral valve disease is a common heart disease in dogs caused by age-related changes to the valves of the heart. MVD is most commonly seen in older, small breed dogs (including Cavalier King Charles Spaniels, Dachshunds, Chihuahuas, Terriers, Schnauzers, Bichons, and Poodles), but can also be seen in our medium to large breed dogs (Spaniels, Lurchers, Labrador Retrievers).

The mitral valve is the thin, delicate tissue that separates the two chambers on the left side of the heart: the left atrium (top chamber) and the left ventricle (bottom chamber). In MVD, the valve becomes irregular and droopy; this results in an imperfect seal and leakage through the valve. This backward leakage (called mitral regurgitation) is turbulent and can be heard on examination as a heart murmur.

Cavalier King Charles Spaniel dog outdoors in nature

What are the consequences of MVD?

As this disease progresses with age, the number of mitral regurgitation increases. In response, the heart enlarges to accommodate this increased volume. In advanced cases, if the heart can no longer compensate, fluid may back up into the lungs resulting in congestive heart failure (CHF).

How is MVD diagnosed and monitored?

Diagnosis of MVD is made with an echocardiogram (ultrasound of the heart) by a veterinary cardiologist. Following initial diagnosis, regular checkups are recommended to monitor progression and start medications if needed. If heart failure is suspected, chest x-rays will also be recommended to look for fluid in the lungs.

How is MVD treated?

Unfortunately, there are no treatments that can stop or reverse changes to the mitral valve, as this is an age-related disease. Before the development of heart enlargement, no treatment is necessary. Once the heart enlarges, treatment with pimobendan has been shown to delay the onset of heart failure in dogs with MVD. If symptoms of heart failure are present, treatment with diuretics +/- additional drugs to reduce scar tissue formation, control abnormal rhythms, or electrolyte supplements may be added.

In the UK, we are lucky to have an option for surgical repair of the mitral valve. This is a major, open heart surgery that involves cardiopulmonary bypass and can be quite costly; therefore it is not right for every patient or family. If you are interested in a referral for heart surgery, please ask your cardiologist for further information.

How should I care for my dog with MVD at home?

Before the onset of heart failure, most dogs can live normally with no restrictions. Special diets are not required, though very salty foods (human foods, jerky treats) should be avoided. We advise dogs to avoid non-traditional diets high in legumes (lentils, peas, chickpeas, etc).

Dogs with MVD should be monitored for symptoms of worsening heart disease including shortness of breath, exercise intolerance, cough or fainting. If these signs are noted, please contact a veterinarian. We will also ask you to monitor your dog’s sleeping breathing rate at home. A normal breathing rate (while sleeping) is less than 36 breaths/minute. The Cardalis app can help you count and track this rate at home.

What is the prognosis of MVD?

It is important to note that although many older dogs have MVD, only 25-50% go on to experience symptoms of heart failure. Therefore, many dogs will not have their lives shortened by this disease. If signs of heart failure do occur, this often happens several years after a heart murmur is first detected. After the onset of heart failure, if treated, most dogs continue to have an excellent quality of life and can often live an additional year, though survival time varies widely between dogs.

Linnaeus Veterinary Limited trading as Davies Veterinary Specialists 01582 883950

©2024 Davies Veterinary Specialists