Mitral valve disease (MVD) in dogs
October 21, 2021
There are many different heart conditions that can affect our dogs; however, mitral valve disease (MVD) is by far the most common. But what is MVD, and how do you know if your dog has it?
We explore further below:
What is mitral valve disease (MVD)?
Also referred to as degenerative valve disease, MVD involves the degeneration of the heart valve separating the two chambers on the left side of the heart. As a chronic progressive disease, it will worsen over time.
The heart has four valves, one of these being the mitral valve. The purpose of the valves is to control the flow of blood around the heart each time it beats. When the heart beats, the valves allow blood to pass through then close to stop any blood leaking back into the initial chamber. MVD causes the valve between the left atrium and left ventricle to thicken, resulting in the valve not being able to close properly and blood leaking back through as a result. This leak is heard as a heart murmur.
The knock-on effect is that greater pressure is put on the heart to work harder and pump the blood around the body. The heart also enlarges due to the need to pump harder to compensate for the loss caused by the initial backflow (‘regurgitation’). The heart may be able to cope with this over a long period; however, at a certain point, the pressure becomes so high that blood accumulates in the blood vessels of the lungs causing fluid to leak into the lungs – the result is congestive heart failure.
How severe is MVD?
We already know that MVD is a chronic and progressive disease, with the worsening effects outlined above, but that doesn’t mean that all dogs with the disease go on to develop heart failure. The various stages of the condition have been classified as below:
STAGE A – Breeds prone to MVD with no current symptoms or murmur
STAGE B1 – A murmur is present but there are no symptoms and no evidence of heart changes on imaging
STAGE B2 – A murmur is present with signs of enlarged heart but no heart failure
STAGE C – Showing signs of heart failure such as coughing, breathing problems, exercise intolerance, or collapse.
What are the symptoms?
Symptoms of MVD may not display easily and in some cases, affected dogs can live their entire lives without showing any signs of the disease. The main symptom for diagnosing MVD is the presence of a heart murmur – this will only be picked up during a routine examination by one of our vets where they can listen to your dog’s heart.
There may be other signs that could indicate the onset of MVD, including:
- coughing (after lying down or sleeping, and often worse at night)
- slowing down on walks or displaying low energy in general
- breathing quicker than usual, with breathlessness and/or panting
- weight loss
- fainting or collapsing.
If in any doubt, it is always best to get your dog seen by us. On detection of a heart murmur, further tests may be required to confirm the diagnosis.
Are certain breeds of dogs at higher risk?
MVD can affect any dog, but it is most common in small to medium sized breeds, and dogs that are middle-aged to senior. When it comes to individual breeds, it is once again more common in the:
- Cavalier King Charles spaniel
Can MVD be cured?
As it currently stands, there is no cure for the condition. But the advances in modern medicine mean that if the condition is caught early, there is a good chance that dogs can lead happy lives using a combination of drugs to both control the disease and prolong life. Valve replacement surgery is possible in a small number of cases.
If you have any concerns about your dog, please get in touch or book an appointment.