Mitral Valve Disease - a common heart valve condition in dogs

Mitral Valve Disease - a common heart valve condition in dogs

Important beforehand: Fidello is not a veterinarian. This page is meant to inform you and does not provide a diagnosis. Are you unsure about your dog's health, or do you recognise the signs described below? Always contact a veterinarian.

Mitral valve disease is the most common heart condition in dogs. It develops when the mitral valve - the valve between the left atrium and the left ventricle of the heart - gradually thickens and becomes deformed. As a result, the valve no longer closes properly, and with every heartbeat some blood leaks back the wrong way. The condition usually develops slowly over years and is seen mainly in older dogs and in smaller breeds.

What is mitral valve disease?

In mitral valve disease, also known as myxomatous mitral valve degeneration, the tissue of the valve leaflets gradually changes structure: it thickens, becomes deformed, and no longer closes tightly. Because the valve no longer shuts properly when the heart contracts, part of the blood flows back into the left atrium instead of fully into the main artery. This is called mitral valve insufficiency or mitral regurgitation. In the early stages, a dog usually shows no signs of this, because the heart can compensate for the backflow for a long time. As the valve deteriorates further, the heart has to work harder and the heart chambers can gradually enlarge, which may eventually lead to heart failure.

Which dogs are at risk?

Mitral valve disease is strongly breed-related and is reported most often in small and very small dog breeds, such as the Cavalier King Charles Spaniel, Miniature Poodle, Chihuahua, Dachshund and Yorkshire Terrier. In the Cavalier King Charles Spaniel, a hereditary predisposition to this valve defect has been extensively researched and described, and the condition can appear at a relatively young age. In most other breeds, the risk mainly increases with age: the condition is seen more often in older dogs. A hereditary predisposition or belonging to a susceptible breed does not mean a dog will automatically develop symptoms.

Symptoms

In an early stage, mitral valve disease usually causes no noticeable symptoms; often a heart murmur - an unusual sound the veterinarian hears when listening to the heart - is the first sign. As the condition progresses, signs can develop such as tiring more quickly during walks, faster breathing at rest, coughing (especially at night or after excitement), and reduced appetite. Signs that require urgent attention are: obvious breathing difficulty, fast and shallow breathing at rest, bluish discoloured gums, or a dog that suddenly collapses or faints.

When to see the vet

Always have a heart murmur noticed by the veterinarian investigated further, even if your dog does not yet show any symptoms. Also contact the vet in case of persistent coughing, faster breathing at rest, reduced stamina, or listlessness. In case of sudden severe breathing difficulty, bluish gums or fainting, an emergency appointment is needed.

How is it diagnosed?

A veterinarian usually first hears a valve defect as a heart murmur when listening to the heart with a stethoscope. To determine the severity and stage of the condition, further tests often follow, such as echocardiography (a heart ultrasound) to assess the valve and the size of the heart chambers, a chest X-ray to check heart size and the lungs, and sometimes blood tests or a blood pressure measurement. This page cannot determine whether your dog has mitral valve disease; only a veterinarian can assess that after examination.

Treatment in outline

The approach depends on the stage of the condition and is determined by the veterinarian. As long as a dog has no symptoms, targeted medication may be considered to slow the deterioration. Once there are signs of heart failure, a combination of medications is often used to reduce the strain on the heart and counteract fluid in the lungs. There is no treatment that reverses or cures the valve defect; the goal of treatment is to support quality of life and slow the progression of the disease.

What you can do yourself

Alongside the treatment set out by the veterinarian, you can contribute to your dog's comfort at home: keep your dog's weight under control, since excess weight puts extra strain on the heart, choose calm, regular exercise rather than short, intense exertion, and watch for signs of tiredness or breathlessness during walks. Always discuss any changes to exercise or diet with the veterinarian. This does not replace medical treatment, but it can contribute to daily comfort.

Prevention and responsible breeding

In breeds with a known increased risk, such as the Cavalier King Charles Spaniel, responsible breeders have the parent dogs' hearts examined before breeding, for example by having a cardiologist listen to the heart and, if needed, perform an echocardiography. As a buyer, ask about these results and about the age at which the parent dogs were last examined. This reduces the risk of valve defects in offspring, although it offers no complete guarantee.

Living with mitral valve disease

Many dogs with mitral valve disease live for years without noticeable symptoms, especially when the condition is detected early and regularly monitored by the veterinarian. Regular check-ups make it possible to spot changes in time and adjust treatment where needed. A calm daily routine, a healthy weight, and avoiding excessive stress or strenuous exertion can contribute to a more stable situation.

Frequently asked questions

Is mitral valve disease contagious?
No, it is a non-contagious, degenerative condition of the valve tissue.

Can my dog suddenly die from this?
The condition usually progresses gradually, but in an advanced stage acute deterioration can occur. Discuss with the veterinarian what this could mean for your dog.

Is a heart murmur always mitral valve disease?
Not necessarily; a heart murmur can have various causes. Only further examination by the veterinarian can establish the cause.

Can diet prevent mitral valve disease?
There is no diet that prevents or cures the condition; a healthy weight can help reduce the strain on the heart.

Conclusion

Mitral valve disease is the most common heart condition in dogs and usually develops gradually, especially in smaller and older breeds. Early detection through regular veterinary check-ups, and timely treatment when needed, make a real difference in how long and how comfortably a dog with this condition can live.

Finally

Finally: this article does not replace a visit to the veterinarian. Fidello does not provide diagnoses or prescribe treatments. If in doubt, in case of persistent symptoms, or urgent signs, a veterinarian is always the right next step.