Heart valve disease in dogs and cats - Causes, symptoms and treatment

Heart valve diseases are common heart problems in dogs and, to a lesser extent, also occur in cats. The valves in the heart ensure that blood flows in the correct direction. When a valve shows an abnormality, as with mitral valve degeneration (MMVD) or tricuspid valve abnormalities, the heart can pump blood around the body less efficiently, and with further progression, heart failure often develops.

In this article, we discuss the causes, symptoms, diagnosis, and treatment options for heart valve disease in dogs and cats.

What is heart valve disease?

The heart has four valves: the mitral valve, tricuspid valve, aortic valve, and pulmonary valve. They ensure that blood flows in one direction. In a valve abnormality, the valve does not close properly, causing blood to leak backward (regurgitation), or the valve becomes narrowed (stenosis). This leads to increased strain on the heart and ultimately to heart failure.

Mitral valve degeneration (MMVD)

MMVD is the most common heart disease in dogs, especially in small and medium-sized breeds such as Cavalier King Charles Spaniels and Poodles. Certain parts of the mitral valve (located between the left atrium and left ventricle) become thickened and no longer close properly. This causes blood to flow backward, which eventually leads to enlargement of the heart. In later stages of the disease, this can cause fluid buildup in the lungs.

Tricuspid valve abnormalities

The tricuspid valve is located between the right atrium and right ventricle. Abnormalities of this valve are less common but lead to backflow of blood/increased pressure toward the large veins (vena cava). This can cause various complaints, such as fluid buildup in the abdomen (ascites) and increased pressure in certain blood vessels in and around the liver.

Other valve abnormalities

Both dogs and cats can also have congenital valve abnormalities, such as pulmonary stenosis or aortic stenosis. These conditions are rarer but can cause serious complaints and often require specialized treatment.

Symptoms of heart valve disease

• Exercise intolerance (getting tired faster)
• Shortness of breath and rapid breathing
• Fainting spells or collapse
• Distended abdomen due to fluid buildup
• Weight loss and reduced appetite

In early stages, there are often no symptoms present yet.

Diagnosis of heart valve disease

Diagnosis is made using a combination of examinations:

• Physical examination: listening for a heart murmur with a stethoscope
• Echocardiography: heart ultrasound to visualize the valves and blood flow
• X-rays: assessing heart size and lungs
• ECG: assessing heart rhythm
• Blood tests: including the NT-proBNP test to support the diagnosis of heart failure

Treatment of heart valve disease

Heart valve diseases are usually chronic and progressive, but with the right treatment, the animal's quality of life can be greatly improved:

• Medication such as diuretics (water tablets), pimobendan, and anti-arrhythmics
• Low-sodium diet and adjusted exercise pattern
• Regular check-ups with the veterinarian

At a few specialized centers, heart surgery or catheter intervention can also be performed, such as balloon valvuloplasty and ablation, but this is still limitedly available for animals.

Prognosis

The prognosis depends on the severity of the valve abnormality and the stage at which the disease is discovered. With medication and good monitoring, many dogs and cats can maintain a good quality of life for years. That is why it is very important to carry out good screening, even when no clinical symptoms are present yet.

Want to know more?

Read more about cardiology and the treatment options at Nesto. Our specialized veterinarians have extensive experience with the diagnosis and treatment of heart valve disease in dogs and cats.

Frequently asked questions (FAQ)

What is the most common heart valve disease in dogs?

Mitral valve degeneration (MMVD), especially in small breeds such as Cavalier King Charles Spaniels.

Does heart valve disease also occur in cats?

Yes, although less often. In cats, other heart diseases such as HCM are more commonly seen, but valve abnormalities can also occur.

How is heart valve disease diagnosed?

Through physical examination, ultrasound, X-rays, and sometimes blood tests.

Can heart valve disease be cured?

Usually not, but medication can greatly relieve the symptoms and improve quality of life.

How long can my dog or cat live with heart valve disease?

That depends on the severity, the stage, and which valve is specifically affected, but with good treatment this can often still be several years.