What are the signs of mitral valve disease in dogs?

Heart murmur found at a check-up; Cough; Faster breathing at rest; Tiring on walks; Fainting.

When should I contact a veterinarian?

Count your dog's breaths while it sleeps. Over 30 breaths a minute, repeatedly, needs a vet call.

Heart disease · Updated 2026-09-29

The most common heart disease in dogs: a leaky valve that can lead to heart failure, especially in small breeds.

Prompt veterinary attentionDogs

Age-related thickening of the mitral valve; strongly inherited in breeds such as the Cavalier King Charles Spaniel.

Listening to the heart, chest X-rays and heart ultrasound (echocardiography).

Some dogs with an enlarged heart benefit from medication before signs appear; heart failure is treated with several medications.

Not preventable; breeding schemes with heart screening reduce risk.

Many dogs live years with a murmur; once heart failure develops, treatment extends good-quality life.

What are the signs of mitral valve disease in dogs?: Heart murmur found at a check-up; Cough; Faster breathing at rest; Tiring on walks; Fainting.
What causes mitral valve disease in dogs?: Age-related thickening of the mitral valve; strongly inherited in breeds such as the Cavalier King Charles Spaniel.
How is mitral valve disease in dogs diagnosed?: Listening to the heart, chest X-rays and heart ultrasound (echocardiography).
How is mitral valve disease in dogs treated?: Some dogs with an enlarged heart benefit from medication before signs appear; heart failure is treated with several medications.
Can mitral valve disease in dogs be prevented?: Not preventable; breeding schemes with heart screening reduce risk.
When should I contact a veterinarian?: Count your dog's breaths while it sleeps. Over 30 breaths a minute, repeatedly, needs a vet call.