Heart disease is a condition of the heart and blood vessels which affects the way the heart works and prevents oxygen being transported normally around the body. Heart disease may be present when the animal is born, however the majority develop in adulthood, 10% of dogs aged between 5-8, 20-25% of dogs aged between 9-12 and 30-35% of dogs aged 13+. Heart disease usually strikes cats around 4-6 years of age.

Common types of heart disease

Degenerative Mitral Valve Disease (DMVD)

Degenerative mitral valve disease is the most common of heart disease in dogs. This can affect any breed but is more commonly seen in the smaller dogs. The problem arises when the mitral valve in the heart degenerates and changes shape over time. This valve becomes leaky and causes a heart murmur which can be heard when the heart beats. This sound can detected by your vet at a routine examination and can be the first indication of a problem.

Dilated Cardiomyopathy (DCM):

Dilated cardiomyopathy can be seen in both dogs and cats, although is far more common in the dog. This is a disease of the heart muscle which results in thinning of the heart wall, and weakened pumping ability. DCM can be responsible for collapse and sudden death, especially in certain breeds such as the Doberman.

Hypertrophic Cardiomyopathy (HCM)

Hypertrophic cardiomyopathy is the most common acquired form of heart disease in cats. With this disease the heart muscle becomes thickened and prevents the heart relaxing, filling and pumping properly.

Congenital heart diseases are seen less often, but may include malformations of valves or a failure of the closure of a blood vessel.

Breeds at risk of heart disease

There are 7 breeds of dogs that are at risk of heart disease which are:-

Cavalier King Charles Spaniels


Miniature and Toy Poodles



Golden Retrievers

Miniature Schnauzers

  There are 6 breeds of cats that are at risk if heart disease which are:

Maine Coon





American Shorthairs

Signs and symptoms

There are 10 signs of heart disease:-

  1. Persistent cough
  2. Difficulty breathing
  3. Fainting / Collapsing
  4. Abdominal swelling / distension
  5. Exercise intolerance
  6. Heart murmur
  7. Change in heart rate
  8. Change in body weight
  9. Restless or hiding
  10. Loss of appetite

How is heart disease diagnosed?

A combination of tests are usually required to diagnose heart disease, these include:-

  1. X-rays
  2. Blood pressure monitoring
  3. Blood tests
  4. Electrocardiography (ECG)
  5. Ultrasound

For the more difficult cases we have Dr Babis Koffas, European Specialist in Small Animal Cardiology, who will come to any of our four surgeries.


The majority of heart diseases are managed with medication. These will have effects on the heart to improve the quality of the heartbeat and reduce pressures that the heart has to work against.

We recommend bringing your cat or dog to see us twice a year. A regular checkup could easily spot the early warning signs of heart disease in cats or dogs. Prevention, proactive care is the best kind of support we can offer our pets to ensure they live long, healthy and happy lives.

If you have any concerns about your cat or dog then please do not hesitate to contact any of our four surgeries.