This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Note for Pet Owners:
If you have an animal diagnosed as having this disorder there are some important guidelines that you should follow:

  • Always give the medications that your veterinarian has prescribed at the correct dose and at the correct times
  • Contact your veterinary practice if you are concerned that your animal is having a relapse, or if it appears to react abnormally following treatment. Your observations may simply be normal side-effects to the treatment - but they may not be and, even if they are common side-effects, the drug dosage may need to be altered.

Topics on this Page:


Dilated cardiomyopathy is a common form of cardiomyopathy.

Breed Occurrence
Dilated cardiomyopathy is most commonly seen in large breed dogs including the
Doberman Pinscher, Cocker Spaniel, Springer Spaniel, Boxer, Irish Setter, German Shepherd Dog, Great Dane, St Bernard and Irish Wolfhound. It is usually seen in young adult male dogs (mean age of presentation to a veterinarian 4-6 years of age).

It is also seen in young to middle-aged cats (mean age reported to be 7.5 years) and, although all breeds can be affected, there is a higher incidence in the Siamese, Abyssinian and Burmese breeds. In cats this form of heart muscle disease was associated with taurine deficiency but this is now rare.

Age prevalence
In dogs dilated cardiomyopathy can occur at any age, but in most breeds of dog dilated cardiomyopathy occurs at a mean age of 4-6.5 years, whereas in the Boxer it occurs slightly later (at an average age of 8 years).

In cats dilated cardiomyopathy can occur at any age with a mean age of onset of about 7.5 years.

Sex prevalence
Males are usually affected more frequently than females with this disease, except for Boxers and English Cocker Spaniels in which breeds studies suggest both sexes are equally affected.

In cats there are conflicting reports about whether or not one sex is affected more than the other.

In dogs the condition can be present for a long time with no obvious symptoms, then the clinical signs often start suddenly and include the typical signs of
heart failure including both forward and backward failure. Commonly seen signs include difficulty breathing (called dyspnoea), a cough, feinting, exercise intolerance and a swollen abdomen. Affected dogs often have reduced appetite and weight loss.

In cats signs include difficulty breathing, lethargy, vomiting and poor appetite. Feinting is rare in cats with this disease.

On plain radiographs all forms of dilated cardiomyopathy may show as bilateral enlargement of the heart (called cardiomegaly) . In some breeds there may be evidence of fluid accumulation in the lungs (called pulmonary oedema) - Doberman and English Cocker Spaniel and cats; or free fluid in the chest (called pleural effusion) - Dobermans.

In cats a dilated caudal vena cava, enlarged liver and free abdominal fluid (ascites) may be present.

Ultrasound (called echocardiography)
Moving (M-mode) echocardiography is the best diagnostic tool to use to confirm the diagnosis of dilated cardiomyopathy because it clearly shows dilation of the heart chambers with severely reduced shortening fraction of the heart wall when the heart muscle contracts.

A Provet Educational Video on "An introduction to Echocardiography" by Malcolm Cobb and Rebecca Stepien can be obtained from the Provet On-line Store.

Also, Provet have launched an On-line Certificate Course on Ultrasonography for veterinarians  go to www.provet.co.uk/ultrasound/home.htm 

Unless a specific underlying cause can be determined e.g.
taurine deficiency, L-carnitine deficiency, treatment can only be symptomatic and are the same as those commonly used to treat heart failure.

Recently it has been suggested that an imbalance in the oxidant-antioxidant system may be involved in the cause of this disorder. .Click here for more information

The prognosis is always guarded to poor at the outset with the average survival time being 6 months and 80% of dogs with atrial fibrillation die in this period.
Dobermans often die within days or weeks and rarely survive for more than a year, whereas some breeds (including German Shepherds and Great Danes) often respond well and can survive more than 2 years.

The prognosis is good for dilated cardiomyopathy associated with taurine deficiency in cats, as correction of the nutritional deficiency effectively reverses the disease.


Updated January 2016