What Is Dilated Cardiomyopathy in Dogs?

Dilated cardiomyopathy (DCM) is the second most common heart disease in dogs. Certain breeds are genetically predisposed to this condition, but it can affect dogs of any breed makeup, including mixed breed dogs. Veterinarians and veterinary researchers are unsure why dogs develop this disease, but genetics, infection, environmental causes, and diet are possible risk factors.

What is DCM?
When a dog has DCM, the left ventricle of their heart becomes enlarged and loses its ability to contract properly. Then, the heart must work harder to pump blood, and the muscle walls become weaker and thinner. As the condition progresses, it can lead congestive heart failure and eventually death.

What Causes Dilated Cardiomyopathy?
DCM is most commonly seen in large breed dogs. Certain breeds may have a genetic mutation that predisposes them to developing the condition during their lifetime. Breeds known to be susceptible to DCM are the Doberman Pinscher, the Great Dane, the Boxer, and the Cocker Spaniel.
In recent years, there has been an increase in cases of dogs with DCM of breeds not known to be susceptible to the disease. Data from the FDA has shown that most ate nontraditional, grain-free diets containing peas as a main ingredient. The dogs were all deficient in taurine, an amino acid that dogs normally synthesize in their bodies. Some affected dogs have shown improvements after switching to a grain-inclusive diet supplemented with taurine in addition to medication and other therapies.

What are the Symptoms of DCM?
In the early stages of DCM, there are usually not any noticeable symptoms.
As the condition progresses, the heart will fail to efficiently pump blood throughout the body. Symptoms like getting tired more quickly, collapsing, and fainting spells are common.
When the heart is unable to pump blood, it can build up around the lungs, and fluid can leak into surrounding tissues. This can cause swelling in the chest cavity and also causes trouble breathing and coughing.

How is Dilated Cardiomyopathy Treated?
If your dog is at increased risk for DCM, it’s a good idea to have your veterinarian monitor their heart at regular checkups. Dogs with DCM will have an enlarged heart that is evident on radiographs. Your veterinarian may follow up with an electrocardiogram (ECG) or an echocardiogram to evaluate the severity of the disease.
There is no cure for DCM, but it can be managed with medication. Unfortunately, most dogs die within a few weeks to two years after diagnosis.
Vetmedin (pimobendan) is a prescription medication that helps dogs with DCM pump blood more efficiently. A diuretic such as Furosemide (Salix) can reduce fluid retention.

Should I Change My Dog’s Food?
While the FDA has not confirmed a link between grain-free diets and DCM, you may be wondering if you should switch your dog’s food as a precautionary measure. If you believe your dog may be at risk for developing DCM, talk to your veterinarian about regular screening for heart disease.
If your dog does not have a known allergy to grains, you can try a grain-inclusive kibble or, better yet, switch to a dehydrated raw dog food or a fresh raw or cooked diet. You can also supplement your dog’s diet with taurine and omega-3 fatty acids to support their heart health.