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What Is Dilated Cardiomyopathy (DCM) in Dogs?

A red heart with a dog lying next to it

In recent years, non-hereditary canine dilated cardiomyopathy (DCM) has become a hot topic in the veterinary world and among worried dog owners. Why? There has been an increase in cases of dogs without a hereditary preposition losing their lives to DCM over the past decade. DCM now accounts for over 10% of all heart diseases in dogs.

What Is Canine Dilated Cardiomyopathy?

Canine dilated cardiomyopathy may sound extremely complicated, but with a bit of knowledge of anatomy, it’s easy to understand.

Understanding the Heart’s Normal Function

As you likely know, the heart has a big job to do. It circulates blood throughout the body, delivering oxygen to vital organs, muscles, and other essential body parts, including the brain. It also helps the body to get rid of carbon dioxide.

Essentially, the heart functions like a refuelling and waste removal station for blood. The heart takes in blood after the oxygen has been replaced with carbon dioxide and removed carbon dioxide and replenishes the oxygen before sending the blood back through the body. This cyclical process requires blood to only flow in one direction. Special muscles and valves pair up to ensure that blood is let into each chamber at the right time to prevent backflow. These muscles are triggered by an electrical impulse that tells the valve to open and close.

DCM: A Malfunctioning Heart

Dilated cardiomyopathy occurs when this system doesn’t function correctly due to weak muscle cells. The weakened cells may not contract, contract fully, or misfire, resulting in an irregular heartbeat. This leads to blood not circulating out of the heart. The excess volume causes the heart to become enlarged or “dilated.” Over time, this dilation can become so severe, the valves that prevent backflow cannot properly close. This causes what most people know as a “heart murmur.” 

Without the proper flow of blood through the body, organs and muscles cannot function properly. This is why many dogs with DCM can have fainting spells, weakness in the muscles, and even sudden heart failure. 

What Dogs Are at the Highest Risk for DCM?

three boxers sitting in a row. one is looking at the camera.

Giant breeds and large dog breeds are the most often affected by DCM. There are some breeds that get DCM more frequently as well. These include

      • Doberman Pinschers
      • Boxers
      • Cocker Spaniels
      • Great Danes
      • Irish Wolfhounds
      • Golden Retrievers

Older dogs, over four years, also have DCM more frequently.

Sign and Symptoms of DCM in Dogs

During your annual vet visits, your vet will listen to your dog’s heart for any irregularities. This is the most common way dogs are diagnosed. However, if you ever notice your dog experiencing any of these common signs of canine DCM, you will want to contact your vet:

  • Weakness
  • Lack of appetite for several days
  • Trouble breathing
  • Panting
  • Wheezing and coughing
  • Bloating of the belly
  • Crackling sound in the lungs
  • In ability to stand

Progress on a Cause for DCM

A dog smiling having its heart listened to by a vet

In September of 2020, the U.S. Food and Drug Administration partnered up with leading vets, university experts and industry experts to try to find the culprit that has been causing a rise in non-hereditary DCM in dogs across the globe [1]. They suspected that grain-free foods and in the increase in peas and pea protein in dog foods may have been the cause. However, in 2022, the FDA released a statement saying that the link between a grain-free diet and DCM cannot conclusively be made.

However, the exact cause of DCM is still not completely understood. Yet many scientists are beginning to connect taurine deficiencies to a higher likelihood of DCM. Taurine, an amino acid, plays a pivotal role in the formation and function of heart muscle cells. 

Many vets and scientists also speculate that low levels of L-carnitine in a dog’s diet can also lead to DCM. 

A Diet That Supports a Healthy Heart

Dog food with raw chicken and chicken hearts

If your dog has a hereditary predisposition to DCM, or if they’re a medium to giant breed, it’s vital that you feed them a heart-healthy diet

The first step is to provide your dog with ample amino acids, including taurine and L-carnitine. These can be found in higher levels in meats, including chicken, turkey, duck, fish, and organ meats–and many vets recommend a BARF diet as the best source for a taurine-rich diet. L-carnitine can be found in red meats, like kangaroo and beef, in addition to fish and poultry.

Always provide your dog with a diet with real meat as the number-one ingredient. And never feed your dog a vegetarian or vegan diet. These do not contain the full range of essential amino acids dogs need to thrive.

DCM in Dogs: The Takeaway

Sadly, canine dilated cardiomyopathy is irreversible once a dog has been diagnosed. But many dogs live long, fulfilling lives post-diagnosis. Always check your dog's diet to be sure it's rich in taurine and L-carnitine from real meat, and don't skip your dog's annual vet visits.