Dilated Cardiomyopathy (Enlarged Heart) in Dogs

Dilated Cardiomyopathy (Enlarged Heart) in Dogs

Dilated cardiomyopathy is a fatal condition in dogs. As a dog parent, you must be aware of the symptoms of this condition and how it happens in the first place. This information can save your dog’s life and should not be taken lightly.

Here’s what you need to know.

What is Dilated cardiomyopathy?

Dilated cardiomyopathy is a condition where the heart is unable to contract properly. This results in a backup of blood in the heart chambers which pushes against its walls. When this happens, the heart enlarges, and eventually, they become thinner. This makes it harder for the heart to pump blood around the body.

As a result, organs and tissues such as the lungs and kidneys which require oxygenated blood to carry out their tasks are affected. This causes a buildup of fluid and an overload in the circulatory system. Eventually, congestive heart failure sets in which is life-threatening.

Signs/symptoms of Enlarged Heart

Unfortunately, the symptoms of an enlarged heart may not be noticeable in its early stages. This may be missed during checkups with the vet, which is why it’s important to have regular checkups for your vet to analyze any changes that may have occurred with your dog over a period of time.

The most common signs/symptoms of an enlarged heart include:

  • Lethargy
  • Weakness
  • Weak or irregular pulse
  • Muffled breathing or crackling sound while breathing
  • Rapid breath
  • Shortness of breath
  • Weight loss
  • Lack of appetite
  • Heart murmur
  • Arrhythmia
  • Vomiting
  • Fainting
  • Coughing
  • Aversion to exercise
  • Abdominal distension (ascites)


While the exact cause of enlarged heart in dogs is not clear, here are some contributing factors:

  • Genetics, large breeds such as American Cocker Spaniels, Boxers, Dalmatians, Doberman Pinschers, English Cocker Spaniels, Welsh Corgis, Tibetan Terriers, Springer Spaniels, Scottish Deerhounds, German Shepherds, Great Danes, Irish Wolfhounds, Saint Bernards, Newfoundland Retrievers, Labrador Retrievers
  • Nutritional deficiency, particular carnitine, and taurine
  • Preexisting conditions, such as hypothyroidism, infections, myocarditis, immune-mediated abnormalities

Treatment Options

Your regular vet will approach treatment based on the stage of the condition and if there is an underlying condition. For instance, if there is a nutritional deficiency, adding supplements and making changes to the diet can improve the conditions.

Where there is respiratory distress, the vet will treat with oxygen therapy and an IV to correct fluid imbalances. Diuretics may also be prescribed to reduce fluid build-up. Fluid may also be drained via thoracentesis where a needle is inserted into the chest cavity. There are also a variety of prescription drugs to treat the condition.

Unfortunately, there is no cure and all treatment methods are aimed at slowing the progression of the condition. The grim reality is that this condition is fatal within 6-24 months of diagnosis.

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