Enlarged Heart (Dilated Cardiomyopathy) In Dogs: Symptoms, Causes, & Treatments

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Dilated cardiomyopathy in dogs happens when the heart can’t properly contract, which leads to blood backing up in the heart chambers, causing the heart to enlarge.

The blood pushes at the walls of the heart chambers, stretching and thinning them, making it even more difficult for the heart to pump and maintain circulation throughout the body.

All tissues and organs in the body need oxygenated blood to function, especially the lungs and kidneys. Fluid can start to build up in the lungs, and as the enlarged heart gets overloaded, congestive heart failure starts to set in.

In many cases, dilated cardiomyopathy is fatal. If you see the signs of an enlarged heart in your dog, consult your veterinarian right away so you can discuss how to treat and handle the condition. Here’s what you should know about the symptoms, causes, and treatments for an enlarged heart in dogs.

Symptoms Of Enlarged Heart In Dogs

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The symptoms of enlarged heart in dogs can vary depending on how advanced the condition is.

Sometimes vets can miss signs of an enlarged heart if dogs don’t present symptoms or only show mild signs of dilated cardiomyopathy. However, vets can detect many subtle signs during routine physical exams that wouldn’t otherwise be noticeable, so it’s always important to keep up with normal check-ups.

Here are some signs of enlarged heart in dogs:

  • Irregular or weak pulse
  • Muffled breathing or crackling sound while breathing
  • Lethargy
  • Weakness
  • Loss of appetite
  • Weight loss
  • Rapid breathing
  • Shortness of breath
  • Exercise intolerance
  • Coughing
  • Heart murmur
  • Arrhythmia
  • Vomiting
  • Abdominal distension (ascites)
  • Fainting (syncope)
  • Sudden death

Causes Of Enlarged Heart In Dogs

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Vets don’t know the exact cause of enlarged heart in dogs, but there some known factors contribute to the development of the condition.

Nutritional deficiencies, especially carnitine or taurine deficiencies, have been found to contribute to dilated cardiomyopathy in certain breeds.

Other conditions, such as immune mediated abnormalities, infections, genetic disorders, hypothyroidism, and myocarditis have also been linked to dilated cardiomyopathy.

Some breeds have a predisposition to the condition, especially large breeds. These include:

  • American Cocker Spaniels
  • Boxers
  • Dalmatians
  • Doberman Pinschers
  • English Cocker Spaniels
  • German Shepherds
  • Great Danes
  • Irish Wolfhounds
  • Labrador Retrievers
  • Newfoundland Retrievers
  • Saint Bernards
  • Scottish Deerhounds
  • Springer Spaniels
  • Tibetan Terriers
  • Welsh Corgis

Treatments For Enlarged Heart In Dogs

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Treatment for enlarged heart in dogs is often dependent on whether an underlying contributing factor is found. If there is a taurine deficiency, for example, supplements and dietary changes can have benefits for the heart and improve the condition.

Dogs suffering from respiratory distress may need oxygen therapy and intravenous fluids to correct any fluid imbalances. The vet may prescribe diuretics to reduce fluid build-up in the body.

The vet can drain fluid from the chest cavity via a needle in the chest through a process called Thoracocentesis. They may also prescribe various drugs to reduce stress on the heart and improve its function.

There is no cure for dilated cardiomyopathy in dogs, so treatment aims at slowing the progression of the disease. Even with treatment, the condition usually proves fatal within six to 24 months after diagnosis.

If a vet diagnoses your dog with an enlarged heart, then follow their instructions closely and make your dog as comfortable as possible.

Do you keep up with regular vet visits to find and treat medical issues early? How do you keep your dog’s heart healthy? Let us know in the comments below.