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

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Dilated cardiomyopathy in dogs happens when the heart is enlarged due to an inability to properly contract, which causes blood to back up in the heart chambers. The blood pushes at the walls of the heart chambers, stretching and thinning them, which makes 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, it is important that you consult your veterinarian right away so you can discuss how to treat and handle the condition. Here is 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 an enlarged heart in dogs can vary depending on how advanced the condition is. Sometimes veterinarians can miss the signs of an enlarged heart if dogs do not present symptoms or only show mild signs of dilated cardiomyopathy. However, many subtle signs can be detected during a routine physical examination that wouldn’t otherwise be noticeable, so it is always important to keep up with normal check-ups. Here are some signs of an 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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The exact causes of an enlarged heart in dogs is not known, but there are some factors that contribute to the development of the condition. Nutritional deficiencies, especially carnitine or taurine deficiencies, have been found to contribute to the development of 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 are predisposed 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 Retrieverss, Saint Bernards, Scottish Deerhounds, Springer Spaniels, Tibetan Terriers, and Welsh Corgis.

Treatments For Enlarged Heart In Dogs

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Treatment for an 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 be given oxygen therapy and intravenous fluids, if necessary, to correct any fluid imbalances. Diuretics may be prescribed to reduce fluid build-up in the body. Thoracocentesis is a process by which fluid can be drained from the chest cavity via a needle in the chest. Various drugs may be prescribed to reduce stress on the heart and improve its function.

It is important to note that there is no cure for dilated cardiomyopathy in dogs, so treatment is aimed at slowing the progression of the disease. Even with treatment, the condition is usually fatal within 6 to 24 months after diagnosis. If your dog is diagnosed with an enlarged heart, follow veterinary instructions closely and make sure your dog is as comfortable as possible.