Canine Enlarged Heart
Canine enlarged heart, medically known as dilated cardiomyopathy, is the most common cause of canine congestive heart failure, especially in large and giant breed dogs. Dogs with dilated cardiomyopathy usually tire easily and cough (mostly after exercise or at night). Read on and learn more about other symptoms, possible causes, and treatment of dog enlarged heart.

Dilated cardiomyopathy is a disease characterized by an enlargement of the heart chambers. The walls of the heart become thin and balloon out and function poorly. The heart muscle weakens and begins to fail.

Canine enlarged heart is the most common cause of congestive heart failure in large and giant breed dogs.

Dogs that are predisposed to this disease include:

  • Boxers
  • Doberman Pinschers
  • German Shepherds
  • Great Danes
  • American and English Cocker Spaniels
  • Springer Spaniels
  • St. Bernards
  • Schnauzers
  • Old English Sheepdogs

Small and toy breed dogs are rarely affected.

Age-wise, most dogs are around 2 to 5 years of age at the onset of symptoms. Males are more commonly affected than females.

Causes of Canine Enlarged Heart

The exact cause of most cases of dilated cardiomyopathy is not known. In other cases, possible causes include:

  • Hypothyroidism: It has been found that some cases of hypothyroidism in dogs are associated with dilated cardiomyopathy.
  • Myocarditis: Myocarditis is the inflammation of the heart muscle, and this condition sometimes precedes dilated cardiomyopathy.
  • Taurine and/or Carnitine Deficiency: A deficiency of taurine and/or carnitine may lead to canine enlarged heart. This condition is seen in American Cocker Spaniels, Boxers, and possibly Golden Retrievers, Newfoundlands, and others.
  • Genetics: As mentioned above, large and giant breed dogs are genetically predisposed to this disease.

Symptoms of Canine Enlarged Heart

Signs and symptoms of dog enlarged heart are similar to those in canine congestive heart failure and cardiac arrhythmias. They include:

  • Tiring easily
  • Lethargy
  • Exercise intolerance
  • Restlessness
  • Frequent coughing, sometimes bringing up bloody sputum (Coughing usually occurs after physical exertion, and at night time)
  • Appetite loss
  • Weight loss
  • Difficulty breathing; increased panting, wheezing, and puffing
  • Abdominal swelling
  • Rapid and irregular pulse
  • Gray or bluish gums
  • Weakness
  • Fainting with exertion or stress

Diagnosis and Treatment of Canine Enlarged Heart

Diagnosis is based on:

  • Chest X-rays – showing enlarged heart chambers
  • ECG changes – showing cardiac arrhythmias
  • Echocardiogram – showing the characteristic pattern of a failing heart muscle

Treatment includes using medication to:

  • Improve the force of the heart muscle – Drugs such as the digitalis glycosides, angiotensin-converting enzyme (ACE) inhibitors (e.g. Enacard, Fortekor) are commonly used in dogs with dilated cardiomyopathy.
  • Control arrhythmias – A number of drugs, such as digitalis, lidocaine, diltiazem, atropine, and propanalol are used to control arrhythmias in dogs.
  • Prevent fluid buildup in the abdomen and lungs – Diuretics, such as furosemide (Lasix), together with potassium supplements are used.

In addition to medication, dogs with dilated cardiomyopathy are usually put on a low-salt diet.

Certain supplements are also beneficial for dogs with heart problems. These include vitamin-B supplements and taurine and carnitine. Coenzyme Q-10 is another supplement that can help dogs with heart disease.

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