Dilated Cardiomyopathy (DCM) in Cats

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Overview of Dilated Cardiomyopathy in Cats (DCM)

Dilated cardiomyopathy (DCM) is a disease characterized by dilation or enlargement of the heart chambers and markedly reduced contraction. The left ventricle is most always involved. Advanced cases demonstrate dilation of all cardiac chambers.

Below is an overview of Dilated Cardiomyopathy in Cats (DCM) followed by in-depth information on the diagnosis and treatment of this feline heart disease.  

DCM in cats is now comparably rare. In the past, feline dilated cardiomyopathy was due to dietary deficiency in the amino acid taurine and commonly affected breeds such as Burmese, Abyssinian, Siamese and domestic mixed breed cats. Today, reputable cat food companies assure their products are well supplemented with taurine, an essential dietary amino acid for cats.

DCM can occur in cats of any age – from 2 to 20 years. The mean age of onset is approximately 10 years. It appears to be more common in male cats.

Occasional cases of idiopathic DCM, which is cardiomyopathy of unknown cause, are observed in cats. Clinical signs include CHF and development of blood clots (thromboembolism) that obstruct blood flow to one or more legs.

DCM is very serious and the mortality rate, even of treated cases, is very high.

What to Watch For

  • Shortness of breath
  • Coughing (uncommon in cats)
  • Exercise intolerance
  • Collapse
  • Sudden onset of pain and paralysis, usually in the back legs
  • Abdominal distension
  • Lethargy
  • Loss of appetite

    The advent of these problems should alert you that a serious emergency is at hand.

  • Diagnosis of Dilated Cardiomyopathy in Cats 

    Diagnostic tests are needed to recognize dilated cardiomyopathy and exclude all other diseases. Tests may include:

  • Complete medical history and physical examination including auscultation of the heart and lungs
  • Thoracic radiographs (chest X-rays)
  • An electrocardiogram (EKG)
  • Arterial blood pressure
  • Packed cell volume test or a complete blood count (CBC)
  • Serum biochemistries, which are blood tests that are especially important if there is heart failure, thromboembolism or complications in other organs
  • Echocardiogram (ultrasound of the heart) to establish the diagnosis and may require referral
  • Serum thyroxine (thyroid) test for cats greater than 7 years of age
  • Whole blood taurine test in cats with DCM
  • Treatment of Dilated Cardiomyopathy in Cats (DCM)

  • In advanced cases leading to congestive heart failure, drug therapy with a diuretic, angiotensin converting enzyme inhibitor (such as enalapril or benazepril) and/or digoxin is prescribed. Additional drugs may be added such as the diuretic/hormone antagonist, spironolactone.
  • The diet is changed to reduce sodium intake.
  • Nutriceuticals such as taurine pills or L-carnitine are recommended in very specific instances.
  • In cases of “arrhythmogenic” dilated cardiomyopathy, drugs that regulate the electrical heart rhythm are indicated.
  • In cats with or at risk for thromboembolism, special treatments (anticoagulants) are needed.
  • Home Care and Prevention

    Administer any veterinary prescribed medications. Watch for difficulty in breathing, increase in coughing, lethargy or sudden inability to use one or more limbs. Observe the breathing rate when your pet is relaxing. Changes in attitude and appetite are often signs of problems in cats.

    Schedule regular veterinary visits to monitor the condition.

    Dilated cardiomyopathy in cats can be caused by taurine deficiency. This is often associated with exclusive feeding of a single (off brand or “special” brand) canine or human diet. Feed a balanced, high-quality cat food that is supplemented with taurine.

    In-depth Information on Dilated Cardiomyopathy in Cats (DCM)

    Related Symptoms or Diseases

    DCM is thought to be the result of diverse processes that affect heart muscle cell function.

    Causes may include:

  • Deficiency of metabolic substrates (e.g. taurine)
  • Idiopathic (occurring without known cause)
  • Myocarditis (inflammation of the myocardium)
  • Severe global myocardial ischemia (lack of blood supply to the heart)
  • Toxic injury to the heart muscle cells that can be caused by some drugs (e.g. doxorubicin, potassium iodide toxicity)
  • Hyperthyroidism (chronic excess of thyroid hormone)
  • Persistently abnormal heart rhythms such as sustained ventricular or supraventricular tachycardia (reversible after some weeks if rhythm is controlled)
  • Chronic hypokalemia (low blood potassium) which may act by causing taurine deficiency in cats

    The vast majority of cases of DCM are idiopathic and probably predisposed by genetic factors. Most reported cases of DCM in the cat have developed secondary to taurine deficiency, but current cases are usually unresponsive to taurine supplementation, indicating there is another reason for cases.

    A number of other diseases can be easily confused with dilated cardiomyopathy unless an appropriate diagnostic evaluation is completed. Diagnostic tests should help exclude the following conditions from consideration:

  • Congenital heart disease (birth defects)
  • Feline hypertrophic cardiomyopathy (genetically programmed thickening of the heart muscle)
  • Hyperthyroid heart disease in cats from thyroid tumors
  • Feline restrictive cardiomyopathy (scarring or fibrosis of the heart muscle in cats)
  • Hypertensive heart disease (heart enlargement from high blood pressure)
  • Pericardial diseases, which affects the lining around the heart
  • Mediastinal masses (tumors in the front part of the chest cavity)
  • Myocarditis (inflammation of the heart muscle most difficult to diagnose)
  • Moderate to severe anemia, which can cause heart failure, especially in cats
  • Heartworm disease
  • Fever, which can cause heart murmurs
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