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.
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
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
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.
