Australian Shepherd Health & Genetics Institute

Australian Shepherd Health & Genetics Institute

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Dilated Cardiomyopathy


What is dilated cardiomyopathy (DCM)?

Cardiomyopathy is an inflammation of the heart muscle.  Dogs with DCM have an enlarged heart with oversized chambers and thin walls.  The damaged heart is unable to pump blood effectively.  Usually only one side of the heart is affected, most frequently the left.  DCM can be secondary to taurine deficiency, myocarditis, low blood potassium, abnormal heart rhythms, global myocardial ischemia, and as a toxic side effect of some drugs.  The majority of cases, however, are of unknown origin.  It can cause sudden death in an apparently healthy dog.

The sudden, unexpected death may be a sign of DCM but it can also mean the dog had hemangiosarcoma; a rupture of a blood vessel weakened by this cancer can lead to catastrophic internal bleeding.  An autopsy woud be necessary to determine the cause.

How do I know if my dog has DCM?

Your dog may pant excessively, have shortness of breath, cough, be lethargic or intolerant of exercise, anorexia, show reluctance to lie down, not be able to rest comfortably, or collapse.  A vet will do an exam and various tests to rule out other types of heart disease.  An echocardiogram will be used to confirm diagnosis of DCM.  If an Aussie dies suddenly and DCM is being considered, hemangiosarcoma should be ruled out.

What does having DCM mean for my dog?

Age of onset is usually 4-10 years of age but sometimes occurs earlier.  There is no cure for DCM but the dog can be treated with medication and nutritional supplements to delay onset of heart failure.  DCM will eventually prove fatal.

Is DMC common in Aussies?

DCM is very rare in Aussies. .

Is DCM inherited in Aussies?

Probably not.  However, if more than one member of a family has been diagnosed with DCM and hemangiosarcoma has been ruled out in each case it would be best to assume inheritance.

What does DCM mean for my breeding program?

In the case of multiple affected dogs in a family, don’t repeat the crosses that produced it, breed parents and full and half siblings away from the affected pedigrees and only to mates with no family history of DCM.

Is DCM inherited?

Yes, but it is very rare in Aussies.

Is there a DNA test?

Yes, but it is a risk factor gene so having the mutation (one or two copies) means the dog could have DCM but it does not mean it will.  This mutation  has been found in Aussies but since the disease is so rare the level of risk for our breed is low.  The test would be most useful to screen breeding relatives of an affected dog so breeders can select clear –tested mates to eliminate the gene from their lines without discarding  healthy dogs.