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Dilated Cardiomyopathy in Dogs

Posted October 24, 2011 in Dog Diseases & Conditions A-Z

Heart disease is as scary in dogs as it is in humans. Dilated cardiomyopathy (DCM) is a serious condition of the heart that occurs when the heart muscle becomes diseased and weak. The heart is a muscular pump that pushes blood around the entire body. In the normal dog, it beats approximately 180,000 times a day! A muscle working that hard needs to be in shape, with good muscle tone, to do its job effectively. When DCM strikes it renders the heart muscle weak and flabby; therefore, the heart starts to fail at its job. 

 The heart has four chambers. Like many mechanical pumps, the heart has two functional parts. The atria, seen above as thin-walled chambers labeled “left atrium” and “right atrium,” act as pump primers. Blood returning to the heart is held here and when the atria are full, they contract, pushing blood into the pumping chambers or ventricles. When full, these pumping chambers contract forcefully, pushing blood out to all the blood vessels in the body.

You’ll see that the heart is actually made up of two pumps, a right and a left one, based on their anatomic position in the body. So we have one pump made up of the right atrium and right ventricle and one made up of the left atrium and left ventricle. Valves between the atrium and the ventricle ensure blood always moves in one direction, from the atrium into the ventricle.

When dilated cardiomyopathy strikes these chambers, all enlarge because the heart muscle becomes weak and stretched. Blood is still pumped, but not effectively. Limb muscles and organs within your dog’s bodies need a constant and consistent blood supply to work properly. Ineffective circulation will cause muscles to become weak and organs to malfunction. This will result in some of the symptoms we discuss next. Additional symptoms are caused because fluid will leak from the blood when it isn’t pumped effectively. As a consequence, we see abnormal fluid accumulations on top of muscle and organ dysfunction. That’s why swollen ankles are a common sign of heart problems in people. You won’t see swollen ankles in your dog, but your veterinarian might see fluid leaking into the lungs, which causes breathlessness and coughing.


Breeds commonly affected by DCM include:

Your dog’s body has some protective mechanisms

Related symptoms: 

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