Canine Congestive Heart Failure

Canine congestive heart failure can be caused by numerous canine heart problems such as chronic valvular disease and dilated cardiomyopathy. This page looks at the symptoms and causes of congestive heart failure in dogs.

Congestive heart failure does not equal heart disease. Congestive heart failure is the end result of a weakened heart muscle caused by some form of heart disease.

Specifically, congestive heart failure in dogs is the inability of the heart to pump adequately so that the circulation does not meet the needs of the body. As a result, the health and proper functioning of major organs such as the liver, kidneys, and lungs are greatly compromised, resulting in a problem involving not only the heart but also other major organs.

Unlike heart attacks in people, congestive heart failure in dogs seldom causes the heart to stop functioning all of a sudden. Instead, canine heart failure is a slow process. A weakened heart can continue to function for a long time (months or even years) without showing any sign of failure. Also, unlike heart problems in people in which the build-up of fat is a major cause, heart failure in dogs is seldom caused by fat build-up in their heart.

Causes of Canine Congestive Heart Failure

As mentioned above, canine congestive heart failure is caused by some form of heart disease, which can be congenital or acquired.

Congential heart diseases are the result of a birth defect of the heart. This type of heart diseases is rare and only accounts for about five percent of all canine heart problems.

Acquired heart diseases are those that a dog acquires during his lifetime, which can be the result of injuries, heartworm infestation, bacterial infections, or just normal wear and tear. Certain hormonal problems such as hypothyroidism and Cushing's disease can also cause heart disease in dogs. Certain forms of cancer (e.g. hemangiosarcoma in the heart) can also cause heart failure in dogs.

In small breed dogs, the most common acquired heart disease that causes congestive heart failure is chronic valvular disease with mitral regurgitation. In large breed dogs, it is dilated cardiomyopathy.

As you can see, acquired heart diseases are quite prevalent and, in fact, they account for about 95% of all cases of canine heart diseases.

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Symptoms of Canine Congestive Heart Failure

Signs and symptoms of congestive heart failure in dogs actually depend on the underlying heart problem. However, there are certain common symptoms which indicate that a dog may be suffering from heart failure.

In its early stage, the signs and symptoms are rather nonspecific. They include:

Tiring easily
Exercise intolerance
Restlessness
Coughing (usually occurs after physical exertion, and at night - about 2 hours after the dog goes to bed)

As the heart failure progresses, the dog develops additional symptoms, including:

Appetite loss
Weight loss
Difficulty breathing; increased panting, wheezing, and puffing
Abdominal swelling

In the late stages of canine congestive heart failure, the dog shows the following signs:

Sitting with his elbows spread and his head extended (in order to let more air into the lungs)
Labored breathing
Rapid and irregular pulse
Gray or bluish gums
Fainting with exertion or stress

If the left side of the heart is affected, the dog will cough up a bubbly red fluid (a condition called pulmonary edema).

If the right ventricle is affected, the dog will have a swollen abdomen due to a fluid build-up in the abdominal cavity caused by a backup of blood within the abdominal vessels. This may be accompanied by leg swelling and fluid accumulation in the chest cavity.