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Published: May 10, 2012

Heart murmurs in dogs are a common issue with a wide variety of causes. Due to the nature of this problem, a dog diagnosed with a heart murmur may be completely fine, or the condition could cause serious health complications or even death.  Because of the issues associated with heart murmurs, pet owners should be sure to bring their canines to the veterinarian regularly so this issue can be detected and treated.

Veterinarians detect a heart murmur by listening to the dog's heart with a stethoscope. The term "murmur" simply refers to an abnormal sound. Heart murmurs are graded on a scale of one to six depending on how severe they are. Murmurs graded at three or above are more often related to a more serious issue, such as heart disease.

The most common type of heart murmur is found in puppies, especially large breeds, as they begin to grow. Heart murmurs of this nature are referred to as innocent, or physiologic. This means that they will not cause any issues for the dog, and the murmur will disappear as the puppy grows.  Unfortunately, more serious types of murmurs exist in puppies as well. These can be caused by a genetic defect in the dog - the heart or valves may develop abnormally and this sort of problem does not disappear over time.  Your veterinarian can detect a heart murmur during the puppy's check-up and any necessary follow-up will be recommended at that time.

Heart murmurs are commonly found in older dogs and are most often caused by degenerative heart disease or other problems related to blood flow.  An older dog with a heart murmur  caused by heart disease may exhibit decreased appetite, weight loss, coughing or difficulty breathing. If you've noticed any of these clinical signs, VCA Animal Hospitals recommends taking the dog to a veterinarian for a diagnosis.

Treatment for a dog with a heart murmur will depend on what the underlying heart problem is.  In some cases of congenital heart disease in young dogs, the condition and the murmur can be corrected with surgery.  In older dogs with degenerative forms of heart disease, the condition may be manageable with medication.  The prognosis for a dog with a heart murmur depends on the severity of the underlying disease and whether or not heart failure is present.