What is a heart murmur?

Our question this week was:

My Dr. Said my dog has a heart murmur. Dr. Debra –is that serious?


Braddock M. – St. Louis, MO


Hi – thanks for your email. A heart murmur is a sound created by turbulent or disturbed blood flow through the heart or vasculature. They can be heard over any region of the heart and can be associated with a variety of causes. Murmurs can be caused by congenital malformations of the heart, acquired heart disease, or by other diseases that can affect the heart but are not caused by an underlying heart disease.

Murmurs can indicate abnormal heart valve, heart muscle disease, a congenital patency (an abnormal opening) between sides of the heart, anemia, heartworm disease, abnormal thyroid function, or be "functional" which does not indicate heart disease. Some murmurs heard in puppies and kittens will disappear as the pet ages (usually < 4 months).

You asked – is the murmur serious? The only way to know is to know what is causing the murmur. Some underlying causes can be very serious and others may not be serious.

An article that might be helpful to you is Murmurs in Dogs.

Best of luck!

Dr. Debra

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