Question

My 11-month old puppy has a heart murmur. What is a heart murmur and how will it affect him over his lifetime?

Answer

A murmur is what we hear when listening to a heart that has some turbulence in the blood flow. Normally the blood flows through the heart very smoothly and makes little or no noise. When something alters this smooth flow, turbulence results and this is heard as a “whooshing” noise that is called a murmur.

Heart murmurs have a number of causes. Most are the result of a faulty heart valve (either too tight or too loose). The most common cause of murmurs in large dogs is an aortic stenosis, which is a narrowing of the valve in the left ventricle (chamber) of the heart. Other malformations of heart valves or problems with the heart wall could also lead to a murmur.

Because there are many different causes of murmurs, it is hard to say how it will affect your dog without conducting some tests. Your veterinarian may wish to take x-rays and an ultrasound to determine the underlying cause of your dog’s heart murmur. Please consult your veterinarian for more information.

This question was answered by Dr. Robert J. Krapfl, director of Gentle Doctor Animal Hospital in Omaha, Nebraska.