Chris Paquette, CVT
Port City Referral Hospital - Proud Supporter of Project Pawsitive
So, you have just taken your dog to your veterinarian for the annual wellness examination, or you just adopted a puppy and are bringing her in for her first veterinary visit, or perhaps your faithful companion of many years has seemed less energetic lately and you just want to make sure everything is all right. As part of a thorough examination, your veterinarian will listen to your dogs’ heart. This will give your veterinarian more information than you know. They listen to the heart rate, rhythm, and to see if they can hear a heart murmur. Then it happens; you are told that your dog has a murmur. You wonder, what is a murmur? Is it serious? What should I do next, and how is it treated? So, first things first, what is a heart murmur?
What is it?
A heart murmur is a sound caused by turbulent blood flow. It is just that, a sound. A murmur is not a disease, though it may or may not indicate that a disease process is present. The sound may be generated from any of the four valves present in every mammalian heart, or by other open communications in the heart or connected great vessels of the heart, that have failed to close during fetal development or shortly after birth. Murmurs can also have extra-cardiac
causes such as anemia. The causes of a heart murmur may be acquired, congenital or a transient “innocent” murmur that may go away on its own in puppies. Since the murmur is only a sound, it is not something that is directly treated. However, it may represent a disease process that needs, or will eventually need treatment.
Finding the Cause
If your dog is an adult and the murmur is a new finding, your veterinarian may refer you to a cardiologist for an echo-cardiogram. This is an ultrasound of the heart and will give your veterinarian all the information necessary to know exactly what the murmur is being caused by, and if it represents a disease process requiring treatment. The echo-cardiogram is the only test available that will yield this information. If your dog is a puppy and otherwise thriving, your veterinarian may choose to wait until the next visit to see if the murmur is still present before recommending a visit with the cardiologist.
Now that you have a basic overview of heart murmurs the last thing we will touch on, is when you the owner need to be concerned. For older dogs with
with a new murmur some signs to watch for and notify your veterinarian of if you see them are, coughing, exercise intolerance, or any episode of collapsing/fainting. An early indicator of a problem for adult dogs is having a resting respiratory (breathing) rate of over thirty breaths per minute. You can calculate this by counting the rise and fall of the rib cage while they are sleeping. One rise and fall is one respiratory cycle (one breath). You should take the rate when your dog is asleep to get the most useful information. A rate above thirty breaths per minute is a sign that you should go to see your veterinarian for a referral to the cardiologist. For puppies, all of the above signs hold true with the addition of being generally less active than other puppies of the same breed.
The disease processes that cause murmurs can be serious, and are treated in different ways. Sometimes the defects can be fixed with surgical or catheter-based physical interventions. While other times the disease processes are managed with pharmaceutical interventions. Ignoring a murmur for an extended period of time could lead to complications such as congestive heart failure, but not all murmurs develop into a condition requiring treatment.
In conclusion, heart murmurs should be taken seriously and investigated, but until the cause is determined, there is no reason to panic. Even in the case that the murmur is caused by heart disease your dog’s condition may be managed by a cardiologist and it may still live a happy full life. **