Ask the Vet

You’re at the vet with your dog and the doctor tells you that they hear a “murmur”. What does this mean? A murmur is abnormal sound that the veterinarian hears when listening to the heart with a stethoscope. As murmurs can have serious consequences, a complete heart work up is recommended when one is detected.

Your vet will begin the physical exam by assessing the “grade” of the murmur. Your dog’s murmur will be assigned a grade on a scale of 1 – 6 out of 6. Your vet will record that number and continue to examine your dog for other symptoms, such as, abnormal sounds in the lungs, poor pulses in the hind legs or fluid in the abdomen. As these are symptoms that can accompany heart failure, your vet will perform blood work to rule out some of the common causes of murmurs and heart issues such as heartworm disease and anemia. Blood work will also indicate whether or not there are secondary problems such as kidney changes, or electrolyte imbalances. Next, x-rays of the chest and lungs (sometimes abdomen) are usually taken to assess heart size and whether there is fluid accumulating in the lungs. Your vet may feel your dog requires additional tests such as an electrocardiogram or an echocardiogram. An electrocardiogram records the electrical activity of the heart. An echocardiogram is a special ultrasound of the heart itself. Both tests are helpful in determining how efficiently the heart is beating and what secondary changes that a murmur may have created. If your vet is unable to perform these tests, you may be referred to a specialist who can.

When we adopted our Boxer Cassidy, she had a very evident murmur that had persisted since she was tiny puppy. We followed up with the recommendation to have a veterinary cardiologist examine her at regular intervals. At about 18 months old she got a clean bill of “heart health” even though her murmur still persists. Cassidy has a condition known as Aortic Stenosis which means that there is some obstruction of blood flow from one chamber of her heart (ventricle) into the large artery of the body (aorta). The murmur is a result of the interruption in blood flow. The specialist feels that since Cassidy’s heart is showing no signs of any compromise, we don’t have to worry too much about her heart or put her on medications.

Not all dogs with heart murmurs are as lucky as Cassidy. There are many that have additional changes to their bodies when their hearts can’t pump blood efficiently. These changes are what we call “heart failure”. One frequently seen change is the accumulation of fluid around the lungs. This usually produces the typical unproductive cough that is heard in most dogs with heart disease. Some dogs will have fluid accumulate in their abdomen rather than their chest and may take on a pot-bellied appearance. Still others may have very extreme changes like fainting episodes or weakness to their hind end and drag their back legs. In some cases, dogs may show no signs at all and simply fall over dead due to a heart condition that no one knew about.

Since a murmur can have serious consequences it’s important to discuss all the options with your veterinarian and come up with the best plan for your best friend.