Heart murmurs are common findings in dogs and cats, and can be normal or potentially be an indicator for heart disease.
What actually is a heart murmur?
A murmur is a sound heard when the heart is listened to with a stethoscope. Murmurs are created by turbulent blood flow within the heart. Murmurs by themselves do not cause any problems or symptoms for animals.
Murmurs are considered a potential marker for identifying heart disease. However, not all murmurs are due to heart disease, and some heart diseases do not cause murmurs.
Murmurs are most commonly classified into one of three categories:
- Pathologic: A disease or problem with the heart or blood vessels that changes how blood flows within the heart.
- Physiologic: Stress, anxiety, or pain can create or amplify murmurs by making the heart beat harder.
- Viscosity: Changes to how thick or thin blood is, as with anemia, can create murmurs.
Your veterinarian will evaluate your pet and may recommend diagnostic tests to rule out causes other than heart disease. However, if a cause is not found or heart disease is suspected, your veterinarian may recommend a consultation with a veterinary cardiologist to further investigate the cause of the murmur.
How are murmurs categorized?
Murmurs are graded on a 6 point scale, where 1 is quietest and 6 is loudest. Loudness does not necessarily indicate the severity of a problem.
Is there a difference between dogs and cats?
Murmurs in dogs are more likely to represent a heart problem than cats.
Murmurs in cats are less commonly correlated to heart disease. Some studies even say that only 50% of cats with murmurs may have heart disease. Also, some of the more common heart diseases in cats don’t always cause murmurs.
My pet has a murmur! What should I do?
When a murmur is first heard, your veterinarian will make recommendations based upon the murmur’s category, your pet’s age, and the context in which it was heard. Sometimes they will recommend monitoring to see if the murmur persists across multiple visits. Other times your veterinarian may recommend taking chest x-rays or performing other tests.
Chest x-rays are commonly recommended as an initial workup for heart murmurs. Many heart diseases that cause murmurs also can cause changes to the size and shape of the heart over time, which may be seen on x-rays. In patients that are at risk of heart disease, taking x-rays every 6-12 months may be recommended to screen for any changes to the heart.
In animals that are strongly suspected to have active or early heart disease, consultation with a cardiology specialist may be recommended to definitively diagnose the disease process, make treatment recommendations, and establish a prognosis.
An echocardiogram (also called an “echo”) is an ultrasound of the heart, which allows a specialist to see inside the heart. Echocardiograms are typically recommended for pets at heightened risk of having heart disease, or for pets that had significant heart changes on chest x-rays. An echocardiogram is a routine part of consultations with cardiology specialists, and is the best way to diagnose many heart diseases.
If you are concerned or if your pet is showing signs of distress, please visit or call your veterinarian. Nor Cal Veterinary Emergency is available 24/7 to ensure the best health and well-being of your pets.