What conditions cause heart murmurs in dogs?
There is a wide range of conditions and diseases that can cause a heart murmur in dogs.
Most commonly, heart murmurs in small dogs are caused by a leaky mitral valve (the heart valve in between the left atrium and left ventricle). The mitral valve allows blood to flow from the left atrium to the left ventricle but does not allow for blood to flow back into the left atrium. Sometimes as a dog ages the valve degenerates which causes blood to leak backward. This condition is known as chronic valve disease, degenerative mitral valve disease, or endocardiosis.
In larger breed dogs, heart murmurs are often caused by a disease called dilated cardiomyopathy (with a subsequent leaky mitral valve). Dilated cardiomyopathy is a disease that causes the muscles in the pumping chamber of the heart to become weakened and decrease the contraction strength of the heart.
While these are common culprits of heart murmurs, there is a range of other issues that can cause a murmur to occur. Your vet will be able to run the proper diagnostic tests to properly assess your pets heart and determine the cause of the heart murmur.
What extracardiac problems cause a heart murmur?
Some extracardiac problems can cause what is called a “functional heart murmur.” A functional heart murmur may be due to anemia (low levels of red blood cells), hypoproteinemia (low protein levels in the blood), fever or infection, pregnancy, obesity, or emaciation. With anemia or hypoproteinemia, the blood is too thin or watery, so turbulence is created as it flows through the valves. With young puppies, anemia and/or hypoproteinemia can be caused by a heavy infestation of parasites such as intestinal worms, blood parasites, fleas, or ticks. Adult dogs may become anemic because of blood loss or may have a serious underlying disorder.
How is a heart murmur detected?
In most cases, a heart murmur is detected when your veterinarian listens to your dog’s heart with a stethoscope.
Heart Murmurs in Dogs
If your dog has a heart murmur or other cardiac problems, you may wonder if this is something serious to worry about. What causes heart murmurs and does that mean my pet has heart disease? How does this affect my dog’s life expectancy? The purpose is to check for any abnormal heart rhythms, heart murmurs and other possible.
Oakland Veterinary Referral Services is here to address the issue of heart murmur in dogs, its diagnosis, and treatment.
A heart murmur is not an actual disease or an indication that your dog has heart disease, although it can be a red flag. It is an abnormal sound that occurs during blood flow. It’s a “swooshing” sound that happens between the normal “lub-dub” sounds. The murmur is a vibration or change in a normal heartbeat. It can indicate the presence of a structural abnormality of the heart, or it can point to heart disease. This is why a thorough examination with diagnostic testing is important when your veterinarian identifies a heart murmur.
During an examination, your veterinarian will grade the heart murmur. The grades start at 1, being the faintest murmur, to 6 as the most severe. In other words, the louder the murmur, the higher the grade. While this can give us a better understanding of the severity of the murmur, the grade itself isn’t an indication of whether heart disease is present or not.
There are a few tests recommended for diagnosing the cause of heart murmurs. These include cardiac tests, such as electrocardiogram, blood pressure measurement, ultrasound, and chest X-rays. Along with these, we will look for underlying diseases related to a heart condition, such as anemia, thyroid disease, and an infection, among others. We will also perform a blood test called the Cardiopet ProBNP that can find heart damage or defects by looking for the release of certain hormones.
These tests are necessary to provide the most accurate diagnosis and treatment plan. Low grade heart murmurs with no heart disease or other signs of illness or infection do not need treatment. We do, however, monitor your pet for any changes to the heart and overall health. If the murmur is more severe or there are signs of heart disease, we will advise making changes to your pet’s lifestyle, including weight management, nutrition, and exercise, as well as certain medications.