Heart Murmur in Dogs: Causes and Treatment

Heart Murmur in Dogs: Causes and Treatment

A heart murmur can be a frightening diagnosis for dog owners, and may be more common in dogs than you might think. In fact, many dogs are born with heart defects that cause their heart to have a murmur. But what is a heart murmur anyway? And, how will having one affect your dog?

A heart murmur occurs when the usual, rhythmic sound of the heart is altered in some way. Usually, the heart should make a “lub-dub” sound, and heart murmurs make it so that the heart sound is more of a “whooshing” or “swishing” sound. There are many different stages of a heart murmur, with the lower grades usually having a better prognosis than the higher ones.

In this article, we will be explaining everything that dog owners need to know about heart murmurs in dogs. This will include what causes heart murmurs, how they are diagnosed, and if treatment is necessary or available.

What is a Heart Murmur?

A heart murmur occurs when the blood is not flowing through the heart as it should be. This causes the heart to make an abnormal sound when beating.

Usually, this is caused by a heart defect that affects the heart valves or chambers. A hole in the heart could also cause dogs to have a heart murmur. These problems will often be present at birth, and the heart murmur will usually be present throughout the dog’s life.

Occasionally other health issues such as hyperthyroidism could potentially cause a dog to have a heart murmur in adulthood. However, this is rare.

Are There Different Kinds of Heart Murmurs in Dogs?

There are six different grades of heart murmur in dogs, with grade 1 being the least severe and grade 6 being the most severe. Here we will be explaining what each grade of heart murmur looks like and what it means for your dog. Keep in mind that “grading” is often subjective, and it is sometimes helpful to think of them as “soft, moderate, loud, or palpable”.

Grade 1 Heart Murmur

This is the least serious grade of heart murmur, and it requires careful listening and a very quiet room for the vet to hear it. As long as your dog does not have a heart condition affecting their health and this was a born defect, it is not likely to affect your dog. Your vet will likely recommend some careful monitoring to ensure that it doesn’t get worse throughout your dog’s life.

Grade 2 Heart Murmur

Grade 2 heart murmurs are also generally not serious, but it is easier for a vet to hear with a stethoscope. Still, this stage usually just requires careful monitoring to ensure that the heart murmur doesn’t get worse.

Grade 3 Heart Murmur

A grade 3 heart murmur is characterized by moderate-to-loud murmur sound, but one that is only present on one side of the chest. Grade 3 heart murmurs are more severe than grades 1 and 2, but they are often still manageable. Heart murmurs causing severe problems in dogs will likely be at least stage 3.

Grade 4 Heart Murmur

A grade 4 heart murmur is a loud murmur like stage 3, but in stage 4 the murmur is heard on both sides of the chest. This is typically more serious than stage 3.

Grade 5 Heart Murmur

Grade 5 heart murmurs are very loud and are heard on both sides of the chest. This stage is also characterized by being able to feel the heart murmur by placing a hand on the chest. A grade 5 is typically considered severe.

Grade 6 Heart Murmur

A grade 6 heart murmur is the most severe, and it can be both heard and felt without the use of stethoscopes. It is often so severe that it can be heard with a stethoscope placed an inch or two away from the chest. This stage of heart murmur is usually caused by a very severe heart defect or a disease-causing heart problems such as advanced heartworm disease.

What are the Signs of Heart Murmur in Dogs

Most dog owners with dogs that have stage 1 or 2 heart murmurs will not know until their vet listens to their heart. However, more serious stages could bring along with it other signs and symptoms. Here are some signs of heart murmur in dogs to look out for.

  • Coughing and continuous heavy breathing
  • Unexplained weight loss
  • Suddenly collapsing or fainting
  • Very pale gums or blue gums (a sign of an emergency)
  • Poor growth in puppies
  • Suddenly being unable to exercise

If you notice any of the above symptoms in your dog it is recommended that you take them to the vet for treatment as soon as possible.

How is a Heart Murmur in Dogs Diagnosed?

Most heart murmurs in dogs are simply diagnosed by a vet listening to their heart with a stethoscope. However, once a heart murmur is detected your vet will likely want to do further testing to discover the cause of the murmur. This testing is usually done by a veterinary cardiologist.

dog heart murmur in Silver Spring, MD

Can Heart Murmur in Dogs be Treated?

Heart murmurs cannot themselves be treated. However, your vet will work to treat any cause of the heart murmur. As a result, treatment will vary depending on the cause of the heart murmur.

How Serious is a Heart Murmur for a Dog?

The answer to this question depends entirely on what stage of heart murmur your dog was diagnosed with. Stage 1 and 2 heart murmurs are usually not very serious. However, stage 3 heart murmurs and beyond are typically a concern. Take your dog to the vet as soon as possible if you suspect that her or she may have a heart murmur.

Is it OK to Walk a Dog with a Heart Murmur?

Dogs with heart murmurs are often somewhat sensitive to exercise and tire more quickly than other dogs. It is always best to consult your vet about how much exercise your dog can handle when they have a heart murmur.

Dog Heart Murmurs in Silver Spring, MD

If you have noticed your dog may be showing signs of a heart murmur in Silver Spring, MD, contact Apex Vets. Our veterinarians will be able to listen to your dog’s heart and see if a heart murmur may be the cause of your pet’s symptoms. Contact us today.