Hearing that your pooch has a heart murmur can be very worrying for any owner, but often this can be caused by a lack of understanding around exactly what a heart murmur in dogs is.

Murmurs can be a common condition and are much like fevers – while most heart murmurs aren’t serious and won’t require any further treatment, they can also be an indication of an underlying health issue.

Heart Murmur In Dogs: Everything You Need To Know

It’s therefore useful to gain a complete understanding of what they are so you know what to do if you suspect your pet is suffering from this soft tissue condition.

In this guide, we will explain what a heart murmur is, the different types of heart murmurs, the causes, and treatment of them, what you should do if you’re concerned, as well as some other commonly asked questions.

What is a heart murmur in dogs?

Dog’s hearts aren’t too dissimilar from ours in the sense that they pump blood around their body and they too can run into complications, however innocent they might be.

A heart murmur is simply an extra or unusual sound produced by a squirt of blood inside the heart when it pumps. This in turn creates an audible noise known as a ‘murmur’. They can also be found in humans too, with children being the most commonly affected.

While some can be completely innocent, heart murmurs can be serious and may be a sign of something more sinister going on in your dog’s heart.

Types of heart murmurs

Veterinarians have classified heart murmurs into three categories, the variable factor between the three being the timing of which they occur.

The three types of heart murmurs in adult or older dogs are:

  • Systolic murmur: occurs during heart contraction
  • Diastolic murmur: occurs during the relaxation between beats
  • Continuous murmur: occurs continuously throughout the cardiac cycle

Heart murmur grades in dogs

While some heart murmurs are barely detectable, others may be more prominent which can be extremely distressing for dog owners.


Heart Murmur In Dogs: Everything You Need To Know

To aid vets in determining the cause of heart murmurs in dogs, a grading system is used which ranks murmurs from 1-6 depending on how loud they are using a stethoscope.

The grading system is as follows:

  • Grade 1 heart murmur in dogs: these are considered the least serious. They are very soft in sound and barely audible
  • Grade 2 heart murmur in dogs: a soft sound heard by using a stethoscope
  • Grade 3 heart murmur in dogs: mid-way in loudness and can be heard in more than one specific location
  • Grade 4 heart murmur in dogs: these murmurs are moderate to intense and can be heard on each side of the chest
  • Grade 5 heart murmur in dogs: very loud and can be heard even when the stethoscope is barely touching the chest. They can also be felt by holding a hand against the chest
  • Grade 6 heart murmur in dogs: these murmurs are also very loud and can be felt by touching the chest; they are also the most severe

What is the cause of heart murmurs in dogs?

Heart murmurs in dogs are caused by the following:

  • A disturbance in the blood flow is associated with high flow through normal or abnormal heart valves and heart chambers or with structures vibrating in the blood flow
  • Flow disturbances associated with outflow obstruction or forward flow through diseased valves or into a dilated great vessel
  • Flow disturbances associated with regurgitant flow due to an incompetent valve, patent ductus arteriosus, or a defect in the septum (the wall that separates the heart’s left and right sides)

It’s also important to note that a number of different diseases could also result in your dog having a heart murmur, so it’s best to consult with your vet if you have any concerns.

What are the signs and symptoms of heart murmur in dogs?

Heart murmurs can be a sign of an underlying heart condition and it’s important they are detected as early as possible. One direct link heart murmurs have with the disease is heart disease.

Heart Murmur In Dogs: Everything You Need To Know

If you see the signs of heart problems or heart disease as well as a heart murmur, contact your vet immediately.

Here are a few signs of heart disease that may appear along with a heart murmur:

  • Exercise intolerance
  • Lethargy or weakness
  • Panting, coughing, or difficulty breathing
  • Pale gums or mucus
  • Distended abdomen or bloated appearance
  • Fainting or collapse

How are heart murmurs diagnosed?

As murmurs are often able to be heard by listening to the chest, the most common method of diagnosing this is by using a stethoscope.

With this device, the vet will be able to listen to your dog’s heart, determine how loud it is and where abnormal heart sounds are located. This enables the vet to determine the type of murmur and its grade.

If the vet is unable to identify this or has any further concerns, they can use additional advanced imaging tools and tests such as chest x rays, radiographs, echocardiograms, and electrocardiograms to identify the underlying cause.

What is the treatment for heart murmurs in dogs?

Heart murmurs themselves aren’t treatable, but what is treatable are the symptoms and problems that arise from them.

In most cases, heart murmurs are usually a result of an underlying health condition. Therefore, any treatment your dog receives will be dependent on the issue at hand.

Heart Murmur In Dogs: Everything You Need To Know


However, some good news is that many of the causes of heart murmur in dogs are treatable, so it really is important that any concerns have been raised with your vet as soon as possible.

What should you do if you suspect your pet has a heart murmur?

Despite the serious nature of heart murmurs in dogs, there really is no need to panic. Heart murmurs are easily diagnosed which can only be a good thing for your pet.

If you have any concerns regarding the health of your dog, please get in touch with your vet as soon as possible.

If you need some further advice or information around heart murmurs in dogs then please don’t hesitate to contact us.