Heart Murmurs in Dogs

Heart murmurs in dogs may sound alarming, but rest assured they’re not always cause for concern. These murmurs are essentially an extra or unusual sound heard during the heartbeat, often described as a sort of “whooshing” noise. They’re a result of turbulent blood flow within the heart.

If your pup has been diagnosed with a heart murmur, don’t fret! It’s not always cause for concern. Some are ‘innocent’ murmurs, particularly common in puppies, and will usually resolve on their own over time. To ensure the best outcome and monitor your dog’s health, consult with your vet.

What Is A Heart Murmur?

A heart murmur is essentially a sound that your vet hears when listening to your dog’s heart through a stethoscope. Unlike the normal rhythmic “lub-dub” we expect to hear, a murmur can sound like a “whoosh” occurring between the heartbeats.

It’s caused by turbulent blood flow in the heart or nearby vessels.

Now, this might sound scary, but don’t worry! Not all murmurs are a sign of disease. Some are ‘innocent’ and are particularly common in puppies, who often outgrow them without any health complications.

What Is A Heart Murmur

What Are Heart Murmur Grades In Dogs?

Heart murmurs in dogs are typically graded on a scale ranging from 1 to 6, with 1 being the softest and 6 being the loudest. Here’s a rundown of what each grade might indicate:

  • Grade 1: This is the softest murmur and can be quite challenging to hear. It’s often an innocent murmur, particularly in puppies who may outgrow it.
  • Grade 2: This is a quiet murmur that can be heard consistently. Like Grade 1, it’s often a benign murmur in puppies but sometimes can flag a minor issue in older dogs.
  • Grade 3: This murmur is of moderate intensity. It’s often a louder murmur in a specific area of the heart, warranting further investigation.
  • Grade 4: This is a loud murmur. It can be heard on both sides of the chest and flags potential heart disease.
  • Grade 5: This is a very loud murmur that can be felt when you put a hand on the chest. It’s often a sign of significant heart disease.
  • Grade 6: This murmur is so loud that it can be heard with the stethoscope barely touching the chest. It typically indicates severe heart disease.

Remember, it’s essential to consult with your vet if you have concerns about heart murmurs in your pet. They can provide guidance, run necessary tests, and put your mind at ease.

What Are Heart Murmur Grades In Dogs

What Are The Symptoms Of Heart Murmurs In Dogs?

Before diving into the symptoms, it’s important to understand how heart murmurs are diagnosed in dogs. This section will provide you with a brief overview of the diagnostic process.

Remember, only a qualified veterinarian can accurately diagnose a heart murmur in your furry friend. Heart murmurs in dogs can occur due to a variety of reasons. Let’s take a closer look at some of these causes:

Congenital Heart Defects

These are abnormalities in the heart’s structure that your dog is born with. These defects can cause turbulent blood flow, resulting in a murmur.

Congenital Heart Defects

Age-Related Changes

As your dog ages, changes can occur in the heart and blood vessels leading to the development of heart murmurs.

Age-Related Changes

Heart Disease

Underlying heart conditions such as dilated cardiomyopathy or valve disease can also lead to heart murmurs.

Heart Disease


Anemia, or a low red blood cell count, can cause the blood to become thin and create a murmur when flowing through the heart.


Remember, while this list covers some common causes, it’s not exhaustive. Always consult with your vet if your dog develops a heart murmur.

Diagnosis and Treatment of Heart Murmurs in Dogs

If your vet suspects a heart murmur in your dog, they’ll likely recommend additional tests to determine the cause. These tests can include an echocardiogram, chest x-rays, and blood work.


The diagnosis of a heart murmur in dogs involves careful listening with a stethoscope and usually further diagnostic tests. These tests often include an echocardiogram, which is an ultrasound of the heart, and chest X-rays.



The treatment for heart murmurs in dogs will depend on the underlying cause. For innocent heart murmurs, no treatment may be necessary. However, for drones caused by heart disease, medication, lifestyle changes, and in some cases, surgery may be required.

Remember, your vet is your best resource for diagnosing and treating heart murmurs in your dog. Always follow their advice and recommendations for the best possible outcome.

What Conditions Cause Heart Murmurs In Dogs?

Various health conditions can lead to heart murmurs in dogs. Some of these are congenital, meaning your dog was born with them, while others can be acquired over the course of their lifetime.

Understanding these conditions can help you monitor your dog’s health and take timely action if needed.

Heart Valve Disease

Heart valve disease is one of the most common causes of heart murmurs in dogs. As your dog ages, the heart valves can become thickened and degenerate, leading to turbulent blood flow and a heart murmur.

Heartworm Disease

Heartworms are a type of parasite that can live in the heart of your dog. This can cause inflammation and damage to the heart, leading to a heart murmur.

High Blood Pressure

High blood pressure, or hypertension, can cause the heart to work harder, causing a heart murmur.

High Blood Pressure

High Blood Pressure



Although rare in dogs, hyperthyroidism can cause a heart murmur. In this condition, excess thyroid hormone is produced, causing the heart to beat faster.


As mentioned earlier, anemia can cause the blood to become thin, leading to a heart murmur. Causes of anemia in dogs include parasitic infestations, autoimmune diseases, and certain types of cancer.

Remember, if your dog has a heart murmur, it’s crucial to work closely with your vet to determine the cause and the best course of treatment.


What Is The Prognosis Of A Heart Murmur?

The prognosis for dogs with heart murmurs largely depends on the underlying cause. ‘Innocent’ murmurs, common in puppies, generally resolve on their own with no long-term effects.

On the other hand, murmurs caused by significant heart disease or other health conditions may require medical management, and the prognosis would depend on the severity and progression of the disease.

Regular check-ups with your vet are essential to monitor your dog’s heart health and ensure any necessary treatments are administered promptly. Remember, a healthy lifestyle with balanced nutrition and regular exercise plays a crucial role in your dog’s overall well-being.

What Is The Prognosis Of A Heart Murmur

In conclusion

Heart murmurs in dogs are not always a reason for concern, especially if they’re ‘innocent’ murmurs in puppies, which typically resolve themselves over time.

However, they can also be an indicator of underlying health issues, including heart disease, making it crucial to consult with a vet if your dog has been diagnosed with a heart murmur.

With proper diagnosis and timely treatment, dogs with heart murmurs can lead healthy, joyful lives. Remember, maintaining regular vet check-ups, providing a balanced diet, and ensuring your dog gets ample exercise are essential for their overall heart health and well-being.

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