Heart Murmur in Dog

Is your dog diagnosed with Heart Murmur?First of all, stop panicking, and secondly, stop visiting tons of website pages to find out what to do!
I know, it’s so scary to hear that your small fluffy friend has been diagnosed with a heart murmur. But don’t worry much as it’s a pretty common thing in dogs.

Do you know that Heart murmurs affect around 60% of dogs over the age of 5 years old? And thousands of people often search for “dog congestive heart failure when to put down” in Google! 

Any type of health issue may be diagnosed anytime during your pet’s lifetime, and even some puppies are born with some serious problems. However, some illnesses are known, while others may leave you with more questions. And of those illnesses is Heart murmur! 
So, after your recent visit to the vet, your dog has been suffering from a heart murmur, which can leave you puzzled and scared with a lot of questions. 

Just keep reading on! 

Today in this blog, we’re going to tell you everything about heart murmur in dogs. We’ve covered everything from the murmur definition, types of heart murmur and dog heart murmur symptoms to its causes and treatment. heart murmer.
So keep reading till the end and get all the right information to keep your dog healthy and happy!   
Let’s begin. 

What is a Heart Murmur?

What is a Heart Murmur

A heart murmur is an abnormal heart sound or vibration caused by disturbed blood flow inside the dog’s heart.

This rhythmical lub-dub or whooshing noise can be heard through a stethoscope. The turbulent flow of the blood is the main reason behind this audible sound. When the blood flows fast through the abnormal heart valves or across abnormal structures within the heart, you can hear and feel this sound (a swoosh noise – swoosh-dub, swoosh-swoos) when you lay your hand over your dog’s heart. 

So you might be wondering, what’s the big deal with this sound? Does it affect your dog’s health much?

The answer is yes! That’s because sound is actually a major symptom of another underlying medical problem. 

How To Identify a Heart Murmur in Dogs?   

The vet finds heart murmurs by listening to your pet’s heart with a stethoscope. Sometimes an echocardiogram (ultrasound of the heart), which is a type of non-invasive test, is performed to find the real cause of the murmur. 

Your veterinarian will listen for:  

  • Loudness – This is determined by the amount of turbulence taking place in the dog’s heart.  
  • Location – Exactly where the murmur can be heard the loudest. 
  • Timing – It’s important to determine the right timing when the murmur happens. 
  • Length – This will determine how long the murmur lasts through the heart cycle.

Types of Heart Murmur in Dogs

On the basis of the sound which is heard during the heart cycle, Veterinarians has classified heart murmur into three categories:  

  • Systolic murmur – this occurs when the heart contracts
  • Diastolic – occurs in between beats
  • Continuous – occurs throughout

Systolic heart murmurs occur during the systole phase, and this is the one that most canines suffer through. On the other hand, Diastolic murmurs are rarely found in dogs. Continuous murmurs, which are also known as to-and-fro murmurs, generally happen throughout the regular cardiac cycle of a dog’s heart.

Grading Scale for Heart Murmurs in Dogs

Now you know that not every heart murmur is the same as they sound differently. They can be different by intensity and loudness, which is generally determined by the amount of disturbance present in the heart. Here are some ways to help a dog suffering from chronic boredom that you must know. 

So, when to worry about a heart murmur? 

Veterinarians grade the heart murmurs in Dogs on a scale of 1 (mild) to 6 (severe). Here’s the murmur grading:

  • Grade 1: Barely audible 

This is the least serious type of heart murmur, which is also the least audible. 

  • Grade 2: Soft murmur 

This is soft and quiet but can be heard with a stethoscope

  • Grade 3: Intermediate loudness

This grade of heart murmur has an intermediate volume that is consistently heard. This is a symptom of serious health problems.  

  • Grade 4: Loud murmur

This murmur can easily be heard on either side of the dog’s chest.

  • Grade 5: Very loud murmur

A heart murmur of this grade can easily be heard with a stethoscope or felt by placing your hand on the chest. 

  • Grade 6: Very loud murmur 

You can feel this murmur when you place your hand on the dog’s chest, and this is the most severe type of heart murmur.

Configurations for Heart Murmurs in Dogs

Configurations for Heart Murmurs in Dogs

The heart murmur configuration, also known as the quality of the murmur, is basically the way of murmur sounds. Veterinarians describe four types of heart murmur configurations: 

  • Plateau murmurs
  • Crescendo-decrescendo heart murmurs
  • Decrescendo heart murmurs
  • Continuous murmurs (machinery quality murmurs)

Symptoms of Heart Murmurs in Dogs

Now you know what a heart murmur is, its types, and grading with configuration, let’s move on to the heart murmur symptoms in dogs.

Surprisingly, most canines don’t show any signs of illness, whereas some show.

Some of the most common symptoms of heart murmur include: 

  • Irregular heartbeat
  • Weakness or lethargy
  • Hacking, persistent cough
  • Excessive panting even when resting
  • Tires easily
  • Lack of energy
  • Distended abdomen or bloated appearance
  • Collapses or faints
  • Gums and/or tongue are bluish in color
  • Racing pulse
  • Pale gums or mucus
  • Lack of appetite
  • Severe water retention


The above symptoms are seen in adult dogs. Whereas in puppies, you can determine these health issues by noticing their growth. A puppy suffering from a heart murmur will be thinner and smaller than other pups their age.  

Causes of a Heart Murmur in Dogs

The basic cause of a heart murmur varies. For example, it can be caused by either actual damage to the heart or medical conditions that are not even related to the heart.

On that basis, murmurs are determined as “innocent” or “physiologic” and sometimes pathologic as they occur because of some structural problem within the heart (cardiac disease). 

Heart murmurs can also be caused by the dog congestive heart failure or abnormal stretching of the heart muscle, faulty valves, narrowing of the veins or arteries, dilated heart chambers, holes in the heart walls, tumors, other structural abnormalities. These all things create blood turbulence which results in a heart murmur. Here you can also read about Melatonin for Dogs

However, suppose a murmur is caused by a medical condition that is not related to the heart. In that case, they’re usually quiet and intermittent, and this can easily be resolved after getting the right treatment.

Here is a list of conditions that can cause heart murmur in dogs:

  • Anemia
  • Atherosclerosis
  • Cardiomyopathy
  • Dysplasia
  • Endocarditis
  • Endocardiosis
  • Heartworm disease
  • Hyperthyroidism
  • Pulmonic stenosis
  • Other valvular stenosis
  • Tumors
  • Tetralogy of Fallot

Continuous or To-and-Fro Heart Murmurs

The following reasons cause this type of heart murmur:

  • Patent ductus arteriosus
  • Ventricular septal defect with aortic regurgitation
  • Aortic stenosis with aortic regurgitation

Diastolic Heart Murmurs

The following medical conditions cause this type of heart murmur:

  • Mitral and tricuspid valve stenosis
  • Aortic and pulmonic valve endocarditis (inflammation of the inner layer of the heart)

Heart Murmur in Dogs: Treatment & Investigations

Heart Murmur in Dogs: Treatment & Investigations

See, Vets do not treat the heart murmurs in dogs directly! The proper treatment depends on the cause of the dog’s murmur. For example, if your dog has a grade 1 or grade 2 heart murmur, they usually don’t need any treatment. 

First, the vet will identify the underlying causes, and according to that, they give the proper treatment. This can be simple as a few dietary changes to medication and surgery for severe heart murmurs.

If your dog is suffering from a loud murmur or seems unwell, they may suggest tests and investigations such as:

  • X-rays
  • An ultrasound scan
  • An ECG (a heart trace)
  • Blood tests

The Bottom Line

Heart murmurs in dogs are a sign of underlying diseases. Sometimes with the simple treatment and medication, it can be treated, but sometimes they need surgery if it is caused by serious heart problems.

That’s why some dogs show symptoms of a heart murmur like difficulty in breathing, weakness, and cough, while some dogs don’t show any signs. That’s why it’s vital to get regular check-ups at the vet. The doctors can easily catch heart murmurs through your routine visits. 

So, if you think that your dog may be suffering from a heart murmur or you have any health concerns about your dog’s heart, please visit your vet without hesitation! They clarify all your doubts and questions about heart murmur in dogs and provide your dog with the right treatment.

I hope this in-depth guide on heart murmur in dogs has provided you with all the information you need. So, if you find this blog informative and helpful, please share it with your friends and family. 

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