Everything On The 6 Grades of Heart Murmurs in Dogs And Their Natural Treatments

Authored byVeronic Fournier - Sep 13, 2021


Dog, man's best friend, our best confidant! While we would like to keep them with us much longer than they are able, a certain percentage of dogs will be diagnosed with a heart murmur during their lifetime.


“My dog ​​has a heart murmur. What does that mean?"


A heart murmur is an additional abnormal sound heard when auscultating an animal's heart with a stethoscope. It sounds like wind between heartbeats. Is it serious?


It all depends on what’s causing the murmur and its grade. We will see this in detail below.


Follow the lead of thousands of satisfied pet parents and take the advice of our natural animal health experts. This article has been written especially for you, animal lover, to help you understand what is going on in the bodies of your furry companions, in order to give you all the tools you need to help them the best that you can.


Read on to learn more about canine heart murmurs and to get a list of the best natural treatments for your dog or puppy's heart condition.



What is a heart murmur in dogs


As mentioned above, a heart murmur is a sound heard between two heartbeats, which is actually a vibration caused by turbulence in the blood flow to the heart.


We talk about a systolic murmur when the sound is heard in conjunction with the contraction of the heart, and a diastolic murmur when the sound is heard between beats as the heart muscle relaxes. A continuous murmur is heard during most or throughout the cardiac cycle.



Heart murmurs in puppies, small breed dogs and older dogs


Heart murmur in puppies


In puppies with heart murmurs, you may have a murmur that is said to be innocent, or benign, meaning that it will go away over time, usually at around 12 to 15 weeks of age.


Some murmurs can also be associated with excitement, when the heart beats very quickly and the blood is pumping fast. Like the strings of a guitar, the structures of the heart vibrate with the passage of blood.


These are not to be confused with congenital murmurs, which are present from birth and are caused by a heart defect (a hole in a structure of the heart, for example).


Heart murmur in small dogs


We sometimes hear that heart murmurs are more common in dogs of small breeds. Indeed, certain breeds of small dogs, such as the King Charles Cavalier, are genetically predisposed to develop a pathological change in their mitral valve, resulting in a heart murmur.


Heart murmur in older dogs


In older dogs with heart murmurs, degenerative mitral valve disease is also the most common cause of a new heart murmur at this age. The mitral valve thickens, making it difficult to close during a heartbeat, resulting in a leak. This valve is one of the four valves directing blood flow in the right direction through the heart, so as you might expect, its malfunction can have serious consequences.



What causes a heart murmur in dogs?


As with the flow of a river brought about by rain, melting snow, or geology, the turbulent flow of blood resulting in a heart murmur can be caused by different things.


Typically, a heart murmur is caused by either a hole in a structure of the heart, a narrowing of a chamber or vessels in the heart (stenosis), a vibration of the structures of the heart, or when blood is pumped more strongly and faster than normal.


A heart murmur can be secondary to systemic disease, or be directly caused by acquired cardiopathy, which is a heart disease that develops during the animal's life.


We have already discussed degenerative mitral valve disease, which is a possible cause of a heart murmur, as well as innocent and congenital murmurs. Now let's look at some other possible causes of a heart murmur:

  • Anemia
  • Hyperthyroidism
  • Heartworms
  • Hypertrophic cardiomyopathy
  • Dilated cardiomyopathy


That being said, it is possible for an animal to suffer from any of these conditions without exhibiting a heart murmur on auscultation!



Symptoms of a heart murmur in dogs


As you would expect, the heart murmur symptoms in dogs go hand in hand with the cause! An animal with hyperthyroidism will not have the same symptoms as an animal with primary heart disease. These are the classic signs of heart disease:

  • Difficulty breathing
  • Coughing
  • Exercise intolerance
  • Excessive panting
  • Weakness and lethargy
  •  Heart murmur! (indeed, a murmur is a symptom in itself, a sign of a possible underlying condition and not a condition on its own)



Grades of heart murmur


If your pet has been diagnosed with a heart murmur, your vet has probably also given you the grade as well, usually ranging from 1 to 6. Grade is actually a way of qualifying that murmur by its intensity, with 6 being the loudest.


The grade is not necessarily characteristic of the stage of heart disease. In fact, this figure given by your vet does not directly correlate with the severity of the symptoms, it all depends on the cause of the murmur.


For example, in a vet clinic, I once encountered a dog with a grade 2 or 3 murmur that presented with coughing symptoms, while another with a grade 5 murmur was living a normal life. Let’s look at the characteristics of each grade of heart murmur below.


The grade is not the only characteristic used by vets to describe the heart murmur. They also use its tone, the location of its maximum point of intensity, its type (systolic, diastolic or continuous), its irradiation area, etc.


That being said, the assessment of a murmur is subjective. Although several criteria exist to describe a murmur, two vets could give a slightly different grade for the same murmur.


Dog heart murmur: Grade 1


A grade 1 murmur is heard after a long auscultation under perfect conditions, that is, in a quiet room with a cooperative patient and a good stethoscope.


It is a very soft murmur, localized and hardly noticeable.


Dog heart murmur: Grade 2


Easily audible when the stethoscope is placed directly where the heart is heard best.


It is a gentle murmur, but noticeable after a few seconds of auscultation. It is located in a single auscultation zone.


Dog heart murmur: Grade 3


The murmur is easily audible and as loud as the heartbeat. It is a murmur of moderate intensity, immediately noticeable and localized.


Dog heart murmur: Grade 3 Life Expectancy


All depending on the cause of the murmur, of course, the prognosis varies. If your dog is less than 3-4 years old, it is likely that this murmur is secondary to a congenital disease. If you have an older, small breed dog, chances are they have acquired heart disease.


So how long can a dog live with a heart murmur?


You will probably guess that it’s impossible to give a life expectancy related to a heart murmur grade until you know the cause, which is why I recommend that you follow your vet's advice on the next steps to take. They are in the best position to give you a prognosis, having in hand the results of the diagnostic tests specific to your dog.


Dog heart murmur: Grade 4


It's a loud murmur, louder than normal heart sounds. The murmur radiates to other areas of the chest. In other words, it is audible elsewhere other than at its point of maximum intensity.


Dog heart murmur: Grade 5


It is also a murmur with radiation. From a grade 5 heart murmur, a precordial thrill is palpable. In other words, the murmur can be felt manually on palpation.


In the vet clinic, I once saw a cat who had a grade 5 heart murmur and had no symptoms! Surprising given the intensity of its murmur!


Dog heart murmur: Grade 6


A grade 6 heart murmur is a very loud murmur, audible even when lifting the stethoscope slightly from the body. It is also characterized by a palpable precordial thrill. It is quite rare to see an asymptomatic animal with such an advanced grade of murmur, but anything is possible!


Treatments for heart murmur in dogs


As you might suspect, the first step to take is to find the cause of the murmur through various diagnostic tests, such as a heart ultrasound and an electrocardiogram. Then, depending on the findings, specific heart murmur treatments can be considered.


If, for example, blood tests show that the animal has hyperthyroidism, which is responsible for the heart murmur, it is likely that medication given to treat this primary cause will also resolve the issue of the heart murmur.


In other more serious cases when the animal has primary heart disease, surgery may be possible; it’s something to discuss with your vet. Some medications can also help control symptoms. Read on for natural solutions to help your dog with its heart murmur.


Dog Heart Murmur Natural Treatments


If you are looking for home remedies to support your dog's heart and treat its cardiac problems, I will equip you with a list of the best natural remedies and supplements that you can use as a home treatment to support the overall cardiac health of your dog.


Coenzyme Q10


The Coenzyme Q10 (CoQ10) is a powerful antioxidant which fights free radical damage that can leads to heart failure. It is found in your dog’s organism, especially in the heart, kidneys and liver. The CoQ10 has been shown to improve symptoms of congestive heart failure and reduce blood pressure and help the blood circulate faster.


Omega 3


The omega-3 fatty acids can be found in fish, fish and seafood oil (such as squid oil, krill oil), seeds (such as flaxseed, chia seeds) and plant oil (such as flaxseed oil, soybean oil and canola oil). Eating fatty acids reduces the risk of heart problems in dogs.




The leaves, flowers and berries of the hawthorn can be used to protect against heart disease and help control high blood pressure and high cholesterol. This plant increases the blood flow, the circulation and lowers the blood pressure of the dog.




Yes, this plant that grows in your yard can detoxify certain organs such as your dog’s heart and has diuretic effects to get rid of the body of excess fluid that can help your dog’s heart muscles to pump stronger.




Antioxidants work to deactivate free radicals and prevent damage of the free radical from occurring. It lowers the risk of coronary heart disease in dogs. Antioxidants can be found in plants, fruits, vegetables, some nuts and some meats, poultry and fish.


Online Homeopathic Consultation


Our Online Homeopathic Consultation is just what you need if you want to take care of your dog's seizures naturally.


Zumalka provides a personalized solution to target the root of your pet's problem, instead of just the symptoms. And all of this done in the comfort of your own home!


Instead of struggling through in-person appointments and waiting rooms, our consultations are 100% online via email and video call.


It's a real conversation with a real Homeopath about your pet — without all the hassle and miscommunication.





To conclude, learning that your pet is sick is extremely stressful. We sympathize with you if you are in this situation with your companion.




About the author

Veronic Fournier
Veronic Fournier


Véronique Fournier shares her extensive pet health know-how on Zumalka through her articles.

Véronique’s background as an animal wellness advocate began in Cégep La Pocatière in Quebec, which led to comprehensive internships and training with respect to the breeding, rehabilitation, and monitoring of various types of animals. The institutions she has worked with include the Quebec Aquarium and the SOS Miss Dolittle shelter, just to name a few.

Her immersion with various veterinary clinics in British Columbia and other places has made Veronique not just knowledgeable, but also quite perceptive in zeroing in on the right strategy to help keep pets in the best of health.

And can we get you in on a secret? Veronique shares that she has already made a lot of canine pals due to her stint as a foster mom in several shelters. Isn’t that cool?


  • Zumalka February 9, 2024 at 4:12 pm

    Hello Edie, we have reached out to you via email about your dog’s heart murmur. Keep an eye open for our email in your inbox. To answer your question, there is no contraindication for use of Vetmedin with our natural products.

  • Edie Gegolick February 9, 2024 at 4:08 pm

    Max is our senior rescue. Anywhere between 10-14 years old. Adopted Mar, 2020. Had 3/4 heart murmur. July, 2023 upgraded to HM 5/6. No natural products were recommended. Some CHF. On Vetmedin since Oct, 2023 but would rather be all natural.. Gently cooked raw diet. Added veggies, supplements, minerals. Rare coughing and no symptoms. Can this be used while on Vetmedin? And is there any chance of a heart murmur going from 5/6 to 3/4?

  • Zumalka September 20, 2023 at 3:07 pm

    Hi JP, thanks for your great question. I’ve submitted it to the homeopath, you will get an answer shortly via email. Thanks for your patience !

  • JP September 20, 2023 at 3:06 pm

    My vet told me my puppy, 3.5 months old, has a grade 3 heart murmur. I’m assuming it’s congenital. Didn’t say whether it was systolic, dystolic, or continuous. Does it really matter if it’s congenital? How is any homeopathic remedy supposed to help with this?

  • ZUMALKA May 29, 2023 at 10:10 am

    Dear Madelyn,
    Stage 6 heart murmur is the most severe stage and can be felt and have more noticeable symptoms. At this point it is important to help keep your dog comfortable and avoid strains on the heart. We have sent you a private email so we can get more details for you and give you more targeted advice on your dog’s situation.

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