By Courtney Prue | January 5, 2024

Murmurs and Heart Disease in Dogs

Causes, Symptoms, Treatments, Home Care and Life Expectancy

Heart disease is a common condition in dogs, especially as they age. The diagnosis is often picked up on a routine physical exam with the detection of a heart murmur. It can be scary to hear that your beloved pet has an issue with something as vital as their heart, but it is important to understand that with the right treatment and care, many dogs can continue to lead happy and comfortable lives. This guide will cover everything you need to know about heart disease in dogs, including causes, symptoms, diagnosis, treatment, and at-home care tips. We will also touch on quality of life and the value of palliative care, to keep your pet as comfortable for as long as possible.

What is a heart murmur? The vet said my dog has a heart murmur; what does that mean?

A heart murmur is an abnormal sound heard when listening to a dogs heart with a stethoscope. Normally, a dogs heart produces two distinct sounds, described as “lub” and “dub.” A heart murmur is an extra sound that can be heard between the two sounds, creating a “shooshing” or “whooshing” sound. This sound indicates turbulent blood flow through the heart. This turbulence can be created by any change to the normal smooth movement of blood through the heart. This includes narrowing, expansion, obstructions, other structural changes and changes to the consistency of the blood.

A heart murmur’s grade, ranging from 1 to 6, describes the loudness of the murmur. A grade 1 heart murmur is soft, while a grade 6 heart murmur is loud and can be felt with a hand on the chest. In dogs, higher grades usually indicate more significant heart disease.

What is heart disease in dogs?

Heart disease refers to any condition that affects the heart’s ability to function properly. There are several different types of heart disease that can affect dogs, including:


      • Congenital heart disease: This is a heart defect that a dog is born with.
      • Valvular heart disease: This is a condition in which the valves in the heart do not function properly, leading to blood flow problems.
      • Cardiomyopathy: This is a disease of the heart muscle itself, which can cause it to become weak or enlarged.
      • Heartworm disease: This is a condition caused by a parasitic worm that lives in the heart and pulmonary arteries.

What types of heart disease can dogs get? What heart disease is common in dogs?

There are several types of heart disease that can affect dogs, each with its own set of causes, symptoms, and treatment options.

Some of the most common types of heart disease in dogs include:


      • Mitral Valve Disease (MMVD): This is a type of heart disease that affects the mitral valve, which is responsible for controlling blood flow between the left atrium and ventricle. In MMVD, the valve thickens and doesn’t close properly, allowing blood to flow backwards in the wrong direction. This type of heart disease accounts for approximately 75% of all canine heart disease cases. Small breed dogs are particularly at risk, such as Cavalier King Charles Spaniels.  According to a study by the American College of Veterinary Internal Medicine, over 50% of Cavaliers over the age of 5 have developed some degree of MMVD.
      • Dilated Cardiomyopathy (DCM): This is a type of heart disease that affects the heart muscle, causing it to become thin and weakened. As a result, the heart cannot pump blood effectively, leading to heart failure. This type of heart disease is most commonly seen in large and giant breeds, such as Great Danes, Boxers, and Doberman Pinschers.
      • Pulmonary Stenosis: This is a type of heart disease that affects the pulmonary valve, which controls blood flow between the right ventricle and the pulmonary artery. In pulmonary stenosis, the valve becomes narrowed, making it harder for blood to flow through it. This type of heart disease is most commonly seen in certain breeds, such as Bulldogs, Terriers, and Samoyeds.
      • Aortic Stenosis: This is a type of heart disease that affects the aortic valve, which controls blood flow between the left ventricle and the aorta. In aortic stenosis, the valve becomes narrowed, making it harder for blood to flow through it. This type of heart disease is most commonly seen in certain breeds, such as Boxers, Bulldogs, and Rottweilers.

What are common causes of heart disease in dogs? How did my dog get heart disease?

There are several factors that can contribute to the development of heart disease in dogs, including:
      • Age: Older dogs are more likely to develop heart disease.
      • Breed: Certain breeds are more prone to heart disease than others, such as Cavalier King Charles Spaniels and Doberman Pinschers.
      • Genetics: Some forms of heart disease are hereditary.
      • Diet: Diets deficient in vital vitamins and amino acids can lead to Dilated Cardiomyopathy. Commercial diets are balanced to include everything needed to support a healthy heart. 
      • Infection: Some infections, such as heartworm disease, can lead to heart disease.

How do I know if my dog has heart disease? What are common signs of heart disease in dogs?

The symptoms of heart disease in dogs can vary depending on the type and severity of the condition. Some common symptoms include:

      • Coughing, especially at night or after exercise
      • Difficulty breathing
      • Rapid breathing or panting
      • Fatigue or weakness
      • Fainting or collapsing
      • Loss of appetite or weight loss
      • Swelling in the abdomen or limbs

If you notice any of these signs, book a consultation with your veterinarian to discuss possible causes and perform any indicated diagnostics.

How is heart disease diagnosed in dogs? What will the vet do to test my dog with a heart murmur?

Once a heart murmur has been detected by your veterinarian, further diagnostics can help identify the cause, indicate the severity, track disease progress and treatment efficacy and more.


      • X-rays: These can show the size and shape of the heart and can detect fluid buildup in the lungs.
      • Electrocardiogram (ECG): This measures the electrical activity of the heart and can detect abnormal rhythms.
      • Echocardiogram (Echo): This is an ultrasound of the heart that can show how well the heart is functioning and detect any abnormalities.
      • Blood tests: These can help detect any underlying health conditions that may be contributing to the heart disease.

Can heart disease be treated in dogs? What is the treatment of heart disease in dogs?

The treatment of heart disease in dogs will depend on the type and severity of the condition. Some common treatments include:


      • Medications: There are several medications that can help manage heart disease in dogs, including:
        • Pimobendan which increases heart muscle strength and improved blood flow
        • Diuretics to reduce fluid buildup
        • ACE inhibitors to help dilate blood vessels
        • Beta-blockers to slow the heart rate.
      • Dietary changes: A diet that is low in sodium and high in protein can help manage heart disease in dogs.
      • Exercise restriction: In some cases, it may be necessary to restrict your dog’s exercise to prevent overexertion.
      • Surgery: In some cases, surgery may be necessary to repair or replace damaged heart valves or to remove heart tumours. These are specialist surgeries and will involve referral. 

The medical management of heart disease can be confusing and overwhelming. Speak to your regular veterinarian or get in touch with our team today for a personalised discussion. 

Can a heart murmur in a dog cause sudden death? What should I do in an emergency?

In some cases, heart disease in dogs can lead to an emergency situation, especially when their lungs are impacted. If you suspect your dog is in distress, it’s crucial to act quickly and seek veterinary care immediately.  
      • Ongoing difficulty breathing or shortness of breath
      • Rapid breathing or panting that doesn’t settle even when at rest 
      • Blue or grey gums and tongue
      • Collapse or loss of consciousness
If you observe any of these symptoms, seeking immediate veterinary attention is important. Time is critical in emergency situations, and a delay in treatment can have serious consequences for your dog’s health. Don’t hesitate to call your veterinarian, our team or an emergency veterinary clinic for guidance on how to proceed.  

What are possible complications for my dog with a heart murmur or heart disease? What will happen if my dogs heart murmur is not investigated or treated?

Unfortunately, there can be several complications associated with heart murmurs and heart disease in dogs. Some of these can be serious, while others can be managed with appropriate treatment. Here are some of the most common complications to be aware of:  
      • Congestive heart failure: This occurs when the heart is no longer able to effectively pump blood to the body, causing fluid buildup in the lungs or other areas of the body. Congestive heart failure can be life-threatening if not managed properly.
      • Pulmonary edema: This is a condition in which fluid accumulates in the lungs, making it difficult for the dog to breathe. It can be caused by several factors, including congestive heart failure.
      • High blood pressure (hypertension): The body can compensate for an inefficient heart by increasing the blood pressure, which can cause secondary damage to other organs
      • Arrhythmias: This refers to abnormal heart rhythms that can be caused by heart disease. Some arrhythmias can be benign, while others can be serious and require treatment.
      • Blood clots: Dogs with heart disease are at an increased risk of developing blood clots, which can lead to serious complications like stroke or heart attack.
      • Sudden death: In severe cases of heart disease, sudden death can occur without warning. This is more likely in dogs with advanced heart disease or those that are not receiving appropriate treatment.
The medical management and monitoring of heart disease can be confusing and overwhelming. Have an honest conversation with your veterinarian or get in touch with our team today for a personalised discussion.

How do I manage my dog’s heart disease at home?

Here are some tips to help you optimise your dog’s care at home:

      • Monitor your dog’s breathing: This includes the effort used, as well as the rate. An important factor to monitor is their resting respiratory rate. While deeply asleep, count the number of breaths taken in 1 minute (or in 15 seconds and then multiply by 4). The rate should be between 10-20. If it is over 30 breaths per minute, ring the vet ASAP as this indicates possible congestive heart failure.
      • Create a comfortable living space: Ensure your dog’s living space is warm, quiet, and comfortable. 
      • Reduce excitement and manage stress: Stress and high-energy activities can put extra stress on the heart and lungs. Provide low-energy exercise and play, keep their routine consistent, minimise loud noises, and provide a calm environment.
      • Regular check-ups: Your vet will monitor your pets condition and make changes to their treatment plan as necessary.
      • Consider palliative care to maximise comfort for as long as possible.

An in-home veterinary assessment can also be helpful to identify any other areas of improvement, that can help your beloved pet stay comfortable for as long as possible.

How long can my dog live with heart disease? Can my dog live a long life with heart disease?

The prognosis for dogs with heart disease varies depending on the type of heart disease, the severity of the disease, and how well it responds to treatment. 

While some dogs with heart disease can live for several years with appropriate treatment and management, others may have a shorter life expectancy. Your veterinarian can provide you with a more accurate prognosis based on your dog’s individual case. 

For MMVD, the most common type of heart disease in dogs, approximately one-third (30%) of dogs diagnosed will experience significant disease. Early diagnosis and treatment are vital to slowing down the progression of the disease.

Unfortunately, once a dog with MMVD has signs of congestive heart failure, the disease is almost always terminal, with end-of-life decisions often made within 6 to 18 months. At this stage, their quality of life is significantly impacted, and palliative care or euthanasia may be the kindest options.

End-of-Life Care Tips:

If your dog’s heart disease has progressed to a point where treatment is no longer effective or its symptoms are too severe, it’s important to consider end-of-life care options, including possibly putting your dog to sleep (euthanasia). This can be an overwhelming and distressing thing to even think about. Your regular veterinary clinic and our team at Rest Your Paws are here to support you and provide compassionate care for your beloved pet throughout their journey.

Here are some end-of-life care tips for dogs with heart disease:

      • Keep them hydrated and well-nourished with some delicious food
      • Spend quality time with them, making the most of every moment, such as with a bucket list
      • Offer a calm and peaceful environment, free from stressors that can exacerbate symptoms
      • Administer medications as prescribed for pain management and symptom relief. Your veterinarian may increase doses of medications such as diuretics to reduce fluid accumulation.
      • Closely monitor their breathing rate and effort as described above.
      • Evaluate their Quality of Life regularly or contact a palliative care vet to help you
      • Consult our End of Life Care Pack to get prepared to put your dog to sleep
      • Track good days and bad days on our Quality of Life Assessment Calendar

We understand that facing a diagnosis of heart disease in your beloved dog can be a difficult and emotional time. However, with early detection, proper treatment, and careful management, your dog can continue to enjoy a happy and fulfilling life. Remember to work closely with your veterinarian to develop a comprehensive care plan that meets your dog’s needs. As your dog’s caretaker, staying positive and providing plenty of love and support throughout the journey is important. Cherish the time you have with your furry companion, and make every moment count. 

Reach out to your regular veterinary clinic or our team for the guidance and care you and your furry friend deserve. If you want to learn more about putting your pet to sleep, dog euthanasia at home, options to put your pet down at home, costs of euthanasia at home or what it looks like to put your pet to sleep at home, speak to your vet, call us on 0422 157 675 or visit our website.


We offer in-home palliative care and euthanasia for cats and dogs 7 days a week across Australia. Support your beloved pets in comfort and say goodbye with peace and dignity with professional and experienced end-of-life support.

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