Heart failure in dogs

Written by Dr Andrew Miller MRCVSDr Andrew Miller MRCVS is an expert veterinary working in the field for over 10 years after graduating from Bristol University. Andy fact checks and writes for Pure Pet Food while also working as a full time veterinarian. Pure Pet FoodPure Pet Food are the experts in healthy dog food and healthy dogs featured in media outlets such as BBC, Good Housekeeping and The Telegraph. Working with high profile veterinary professionals and nutritionists, Pure Pet Food are changing dog food for the better. - Our editorial process

Heart failure in dogs is sadly a common occurrence, particularly in old dogs. It’s sometimes also referred to as cardiac failure, or congestive heart failure. Although hearing the words “heart failure” can seem terrifying, many dogs can actually live long and happy lives with the condition provided they are given regular medication.

Read on to find out everything you need to know about heart failure in dogs, including what it is, how to spot it, and how it’s treated.


Heart failure in dogs is simply a shorthand way of saying that your pooch’s heart is failing to pump blood throughout the body as well as it should. This leads to the dog’s circulatory system becoming congested. Many cases are slow-onset, meaning they appear slowly over time and gradually worsen. Heart failure is not a disease in itself, but it is often caused by heart disease.

When a dog’s heart is failing, some blood will be leaking back through the different chambers of the heart into the lungs or into the body and backing everything up, a bit like a traffic jam. Because the blood isn’t moving correctly, the heart has to work much harder to try and pump it around the body, which means a pup’s heart rate and blood pressure will become much higher than normal. It will also cause fluid to leak into other areas of the body or into the lungs.

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A failing heart will become much larger than normal too, putting physical pressure on the lungs and windpipe as they become squashed inside your dog’s chest. This is why most pups suffering from heart failure cough a lot, particularly at night or when they are picked up.

Because the heart isn’t able to pump enough blood around the body, there won’t be enough oxygen carried around to the other organs and tissues. In some cases, a dog’s other internal organs can suffer from damage due to a lack of oxygen.


Congestive heart failure is simply another name for heart failure in dogs. It still means that the heart is not working as well as it should and the condition will progressively worsen without treatment.


There is no magic number we can offer up as the life expectancy of a dog with congestive heart failure. Depending on how severe your dog’s condition is and how well they respond to treatment, they may only be given a few weeks or months to live, or they might be able to live out a long and comfortable life.

Normally, dogs can live a long and happy life provided they receive daily medication. Meanwhile, animals with advanced stages of heart failure can survive for 6-14 months after diagnosis.

However, heart failure in dogs that’s left untreated will get progressively worse and become fatal.


There are several types of heart failure in dogs, which are categorised according to the area of the heart that’s affected.

The first type is known as left-sided heart failure. This is when the mitral valve fails. It’s so named because the mitral valve is on the left-hand side of your pooch’s heart, separating the atrium and the ventricle. When this valve fails, blood can leak back through it and into your dog’s lungs, causing pulmonary oedema. If left untreated, this left-sided heart failure can progress until the whole heart is affected.

The other type is right-sided heart failure. Right-sided heart failure is caused by a failure of the tricuspid valve, which is on the right side of your dog’s heart separating the ventricle and the atrium. When the valve fails, blood leaks back through it into the atrium where it can then enter the systemic circulation which is the main circulatory system of your dog’s body. As blood enters back into the body and congests circulation, it causes fluid to build up in other areas of the body. This often leads fluid to build up in the abdomen, a condition known as ascites, which causes a swollen belly. Another commonly affected area is your dog’s limbs, where fluid can leak from their veins causing their legs to swell in a condition called peripheral oedema.

A third type of heart failure is biventricular failure, which occurs when both the valves in the left and right-hand side of the heart are not working properly.



Congestive heart failure is often a result of heart disease. Heart disease is not a specific illness, but an umbrella term for a number of different problems within the heart. These lead to or cause the heart to be unable to work correctly or perform as well as it should.

There are many different types of heart disease, including chronic valvular disease, mitral valve disease, dilated cardiomyopathy, or congenital heart disease to name a few. It’s estimated that around 10% of dogs will suffer from some form of heart disease.

Dogs can also develop valvular disease, which means the valves of their heart have weakened and no longer seal properly, so blood leaks back through the valve into other areas of the heart or body. It’s estimated that mitral valve disease specifically accounts for 80% of all cases of heart failure in dogs.

Congenital heart disease is something your dog would have been born with, and there are a few different types your pup could have. Fortunately, congenital heart disease is rare and thought to account for fewer than 5% of cases of heart disease in dogs.

Although it’s not a form of heart disease, an arrhythmia, or abnormal heart rhythm, can also lead to heart failure because it can impact the performance of your pooch’s heart.

As well as heart disease, heart failure in dogs can be caused by a number of other factors that are either external or related to other areas of your dog’s health.


One of the most horrifying causes of heart failure is a parasite called heartworm. These worms make their home inside your dog’s heart and can block up the valves inside the organ, or fill up an entire chamber of the heart.

Obesity puts increased pressure on a dog’s heart because it needs to pump harder to be able to move blood throughout the larger body. Being overweight or obese will increase your dog’s risk of developing heart disease, which in turn leads to heart failure.

Your dog’s diet can contribute to your dog’s risk of developing heart disease, and as a consequence, heart failure. Firstly, a lack of the amino acid taurine in your dog’s diet can lead to the development of dilated cardiomyopathy, a form of heart disease.

A bacterial infection in your dog’s body could also migrate and infect their heart, causing inflammation. Most of these bacteria enter through the mouth or grow in your dog’s mouth if they have poor oral health. There is a link between the development of gum disease and an increased risk of heart failure in dogs (and humans too).

Other infections could also cause havoc on your pup’s precious heart. One of the most notorious is parvovirus, which can infect the heart muscle and cause heart failure.

Other health conditions can raise your dog’s risk of heart failure. For example, hypothyroidism often lowers a dog’s heart rate below the normal rhythm, and abnormal heart rhythms can contribute to heart failure.

Finally, as with many illnesses, genetics can play a part in whether or not your dog develops heart disease. Just like with humans, you need to ask if there is heart disease and heart failure in your pup’s family history.


Any dog of any size, breed, or gender can develop heart failure, but it becomes more common in old dogs. Other factors such as obesity, gum disease, and a heartworm infestation can all increase a dog’s risk of heart failure and cause them to develop heart problems much earlier in life.

All breeds could develop heart failure, but the most likely cause will vary depending on a dog’s size.

Big breeds of dog are more likely to develop the heart disease dilated cardiomyopathy, which can progress into heart failure. Some breeds at risk include the Dobermann, Great Dane, Labrador, Golden Retriever, and the Irish Wolfhound. Smaller dogs can still develop DCM, and Cocker Spaniels seem more prone to this disease than other small to medium breeds.

Meanwhile, small breeds of dog are at greater risk of developing mitral valve disease. Some specific breeds prone to the problem include Chihuahuas, Miniature Schnauzers, Toy Poodles, Shih Tzus, Maltese, and the Cavalier King Charles Spaniel.

There are also a few breeds of dog that are particularly prone to certain heart diseases and heart failure, including all of the breeds mentioned above.

Perhaps the breed more likely than most to develop heart failure is the Cavalier King Charles Spaniel. This is because they are especially prone to mitral valve disease, and more than half of all Cavaliers will develop the disease by the time they are 5 years old. A few years ago 100% of Cavs older than 10 had the condition, but a breeding scheme has led to a decrease. Sadly, heart failure is the most common cause of death for this beloved breed.

Meanwhile, Boxers are predisposed to a condition called arrhythmogenic right ventricular cardiomyopathy (ARVC), to the point it is often simply called “Boxer cardiomyopathy”. Boxers are also at risk of the heart muscle itself deteriorating, and this predisposition to heart disease leads to the breed being prone to heart failure.


While there are different stages of heart disease in dogs, some of these stages relate to heart failure. Stage C of heart disease is when a dog begins to show signs of congestive heart failure, whilst stage D is when a dog has congestive heart failure and doesn’t respond to treatment.

Speaking of heart failure itself, there are two main types of heart failure in dogs. The first is the compensated phase, which means the dog’s body is able to compensate for the heart’s decreasing efficiency. At this stage, a dog will not show any symptoms, or they will have mild signs of illness that are easy to manage. The second type is the decompensated phase which is when the heart failure becomes more severe and a dog starts showing symptoms.


The signs and symptoms of heart failure in dogs will often be similar regardless of what side of the heart is failing. The general signs of heart failure in dogs include:

  • Difficulty breathing

  • Coughing (especially at night or when picked up)

  • Excessive panting

  • Exercise intolerance

  • Fatigue

  • Lethargy

  • Weight loss

  • Loss of appetite

  • Fainting

  • Collapse

  • Heart murmur

  • Blue/grey colour gums and tongue (due to lack of oxygen.)

  • Swollen belly

When the right side of the heart fails, excess fluid can build up in areas of your dog’s body. This is associated with symptoms including:

  • Swollen belly (ascites)

  • Swollen limbs (peripheral oedema)


Early diagnosis and treatment of heart failure usually improve your dog’s prognosis, so if your dog is showing any symptoms that could be heart failure, you should take them straight to the vet as soon as you can.

Your vet will physically examine your dog, which will include listening to their heart using a stethoscope to see if they can hear anything unusual that could be a sign of heart failure. The first audible sign is a murmur, and this is caused by unusual blood flow. The second sound is a crackling in your dog’s lungs, caused by blood or fluid gathering inside them.

They will also check your pup’s heart rate and blood pressure because these both rise higher than average because of the increased pressure on the heart to pump harder and faster to push blood around the body. They might also check your pooch’s blood oxygen saturation, as a lower level of oxygen in their blood could indicate that the heart is failing to pump blood around the body correctly.

If your dog shows these symptoms, your vet will do an x-ray of their chest to examine their heart, which will be larger than normal and very round if it’s failing. They will also conduct an echocardiogram, which is an ultrasound of the heart that allows them to see the organ and how it moves in real-time, so your vet can see any abnormal movements in your pup’s heart.

Finally, the vet will also conduct an electrocardiogram (ECG) which is used to check the electrical current of your dog’s heart. Again, any abnormality here is a sign that the heart is failing.

As well as all of these tests to try and see if your dog is suffering from heart failure, your vet might conduct other forms of testing, such as blood or urine tests, to rule out any other possibilities that could be causing your dog’s illness.


Sadly, there is no guaranteed way to prevent heart failure in dogs, although keeping them in good overall health should help to improve the health of their heart.

Keeping your dog active will help to improve their overall health and to exercise their heart muscle to keep them strong.

Feeding them a healthy diet should improve your pup’s overall health, and there are a number of nutrients such as omega-3, vitamin E, taurine, coenzyme Q, and carnitine that are all effective in preventing and treating heart disease. These can be found in many foods or supplements. We’ll talk about this in more detail below in the “best dog food for heart failure” section.

Keeping active and eating well will also prevent obesity, which is one of the biggest risk factors for heart disease and heart failure in dogs. So keeping your dog slim should help lower their chances of developing heart failure.

Maintaining good oral health by brushing your dog’s teeth regularly will also help to prevent problems with your pup’s ticker. This is because gum disease and poor oral health are linked with an increased risk of heart disease which could lead to heart failure. Therefore keeping your pup’s gnashers clean should remove another risk factor.

There are certain causes of heart failure that can be prevented though, such as those caused by heartworms or parvovirus. Keeping up a regular antiparasitic medication will stop heartworms from infesting your poor pooch, and therefore prevent heart failure caused by the nasty parasite. Meanwhile, vaccinating your dog against parvovirus will protect your pup from the disease, which can infect the heart and cause it to fail.


Treatment for heart failure in dogs will vary based on the cause of the condition. The aim of any treatment is to improve your dog’s quality of life and to extend their lifespan by improving their heart’s function and controlling the effects of heart failure. This will include lowering a dog’s blood pressure, removing excess fluid from the body, and controlling any abnormal rhythms.

Modern medical practice has improved the outlook of dogs with heart failure significantly but there is no magic cure. Medication and lifestyle management simply slow down the progression of heart disease and extend the dog’s lifespan, whilst offering them a much better quality of life.

When your dog is first diagnosed with heart failure, they might require prompt and aggressive treatment. For example, if they are suffering from acute respiratory distress, they must be given oxygen and placed in an intensive care unit. This is often done by placing the pooch in an oxygen cage. They might also conduct a chest drain, which will require the use of a needle in your dog’s chest to remove some of the excess fluid.

As well as immediate treatment to prevent any acute and serious problems, a dog will be given various drugs to control the effects of heart failure. Many of these medicines will need to be continued for the rest of the dog’s life.


Dogs suffering from mitral valve insufficiency or dilated cardiomyopathy will probably be given Pimobendan. This medication is effective in improving the force that the heart can pump with, strengthening the muscle’s contractions and improving blood flow.

Your dog will also be given an ACE inhibitor such as benazepril, captopril, or enalapril. These will relax your pooch’s blood vessels, which will then reduce their blood pressure and blood volume. Ultimately this makes pumping blood around their body easier so there is less strain on the heart.

Diuretics, such as furosemide, will be prescribed to help get rid of excess fluid in their body. These drugs stimulate kidney function so that they remove more liquid from the body. A dog with heart failure will need to take diuretics for the rest of their life.

Some dogs might also be given beta-blockers to slow their heart rate.


Sometimes, surgery might be required to correct an injury or fault inside the heart mechanism. For instance, if your dog has a torn valve, then surgery can be carried out to fix it. Some dogs might have a pacemaker fitted to regulate their heartbeat.

However, most cases of heart failure in dogs do not require surgery to treat, and surgical options would be limited and complex. The majority of dogs with heart failure are prescribed the medications listed above and advised on lifestyle changes to help manage their condition. Both a healthy lifestyle and daily medication will prevent further deterioration of your pooch’s heart and it will improve their quality of life so that they can continue to live a long and happy life.


Dogs with heart failure need ongoing treatment for the rest of their life, which will include daily doses of some of the medications listed above. They will also require regular checkups and changes to their lifestyle to improve their wellbeing and reduce any risk of further complications.

Your vet will recommend dietary changes to help improve your dog’s condition and to prevent any further stress on their heart caused by excess sodium. Some supplements have also been shown to improve the health and quality of life for dog heart failure patients. Scroll down to “the best dog food for heart failure in dogs” section to find out more.

Another lifestyle change will be to stop your dog from taking part in any strenuous exercise, as this will put increased pressure on their heart. Your dog should continue with daily walkies and exercise to remain physically fit and to maintain their heart muscle, however, all exercise should be gentle and according to your dog’s ability. Your vet will discuss what your pooch can and can’t do with you based on their individual needs.

You will also need to reduce stress in your dog’s environment as much as possible, and removing anything that could be causing your dog anxiety. This is because stress raises the heart rate, which will add more pressure on your pup’s heart which is already working harder than normal just to pump blood around the body. Your vet might prescribe anti-anxiety medication for your dog if they suffer from respiratory fits or if there is an upcoming period of high stress, such as bonfire night and all the fireworks going off.

Once your dog’s condition has been stabilised, they will still need to attend routine check-ups with the vet throughout the rest of their life to monitor their condition. These check-ups allow your vet to find any signs of decline in your dog’s health which they can then treat early. It also means they can assess the effectiveness of the treatment your dog is receiving and make any adjustments to it as necessary to improve your pup’s health and wellbeing.


Nutrition is vital in the management of heart failure patients, and one of the first things your vet will advise you to do is to ensure that your dog eats a low sodium diet. This is because excess salt increases fluid retention and blood pressure, putting additional strain on your dog’s heart. You will need to make sure your dog’s food is balanced so it still provides all the nutrients and calories they need but without much salt. You’ll also need to make sure any treats or human foods your dog eats don’t contain salt.

Including plenty of healthy fatty acids like omega-3 in a dog’s diet has also been shown to improve their condition. This is because omega-3 reduces inflammation and the risk of sudden cardiac death, plus it might have the potential to help to control arrhythmias.

As well as omega-3, other dietary supplements such as vitamin B, taurine, carnitine and antioxidants including coenzyme-Q and vitamin E are advised for dogs with heart failure. These nutrients have all proven effective in preventing and treating various types of heart disease. These nutrients can all be given as supplements, but they can also be found in many foods.

For example, fish, organ meats, spinach, cauliflower, and broccoli are all rich in coenzyme Q, and fish will also contain a lot of omega-3. Meat, fish, and eggs are also sources of carnitine and taurine, and beef is an especially good source of both. Meanwhile, vitamin E can be found in a wide variety of foods from salmon and peanuts to red peppers and mango.

You should discuss all dietary changes and supplements with your vet, and they will be able to advise you on what dosage of supplements will be safe and effective for your individual pooch.


The most important home remedy for heart failure in dogs is to feed your dog a low-sodium, healthy diet, which is the same advice that your vet would recommend. Even the supplements that are advised as a home remedy for heart failure are the same as those advised by your vet, and what we have listed above (Coenzyme-Q, Omega-3, etc.).

The only other home remedy sometimes mentioned online is feeding your dog a dandelion leaf tincture or dandelion leaf tea. Dandelion leaf is a natural diuretic, and heart disease treatment usually involves giving your dog a diuretic medicine in the form of a tablet every day. Dandelion leaf is touted as a natural, easy-to-administer alternative. Although we know dandelion is a natural diuretic, there isn’t a great deal of study on its effect with heart failure patients, and fewer still with the effect on dogs.

Other herbal remedies such as hawthorn have some positive effect on human patients suffering from heart failure, but again, more research is needed including a study on the effect on our pets.

You can discuss with your vet if they think taking dandelion leaf tincture would benefit your dog. However, the diuretics prescribed by your vet are incredibly safe and effective and backed up by years of research and thousands of successful treatments of dog patients in the real world. And even if your dog is taking this herbal tincture, they will still need other daily medications to control the effects of their failing heart.


The prognosis for a dog with heart disease can vary dramatically depending on the area of the heart affected, the severity of the condition, and how well your dog responds to treatment.

In most cases, a dog diagnosed early that receives prompt and continued veterinary treatment to manage the condition will go on to live for many years. Treatment also vastly improves your dog’s quality of life, allowing them to continue gentle exercise, breathe easily, and relieve the pressure on their organs.

If untreated, your dog’s condition will progress, their health will decline, and their heart disease will eventually prove fatal.

Sadly, some dogs will be diagnosed with severe heart disease, or be diagnosed as the condition enters its final stages, and these poor pups might only have a few days, weeks, or months to live.

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