Heart disease 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 disease is quite common in dogs, affecting just over 1 in 10 dogs. Yet you might never have considered that your pooch could have a poorly ticker. Although heart disease sounds scary, and some cases can sadly be fatal, many dogs can live a long and happy life even with heart problems.

Like many conditions, spotting the signs of heart disease early and providing veterinary treatment will help to increase your dog’s life expectancy and improve their quality of life.

Here’s everything you need to know about heart disease in dogs including how to spot it, how it’s treated, and what the outlook is like for your furry friend.

What is heart disease in dogs?

Heart disease, which can also be called cardiovascular disease, is a general term given to a dog who suffers from an abnormality or a health condition that affects their heart or blood vessels.

It is not always a disease either. Heart disease could be a disease, a physical defect, a disorder in how the organ functions, or a problem with the electrical activity that keeps the heart beating.

The term “heart disease” covers a range of different conditions which may be congenital or acquired. A congenital defect means that your pup would have been born with the problem, whilst an acquired condition is something that has developed during your dog’s lifetime.

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So in short, heart disease in dogs can cover almost any problem which affects their heart.

Usually heart problems don’t go away on their own and if left unmonitored and untreated they will get worse and your dog’s heart and health will deteriorate, and it can become fatal. Heart disease can also progress into heart failure.

Heart disease and dog’s life expectancy

It’s incredibly difficult to predict the life expectancy of a dog with heart disease. How long they will live for will depend on the type of heart disease they have, the stage of their condition, how well they respond to treatment, and what their overall health is like.

Some dogs can live with mild, early stages of heart disease for a long time without you or the dog ever noticing there’s an issue. Other dogs with more moderate cases can still respond amazingly to treatment and live a long and happy life despite having heart disease.

Even dogs with advanced cases of heart disease can live happily and comfortably for a relatively long time provided they respond to treatment. Most dogs even with severe illness live for an average of 9-13 months after diagnosis. Many dogs keep going for much longer, with some dogs going on to live for over two years after starting treatment.

However, the reverse is also true and sadly some individual dogs with serious heart disease won’t respond to treatment and their life expectancy will shrink dramatically, sometimes to as little as a few days or weeks.

Types of heart disease in dogs

There are many different types of diseases that can affect a dog’s heart. Some conditions are relatively common, particularly amongst certain breeds, whilst others are quite rare.

The different types of heart disease can be classified in a number of different ways. The most important classification in the types of heart disease is between congenital conditions which a dog is born with, and acquired conditions that develop during their lifetime. Acquired heart disease is far more common, making up around 95% of cases of heart disease in dogs.

Acquired conditions can then be categorised depending on how they were caused, such as degenerative conditions which happen naturally with age, or infectious which is the result of damage to the heart caused by a bacterial, fungal, viral, or parasitic infection. Heart disease can also be divided into short-term or long-term conditions.

Types of heart disease in dogs can also be determined according to the clinical stage of disease and the area of the heart that has been affected (for example, left heart failure vs right heart failure). If there is a physical defect or a fault with the electrical activity that keeps the heart pumping, the type of heart disease will be classified according to what is being affected.

Some of the different types of heart disease in dogs includes:

●      Congenital heart defects (EG: ventricular septal defect)

●      Arrhythmias (EG: atrial fibrillation, sick sinus syndrome)

●      Degenerative valve disease

●      Chronic valvular disease (CVD)

●      Mitral valve disease (MVD, a common form of CVD)

●      Dilated cardiomyopathy (DCM)

●      Hypertrophic cardiomyopathy

●      Pericardial disease

●      Myocarditis

Stages of heart disease in dogs

There are 6 stages of heart disease in dogs which are used to grade how severe your dog’s heart disease is.

The four main stages are stage A, B, C, and D, but stage B is further divided into stage B1 and B2. Each classification represents a more severe stage of heart disease, with D being the most advanced stage of disease.

Stage A

Strangely, stage A doesn’t actually mean your dog has heart disease. Stage A means that your dog is at high risk of developing heart disease, but doesn’t have it yet.

Stage B

Stage B is still relatively mild, but cardiac changes have begun to appear. In stage B, your dog will have an audible heart murmur but no other signs of heart disease or failure. Stage B is further divided into stage B1 and B2.

In stage B1, your dog shows the same signs as in stage B but their heart appears normal when viewed under X-Ray. Meanwhile stage B2 is when your dog has the signs of stage B but their heart also appears larger than normal or out of the ordinary in an X-ray.

Stage C

Stage C is when things get more serious, and your dog has visible signs of heart disease or failure and requires treatment.

Stage D

Stage D is the most severe and means that your dog’s condition is advanced and difficult to manage, or that they are no longer responding to treatment.

What causes heart disease in dogs?

Congenital heart disease is caused by something your puppy is born with. It could be a defect caused by developmental problems when your puppy was growing in their mother’s womb, or an inherited problem. These only make up a small fraction of cases of heart disease in dogs.

Around 95% of heart disease in dogs is acquired and developed during your dog’s lifetime, and there are a number of different causes of acquired heart disease in dogs.

One of the most common causes of heart disease is simply aging. As your dog’s body gets older it gets weaker, and there is natural wear and tear on the organs including the heart. Most cases of heart disease are naturally caused by the aging process.

Various infections and trauma to the body can also damage your dog’s organs and if their heart suffers an injury or infection, it can develop into heart disease.

Because there are a number of different diseases and conditions that can affect your dog’s heart, there are a number of different causes which could trigger them. However, old age and infection are the largest causes and cover most of the different problems that affect the heart.

Are some dogs more at risk?

Because old age and the natural wear and tear on the body is a common cause of heart disease, it does mean that middle-aged and old dogs are more at risk of having heart disease compared to younger dogs.

In the case of mitral valve disease specifically, 10% of dogs between the age of 5 and 8 years old are affected by heart disease, the percentage climbs as a dog ages. 20-25% of dogs between the age of 9 and 12 and 30-35% of dogs older than 13 will develop MVD.

Meanwhile, certain sizes and breeds of dog are more at risk of developing specific heart diseases. For example, mitral valve disease commonly affects smaller breeds and is rarely found in big dogs. Amongst these smaller dogs, Cavalier King Charles Spaniels, Dachshunds, Chihuahuas, Papillons, and Poodles are more at risk of developing MVD than most.

It should be noted that crossbreed dogs are not immune to these problems. Hybrid breeds like the Cavapoo are still at risk of developing heart disease because their parent breeds of Cavaliers and Miniature or Toy Poodles are both prone to MVD and cardiac issues.

Cavalier King Charles Spaniels are more at risk of cardiac disease compared to other breeds, and MVD is a particular concern, affecting more than half of all Cavs by the age of five.

Meanwhile, big dogs are more likely to develop dilated cardiomyopathy and Dobermans, Great Danes, and Boxers are more at risk of having the condition. And brachycephalic breeds like Pugs, Bulldogs, and French Bulldogs are prone to a condition called pulmonic stenosis.

Signs and symptoms of heart disease in dogs

Regardless of what type of heart disease is affecting your dog, they all share similar symptoms. Dogs in the early stages of heart disease might show no obvious signs of illness, and more severe symptoms are associated with later stages of disease.

Some dogs might not display symptoms until their heart disease has advanced, which makes regular check-ups important because your vet can catch symptoms such as a heart murmur early. Murmurs can only be identified during an examination with a stethoscope. Noticing signs of heart disease in the early stages of illness is vital because it means treatment is more likely to be successful, and your pooch has a better chance of surviving and thriving with treatment.

Some of the signs and symptoms of heart disease in dogs include:

How to prevent heart disease

Sadly, there is no way to directly prevent heart disease from developing, especially as many acquired conditions are a result of natural wear and tear and the degeneration of your dog’s body with age.

Responsible breeding is a key part of preventing heart disease in puppies, especially in breeds prone to heart problems. Dogs should be screened to make sure they do not have conditions such as heart disease which they could pass on to their offspring, and only healthy dogs should be bred so the puppies are less likely to inherit a condition.

Reducing the risk

Once your dog is born, all you can do is try to keep them as happy and healthy as possible and prevent any illness which could damage their organs. For example, extreme heatstroke or severe dehydration can damage your dog’s internal organs, so making sure your pooch is always hydrated and kept out of the heat will prevent trauma.

Another step in keeping your pup healthy and preventing heart disease, and a host of other problems, is routinely vaccinating your pet and regularly using a parasite repellent.

Lyme disease bacteria can enter the heart and cause “Lyme carditis” which impacts the heart’s electrical activity and efficiency. Dogs contract Lyme disease after being bitten by an infected tick, but giving your pooch regular parasite medication should help to prevent any pesky parasites like ticks from biting your dog. You should also check your dog after they’ve been running through long grass, or during grooming sessions, to spot ticks and remove them as soon as possible which can prevent the spread of Lyme disease.

Heartworm is another cause of heart disease in dogs but thankfully, heartworm hasn’t yet been found in the UK. But, it can be found abroad so if your dog travels with you they might be at risk, but there is effective preventative medication that can keep them safe from these nasty parasites.

Gum disease has also been linked with a higher risk of heart disease and heart failure in dogs. Although gum disease is common in dogs, it can easily be prevented by brushing your dog’s teeth regularly. This will also prevent any problems caused by gum disease, including dental cavities, as well as getting rid of one risk-factor of heart disease in dogs.

Finally, obesity is a risk factor in dogs having heart disease, and obese dogs are also more likely to develop diabetes which can lead to heart disease. Being overweight puts additional strain on your pup’s heart and many obese dogs have high blood pressure and an elevated heart rate, because their heart has to work harder than normal to pump blood around the body. Obesity also impacts the ability of your dog’s heart to function and even changes their cardiac structure.

Plus, gradual weight loss and maintaining a normal weight will put less pressure on your dog’s heart and vets normally advise that your dog should lose weight to ease the strain on their heart.

Exercise and a healthy diet help

You should make sure you are feeding your dog a healthy diet and exercising them regularly. Exercise helps to keep extra weight off and strengthens the muscles in their body, including their heart muscle. Making sure they get all the nutrients they need will keep their body healthy and able to heal and repair itself. A balanced diet with high-quality protein will also prevent vitamin deficiencies, such as taurine deficiency, which could cause heart disease.

It’s important not to downplay the vital role food plays in your dog’s heart health, because nutrition is a cornerstone of treating and managing heart disease in dogs (we’ll discuss this in detail in “the best dog food for heart disease in dogs”).

There appears to be a link between diet and a heart disease called dilated cardiomyopathy, which is currently under investigation in America. However, no direct cause has been found. There is speculation that the culprit is a nutritional imbalance of some form, and the majority of reported cases involve grain-free, legume-rich diets. It’s also been proposed that it could be caused by the poor digestibility or a lack of taurine (an amino acid from protein) in certain commercial dog foods, indicating the increased importance of high-quality protein in dog food, rather than just “high protein”.

Diagnosing heart disease

If you suspect your dog is suffering from any sort of illness you must take them to the vet for an examination. Many of the symptoms of heart disease are similar to other illnesses, which is why it’s better to be safe than sorry and always get an expert opinion if your pooch is unwell.

Your vet will discuss your dog’s symptoms with you alongside environmental factors such as diet, exercise, and lifestyle. They will also perform a physical examination of your pet to check for any other symptoms or possible illness. During the exam, they will listen to your dog’s heart with a stethoscope to check for any abnormal rhythms to their heartbeat, whether it’s fast or slow, and if they can hear a heart murmur.

A heart murmur is often harmless in itself, but it can be one of the earliest indications of heart disease. It’s an odd sound your dog’s heart makes and is different to the usual “du-dun '' sound of their heartbeat. Murmurs are often described as a whooshing sound, caused by blood moving through the heart turbulently.

Your vet might X-ray your dog’s chest to get an inside look at their heart. Heart disease like dilated cardiomyopathy causes the heart to become much larger than normal, so getting an inside look helps your vet to understand exactly what’s going on with your pup’s ticker. As well as an X-ray, they might perform an echocardiogram, which is an ultrasound of the heart and also allows them to take an inside look at the organ.

Another test your vet might conduct is an electrocardiogram, which measures the electrical activity of your dog’s heart to see whether it’s normal or not.

Finally, your vet might ask to carry out blood and urine tests, which won’t diagnose heart disease but they will help to rule out other conditions that could be impacting your pooch’s heart.

Treatment for heart disease in dogs

The treatment for heart disease in dogs will vary according to your dog’s symptoms and the type and severity of disease that they are suffering from.

Sadly, there is no complete cure for heart disease and it will get progressively worse. The aim of treatment is to slow down the progression of the disease and to reduce your dog’s symptoms so they can live as long, happy, and comfortable a life as possible.

In the early stages of heart disease, there may be no need for treatment. Some dogs with mild heart disease can even carry on their entire life without any need for treatment, but your vet will want to monitor your dog and carry out routine check-ups to make sure their disease is not progressing, in which case they might need medication.

Heart disease in dogs can often be effectively managed using medication, which will control your dog’s symptoms and slow the progression of their condition and prevent it from advancing into heart failure. In most cases, dogs can live a happy, normal life with the help of medication, and maybe some exercise and diet tweaks.

It’s important to remember that medication is not a complete cure and your dog’s heart disease will not go away completely and your dog will probably need to have daily medication for the rest of their life. Even on medication, their condition can still progress and worsen over time.

However, your dog’s condition is only guaranteed to get worse if they have no treatment at all, and their life expectancy will be much shorter if nothing is done to help them.

What medications are given for heart disease

Many dogs will be treated with a drug called pimobendan, which strengthens the force the heart can pump with, and increases the cardiac output, which is the amount of blood the heart pumps. It’s very effective and most dogs show improvement within a week, it can decrease heart enlargement within a month, and it increases a dog’s life expectancy. However, pimobendan isn’t suitable for all dogs to have, and it cannot treat every kind of heart disease.

Some dogs might be prescribed ACE inhibitors, which reduce the stress on the heart by relaxing the veins and arteries, making it easier for blood to be pumped around the body and reducing blood pressure. Other dogs may need beta-blockers to reduce their heart rate, or digoxin to control an abnormal heart rhythm

Other treatments for heart disease in dogs

Your dog may require other medicines depending on the symptoms they have. For instance, cough suppressants may be given because dogs with heart disease often have a continuous cough which is often quite uncomfortable and irritating for your furry friend.

Another example would be a prescription of diuretics to combat ascites, or fluid retention. This is because the heart can’t pump blood as well as it should so the kidneys don’t get as much blood as they need to work effectively, resulting in fluid retention. If your dog is suffering from fluid on their lungs as part of an advanced stage of heart disease or failure, diuretics can help to reduce the amount of retained fluid and let them breathe easier.

In rare cases, your dog may need surgery as part of their treatment. This is however only appropriate for dogs who are suffering from a physical defect in their heart.

Your vet will also advise you on lifestyle changes you should make for your dog, which will include diet changes and it will often include avoiding high-intensity exercise.

The best dog food for heart disease in dogs

Nutrition is key in helping to treat heart disease in dogs. Not only will eating a healthy, balanced diet help to keep your dog in good overall health, but there are also a number of vitamins and supplements they can eat that will help to control their symptoms and manage their condition.

It’s been proven that feeding a dog the right levels of dietary nutrients can help them to live longer and improve their quality of life by reducing their symptoms. Nutrition isn’t all though, as many dogs lose their appetite when suffering from heart disease, so making sure their food is appetising and tasty to encourage them to eat is also just as important in their recovery.

You should always talk to your vet or a canine nutritionist about what foods might help to keep your pup healthy. They can also advise you on what supplements might benefit your dog. Some supplements can interfere with medication though, so make sure you tell your vet about any herbal remedies, medicines, or supplements your dog has.

What nutrients help to manage heart disease?

One of the most important nutrients you can give your dog is omega-3. Omega-3 supplementation has been shown to significantly increase the survival time of dogs with heart disease and it reduces their risk of sudden cardiac death. Omega-3 also helps to reduce inflammation in the heart, and it might be able to help control abnormal heart rhythms.

Oily fish is a fantastic source of omega-3, but it can also be found in other fish like cod. Many green, leafy vegetables also contain a good dose of omega-3, as well as many nuts and seeds (be careful though, as several kinds of nuts are toxic to dogs).

Antioxidants can also help to reduce inflammation and are an important part of treating heart disease in dogs. Vitamin E, in particular, is a powerful antioxidant, but it has also been proven to help in the treatment of heart disease. You can find antioxidants in many fruits and vegetables like mango and spinach as well as salmon and peanut butter.

It’s also been found that vitamin D deficiencies are linked with the advanced progression of heart disease and a poor prognosis in humans, and it appears to be the same with dogs. Vitamin D can be found in all kinds of food like oily fish (which is also packed full of omega-3), red meat, and eggs.

Fish, meat, and eggs are also good sources of L-carnitine and taurine, which are also important nutrients to help prevent and treat heart disease in dogs. Amino acids like taurine are found in meat, but they are destroyed by harsh food processing such as extrusion which is used to make kibble. As mentioned earlier, high protein food doesn’t equal the best food, because the quality of that protein could be poor and your dog might digest and absorb very little of it, as is the case with lamb meal. Instead, their food should contain a high-quality whole protein source that their body can digest easily and absorb, meaning they get more of the nutrition and amino acids they need.

Pure is healthy, wholesome dog food, that only ever uses human-quality protein that’s good enough for you to eat, as well as carefully chosen whole foods like salmon oil, fruits, and vegetables that provide all the nutrients your dog needs to stay healthy. We also tailor our food to your dog and their individual needs, taking into account any conditions such as heart disease and what will benefit them.

We carefully remove the moisture from our ingredients, which preserves the nutrients whilst naturally preserving your dog’s dinner without the need for any nasty additives. Our process is gentler than cooking because it only requires temperatures of up to 60℃, whilst you would roast a chicken in the oven at at least 180℃!

You can also change the consistency of your pup’s food by changing how much water you use, and try using warm water which can make it more appetising and encourage your dog to eat, which is an important part of recovery.

Home remedies for heart disease in dogs

There are no effective home remedies for heart disease in dogs. Home remedies like dietary changes and nutritional supplements will be the same as the ones your vet will advise you on, and what we have discussed above.

The only other possible home remedy you might find would be a dandelion tincture, which is a natural diuretic. Not all dogs with heart disease need a diuretic though, so you must discuss with your vet if it will even help your dog. It has been used effectively in humans, but there hasn’t been much study on its use in dogs.

Just because a remedy is natural doesn’t mean it is safe or effective. For example, a home remedy for hypertension in humans is snakeroot or milkweed, however, you cannot give this to your dog because these plants are toxic to dogs.

Herbal remedies and supplements can also interfere with medications and impact their effectiveness, so you should never try to give your dog something alongside their medicine without discussing it with your vet first. It’s also important to never try and treat your dog at home without consultation from a professional, because you might do more harm than good by accidentally giving your dog something that could be toxic or that could worsen their condition.

This is especially true in the case of heart disease, where the treatment your dog needs will vary dramatically depending on the cause. Additionally, the medicines used to treat one kind of heart disease aren’t always safe or effective against other types of disease.


The prognosis for a dog with heart disease is difficult and will vary depending on the type of disease your dog is affected by, the severity of their condition, and how well they respond to treatment. However, most dogs can live happily for many years with heart disease as long as they receive treatment.

However, heart disease can never completely get better and it can still worsen over time even with treatment, but medication can dramatically improve your dog’s quality of life and provide a few more years of happiness with your furry friend.

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