What are the signs of heart disease in dogs?

A vet inspecting a dog on a vet's table

From breeds small enough to fit in a handbag to large enough to stand shoulder-to-shoulder with a pony, dogs are one of the most diverse species on the planet. And while they come with a fantastic variety of coats, head shapes, snouts and behaviours, they all have one thing in common. They have a big heart – metaphorically speaking, at least.

But while they all have a personality of their own and they all make loyal companions, they can suffer from heart problems just as their human guardians do. Responsible owners need to be able to spot the signs of such health problems before it’s too late. Insurance for your pet can help cover the costs if treatment is needed.

Dog heart versus human heart

In both dogs and humans, the heart is one of the most vital internal organs. Indeed, a defective or improperly formed heart can lead to a wide range of health problems, and can have serious implications for your future life together.

As mammals, our hearts have a lot in common in terms of their functions and structures, but there are also a number of notable differences.

The heart forms the core of our circulatory systems and pumps oxygenated blood around our bodies.

In terms of structure we both have four chambers and four valves in the heart that function in a very similar way. Among the subtle structural differences is the number of pulmonary veins. We have four to five while canines have between four and eight.

There is a huge range of heart sizes in dogs determined by the particular breed – a feisty but tiny Chihuahua is going to have a smaller heart than a Alaskan Malamute! Indeed, very large dog breeds might well have a heart around the size of a human’s, or even larger.

One of the most obvious differences between a canine heart and that of their human packmate is the rates at which they beat. While resting a human’s normal heart rate ranges from 60 to 100 beats per minute.

However, an adult dog's resting heart rate ranges between 60 to 160 beats per minute. Larger breeds will have heart rates towards the lower end of the spectrum, while toy breeds and young puppies will reach the higher end.

A man laying on a bed using his mobile phone as a dog licks his face

Heart disease in dogs

While heart disease is a well-known cause of death in humans, the same cannot be said for our four-legged friends. Indeed, a study by the Royal Veterinary College found that heart disorders were recorded in only around 6% of dogs in a random sample – far lower than that seen in humans.

Human owners, in particular, worry about the onset of coronary artery disease but this condition doesn’t tend to afflict our canine friends. Instead, they can develop a range of other cardiac problems.

These problems can either be congenital or acquired, although the majority of cases are considered to be acquired.

Congenital conditions

As the name suggests congenital conditions are present from birth and can be down to a breed’s susceptibility to a condition. Or where a condition has been passed down from the parents. Common types of congenital conditions include:

Congestive heart failure

Often caused by a problem with the valves in either the right or left side of the heart, this condition means the dog’s heart can no longer pump the right amount of blood throughout the body. It can also lead to an increase in fluid and pressure within the heart. Fluid can then leak into the lungs and affect your dog’s breathing. Unfortunately, this condition may take years to become noticeable.

Canine Dilated Cardiomyopathy

Typically seen in breeds like Boxers, Doberman Pinschers, Cocker Spaniels, and Great Danes this disease weakens the heart’s muscles and reduces its ability to pump blood through the body. While this condition can be genetic, nutrition and other infections might also play a part.

Pulmonic Stenosis

A malformation in one of the heart valves obstructs blood flow between the heart and the lungs. The defect is usually found in Bulldogs, Boston Terriers, Boxers, Jack Russell Terriers, Samoyeds, Newfoundlands, and Labrador Retrievers. The severity of the condition can range from mild (where no signs are ever detected through life) to severe (where there’s an increased risk of heart failure and even death).

Acquired conditions

Most often seen in middle-aged and older dogs, acquired conditions typically develop over time and are the result of normal wear and tear, and aging. Below are some of the more common types of acquired conditions.

Canine Valvular disease

This condition occurs when the heart valves weaken and begin to leak. More usually found in the left mitral valve rather than the right tricuspid valve, both result in blood leaking back into the previous chamber and more work for the heart. It more commonly affects smaller breeds of dog over five years of age.


An abnormality in the rhythm of the heart can affect the speed, strength or regularity of heart beats. It occurs when a problem develops within the dog’s natural electrical system that interferes with the signals it’s sending to the heart.

Pericardial effusion

When the pericardial sac surrounding the heart fills with fluid. This interferes with the heart’s ability to pump effectively. This condition has a number of possible causes including tumours, inflammation caused by infection and trauma.


While not present in the UK yet, if you’re planning on taking your dog abroad on holiday with you, you need to factor in the risk of canine heartworm.

This parasite, which is spread by mosquitoes, can cause serious and potentially fatal disease in your dog. It’s common in Australia, America, Spain, Italy and southern France.

However, recent climatic changes have allowed the parasite to spread closer to the UK, and it has recently been reported in Germany and elsewhere in northern Europe.

Always speak to your pet insurance provider to make sure your beloved pooch is protected when travelling abroad.

A vet using a stethoscope to check a puppy's heartbeat

Common signs of heart disease in dogs

There are many types of heart diseases that can affect dogs, but most share common signs to alert owners to a problem. Look out for the symptoms that could indicate something more serious:

Frequent coughing

If your dog develops a persistent cough that doesn’t go away within a few days then it could be a sign of heart disease.

If the heart isn’t pumping efficiently enough then fluid could begin to accumulate in the lungs and cause a cough.

Some heart diseases can also lead to an enlarged heart which presses on airways and causes coughing. In some cases, your dog might have a low-pitched cough that sometimes leads to gagging.

Fainting or collapsing

If a heart isn’t functioning properly then vital organs such as the brain can become deprived of oxygen. If this happens then your faithful friend could faint or collapse, particularly after exercise or a coughing fit.

Breathing difficulties or shortness of breath

Watch out for rapid or more forceful breathing. Particularly if the dog sits or stands for long periods with their legs wide apart and with their neck stretched out. They could be struggling to breath.

Tired and lack of energy

Tiring out more quickly on walks and during exercise or sleeping more than usual are also worth investigating with your veterinary professional. The great thing about pet insurance is you can investigate early, confident you won’t be hit with an unexpected bill.

Behaviour change

Poor appetite, noticeable weight gain or loss, isolation, and a reluctance to play or engage in previously pleasurable activities are all signs your dog could be having health problems.

All our pet insurance policyholders have access to a free 24-Hour Vet Helpline they can call at any time for advice. All calls are handled by registered veterinary nurses with a minimum of three years of practical experience.

A dog laying down outside with its chin on the floor looking sad

How vets diagnose heart disease in dogs

Unfortunately signs of heart disease are similar to many of those seen with other diseases such as arthritis, seizures and chronic lung disease.

To narrow down the diagnostic possibilities, your vet will consider your dog’s health history and perform a series of tests.

 Tests helpful in heart disease diagnosis include:

  • Stethoscope exam - To reveal heart murmurs and the presence of fluid in the lungs.

  • Chest X-ray – X-rays can reveal heart enlargement, and are one of the best ways to assess fluid build-up in and around the lungs.

  • Electrocardiogram (ECG) – An ECG can detect an arrhythmia.

  • Echocardiogram – An echocardiogram is an ultrasound of the heart. This non-invasive test can provide important information not only about any disease, but also helps assess how effective any treatment is.

  • Blood and urine tests – These can reveal heartworms and the condition of other internal organs such as the kidneys.

A heart condition may not be obvious in the early stages and some of these tests can be expensive. Having pet insurance in place means that if you’re in any doubt about your dog’s health you’ll get help as soon as you need it without financial worry.

Treatments for heart disease

Because heart disease is caused by many different conditions there are many different treatments available. Unfortunately, heart disease cannot be cured completely but it can be treated if it’s caught early enough.

Common treatments include prescription medicines and supplements, changes to diet, and even surgery (although that is rare). However, any treatment needs to be with the guidance of your veterinary professional.

How to prevent heart disease

Preventing heart disease in dogs is difficult, especially as some dogs are born with a susceptibility to some conditions. But there are always steps that a responsible owner can take to help their dog live a long and healthy life.

Feeding your pooch a healthy diet is a great place to start. Vet charity PDSA recommends feeding your dog a high-quality, complete dog food.

These complete diets contain all the nutrients your dog needs, in the perfect amounts. However, always follow the recommended feeding guidelines and weigh out your dog’s food to make sure they’re eating just the right amount.

Regular exercise is also a key part of having a healthy and happy dog. However, if your trusty pal has been diagnosed with heart disease, be careful of too much activity and always monitor them afterwards for signs of distress.

There are many breeds that are prone to heart disease, so be aware of the symptoms that can alert you to heart disease. Remember, the sooner you catch it, the better the chances for treatment.

Two dog food bowls, one with kibble and the other containing raw meat and vegetables

Are dogs good for your heart?

While you can do a lot for your dog’s heart it seems like they can also work wonders for yours too, recent studies claim.

Owners have long known that our furry friends have an incredible ability to help our mental wellbeing, reduce anxiety and loneliness. However, it seems like they could also have a positive effect on our physical health with owners 65% less likely to die after a heart attack.

Meanwhile, scientists in Sweden say that owning a dog reduces the risk of death by an incredible third for those living alone and the risk of heart disease by 11%!

Protect your pup with Purely Pets

With dogs being so valuable to our own health we really can’t put a price on keeping them healthy and safe from harm.

In addition, vet bills can be costly if your dog gets injured or picks up an illness while you’re out and about, so it’s best to have pet insurance coverage in place from an early age.

With pet insurance from Purely Pets you can give your dog the protection they deserve at a level of cover to suit any budget.

Vets’ fees for accidents, illness or both can be covered from between £1,000 and £15,000, depending on the level of lifetime cover you choose.

Policyholders have access to our 24-Hour Vet Helpline and an online policy management portal so you can manage your documents at a time that suits you.

Get a pet insurance quote today.

Policy benefits, features and discounts offered may very between insurance schemes or cover selected and are subject to underwriting criteria. Information contained within this article is accurate at the time of publishing but may be subject to change.

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