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The topic of heart disease in pets is often a sensitive matter, not least because of its complex nature. There are a whole number of different types of heart diseases, with different signs and symptoms, as well as different diagnosis and treatments. In this article, we help you to get to the bottom of animal heart disease, focusing on some of the most common heart diseases in pets.

So, what are some of the most common heart diseases in pets? Five of the most common heart diseases that vets see in pets include Valvular Degeneration, Dilated Cardiomyopathy (CDM), Hypertrophic Cardiomyopathy (HCM), Heart Arrhythmias, and Congenital Heart Disease.

Read on to learn more about common heart diseases in cats and dogs.

If you have concerns over you pets health please book an appointment online for the soonest availability you can or call us to discuss in more detail,

What is the Difference Between Hereditary, Congenital, and Acquired Heart Disease?

We all know that heart disease is critical for our pets; if a heart disease interrupts your pet’s normal cardiovascular function, their entire body can be compromised. But, how much do you know about the different types of heart disease?

Heart disease in pets can be hereditary, congenital, or acquired. This means that the disease could be genetic, transmitted from their parents, that they were born with the disease or defect, or that the disease developed throughout your pet’s life.


Hereditary heart diseases are genetic conditions that are passed on via the genes, from parent to child. These conditions can be present at birth, but sometimes can go undetected until later in life (although, not always). Therefore, if you know that the parent has a heart condition, it’s important to watch for signs of it in your pet from a young age.

What’s more, some conditions, such as obesity, can increase the risk of a hereditary condition developing. Think of it like Type 2 Diabetes in humans; whilst an individual is predisposed to the condition genetically, if that individual is overweight and has a poor diet, the risk of developing Type 2 Diabetes is much higher.


Congenital heart diseases are similar to hereditary conditions, but are not the same. They are developmental diseases so congenital heart diseases are not passed from parent to child. Instead, they develop whilst your pet is in the womb, and can be caused by a number of factors, including genetic defects, environmental conditions, infection, poisoning, medication taken by the mother, or poor maternal nutrition.


Acquired heart diseases are those that are not present at birth, and instead develop throughout your pet’s life. Examples of acquired heart diseases in pets include, Degenerative Valve Disease, Cardiomyopathy, and Myocarditis.

Heart disease is a common problem in both dogs and cats. In the beginning the body will adjust to compensate for the disease and so signs of disease are hard to detect. However, as the disease progresses into clinical heart failure, deterioration in their health is often detected. This is usually more quickly apparent in dogs who may show signs of exercise intolerance on their walks whereas cats may go a lot longer without any abnormality being evident.

Common Acquired Heart Diseases in Cats

Cats are at risk of a number of acquired heart conditions that may develop throughout their lifetime. The most common acquired heart diseases in cats include:

  • Hypertrophic Cardiomyopathy (HCM)

    Hypertrophic Cardiomyopathy is the most commonly diagnosed heart disease in cats. The condition is a result of the thickening of the left ventricular muscle (the wall of the big chamber that pumps blood around the body). As the muscle thickens (inwards more than outwards), the area for blood to fill gets smaller. The heart, therefore, has to beat faster and harder to output the same volume of blood. This causes a vicious cycle which makes the condition worse. Other changes elsewhere in the heart can then increase the risk of Congestive Heart Failure and blood clots.

    Unfortunately, cats are very good at hiding illness, and HCM can often go unnoticed for a long time; cats rarely show signs of HCM until Congestive Heart Failure occurs, or blood clots develop.

    As such, regular veterinary check-ups are vital for heart health in cats. Make sure to keep on top of your cat’s physical examinations so that your vet can check for signs of HCM.

  • Heart Arrhythmias

    Heart Arrhythmias are abnormal heart rhythms that are the result of electrical impulses within the heart failing to initiate properly, follow the correct pathway, or move through the entire system properly. Such conditions include:

    • Tachycardia – increased heart rate
    • Bradycardia – decreased heart rate
    • Premature Ventricular Contractions
    • Heart Block
    • Atrial Fibrillation

    Common signs of Heart Arrhythmias include weakness, lethargy, exercise intolerance, or even collapse. It can be difficult to recognise these symptoms as heart disease, but it’s important to recognise that, regardless, they aren’t normal. Consult your vet immediately if you think something is out of the norm with your cat, and they will be able to perform diagnostic tests to get to the bottom of it.
    In cases of Heart Arrhythmias, an Electrocardiogram may be used to evaluate your cat’s heart, or they may recommend that your cat wear a Holter Monitor for a period of time to get a bigger picture of your cat’s heart health.

Signs of Heart Disease in Cats

We understand that it can be difficult to notice symptoms of heart disease in cats, when they’re so good at hiding illness. However, it’s important to watch out for symptoms of irregularities and illness in your cat anyway so that you get on top of whatever is causing their illness.

Here are some common signs of heart disease in cats:

Loss of Appetite

Loss of appetite doesn’t automatically mean heart disease, but it is a sign that something isn’t quite right, and could be a symptom of a number of feline conditions.

Weight Loss

Weight loss could be the result of whatever is causing your pet’s loss of appetite, but it can also be a sign of heart disease. If you notice that your cat has recently lost a lot of weight, consult your vet immediately; not only is it a common sign of heart disease, but of a number of other serious conditions.


Again, lethargy could be a symptom of any number of feline conditions, however if your cat is either extremely lethargic, or if their lethargy occurs in conjunction with another symptom of heart disease, contact your vet immediately.

Breathing Problems

Pay attention to your cat’s breathing; if they have an increased respiratory rate or increased effort to breathe, it’s time to contact the vet.

Sudden Collapse

If your cat is otherwise healthy and suddenly collapses, consult your vet as soon as possible. This could be a sign of a heart condition, or another serious condition.

Sudden Hind Leg Paralysis

Sudden hind leg paralysis, and pain in the hind leg(s) may be a sign of a blood clot. This is a very serious matter and you should contact an emergency veterinarian immediately.

Evidently, many of these signs are those that as humans, we associate with old age and so may not take too much notice off until they are more advanced, but it is always worth having a chat with your vet if your pet shows persistent changes in their behaviour, appetite or usual exercise. Cats are a little more challenging but older cats that spend more time sleeping, lose weight or who breathe more rapidly should certainly have a check up with the vet.

Common Acquired Heart Diseases in Dogs

Dogs are at a larger risk of developing heart disease throughout their life than cats, some of which include:

  • Degenerative Valve Disease (DMVD)

    Degenerative Valve Disease, also known as Endocarditis, Valvular Regurgitation, and Valvular Insufficiency, is the most common acquired heart disease in dogs, and is thought to account for around 75% of all canine cardiovascular diseases.

    Myxomatous Mitral Valve Disease (MMVD) occurs as a result of degeneration to the heart valves that lay between the atrium and ventricle on both the right (Tricuspid Valve) and left (Mitral Valve) side of the heart. However, the left (Mitral) valve is typically more severely affected.

    This degeneration process causes the valves to become abnormally thick, and develop a lumpy appearance, which stops them from forming a tight seal between the atrium and ventricle when the heart is pumping. In turn, this causes the heart to leak backwards, or regurgitate.

  • Dilated Cardiomyopathy (DCM)

    Dilated Cardiomyopathy is the leading cause of heart failure in larger breeds of dogs such as Boxer Dogs, Doberman Pinschers, Great Danes, and St Bernards. Smaller breeds rarely develop DCM.

    The disease is defined as degeneration of the heart muscle, where the muscle becomes thinner. The blood pumping inside these thin muscles causes them to stretch, resulting in a much larger heart.

    DCM typically develops slowly and subtly, with symptoms including rapid breathing when resting or sleeping, restless sleep, coughing or gagging, weakness, reduced physical ability, weight loss, depression, and a decreased appetite.

  • Mitral Valve Disease (MVD)

    Mitral Valve Disease is a common condition in smaller breed dogs such as Cavalier King Charles Spaniels. It usually occurs due to degeneration of the valve leaflets, instead of being smooth the valves develop nodules which impair the movement and closure of the valves during the normal heart cycle. This in turn makes the valve leak blood in the wrong direction, which makes the chambers of the heart become dilated and pumping of blood inefficient.

Signs of Heart Disease in Dogs

Just like in cats, it can be difficult to pinpoint your dog’s symptoms to a specific condition. However, know that it is important to recognise what is abnormal for your dog, and their known health condition.

Here are a few signs of heart disease in dogs:

Unusual or Excessive Coughing

Dogs with heart disease typically have an ongoing cough that lasts for more than a few days. This may be a result of heart enlargement or heart disease impacting on lung function.

Whilst not always a sign of heart disease, any persistent cough should be checked by your vet.

Fainting or Collapse

When the heart begins to function improperly, this can have a knock-on effect on other organs. Vital organs, such as the brain, can become deprived of oxygen as a result of decreased heart function, leading to fainting, or complete collapse.

Difficulty Breathing

Another typical sign of heart disease in dogs is difficulty breathing. You may notice that they breathe more rapidly, or with more effort.

Fatigue or Lethargy

Dogs with heart disease will typically tire much quicker than healthy dogs, both during exercise, and when at home. You may find that they sleep more often than usual.

Behavioural Changes

Any noticeable behavioural changes can be cause for concern, and may be a sign of any number of conditions, however, dogs with heart disease typically show behavioural changes such as loss of appetite, isolation, and a reluctance to play as normal.

What Breeds of Cats & Dogs are Most Commonly Affected by Heart Disease?

Some breeds of cats and dogs are naturally more susceptible to heart disease. Some of the most common breeds are listed below.

  • Cats

    • American Shorthair
    • Maine Coon
    • Persian
    • Siamese
    • Ragdoll
    • Sphynx
  • Dogs

    • Dobermans
    • Boxers
    • Irish Setters
    • German Shepherds
    • Great Danes
    • St Bernards
    • Irish Wolfhounds
    • Terriers
    • Cavalier King Charles Spaniels
    • Dachshunds
    • Miniature and Toy Poodles

Investigation and Diagnosis of Heart Disease in Pets

Once you spot the signs of heart disease in your pet, your vet will want to conduct a number of diagnostic tests to both confirm the disease, and to determine its severity. Heart murmurs, whilst not an indication that treatment is required immediately, will always benefit from medical investigation as to the cause of the murmur. In puppies and kittens especially it could be a sign of a congenital condition that may cause significant health problems for the animal. In older dogs and cats, it allows a benchmark measure for future changes to be compared against and give owners an idea of progression of the disease. Some of these medical examinations include:

Electrocardiogram (ECG)

An ECG is a simple test that is used to check the rhythm of your pet’s heart. Sensors are attached to the skin and detect the electrical signals produced by the heart when it beats.

Chest X-Rays

A chest X-Ray produces images of your pet’s heart and lungs, as well as showing their skeleton. It can detect a number of different conditions to the heart and lungs without the need for invasive tests.


An Echocardiogram is a type of ultrasound scan used to look at the heart and blood vessels nearby. It is used to both detect and monitor heart conditions by checking the structure of the heart, analysing how blood flows through the heart, and assessing the pumping chambers of the heart.

Blood Pressure

Blood pressure tests for pets are conducted the same way as for humans, with an inflatable cuff placed around your pet’s paw or tail. It is non-invasive and non-painful and can be done in a calm and conscious patient.

Knutsford Vets has your animal’s health at heart

Treatment for Heart Disease in Pets

There are a number of different treatments available for pets with heart conditions, but most conditions are treated with medication, or by controlling your pet’s diet. That said, the treatment that your vet recommends will depend entirely on the condition that your pet has, and its severity.


Some heart conditions will not require treatment in their early stages, however will need regular monitoring and checkups.


Generally, oral medications are used to help the heart work efficiently and to slow further progression. Medication will not necessarily cure your pet’s heart condition but it will help to reduce the symptoms. Please be aware that even with medication, many heart conditions will become progressively worse over time.

In cases where the heart disease is caused by another condition, we find that treating that condition will often form part of the overall strategy, and may help to reduce the symptoms of the heart condition.


In some cases, monitoring and changing your dog’s diet may be beneficial to their condition. It’s unlikely to cure their heart disease, but may help to improve their quality of life and reduce symptoms. However, the most important factor to consider when changing your pet’s diet is that they remain at a healthy weight.

For underweight pets, consider a diet rich in quality proteins, whilst for overweight pets, consider reducing the amount of fat and carbohydrates they consume. For all pets with heart disease, you should aim to reduce the amount of sodium in their diet as excessive consumption of sodium can contribute to a buildup of fluid in the chest that may influence coughing and breathing problems.

On the other hand, it is recommended to include the following nutrients in your pet’s diet:



Vitamin E

Enzyme Q10

Before making any changes to your pet’s diet, however, consult your veterinarian to ensure that this is both healthy, and beneficial to your pet’s specific needs.

Useful Apps to Monitor Breathing Rate

If your pet has heart disease, your vet may ask you to monitor various vitals at home. But how do you do that? Luckily for us, we live in the 21st Century, where there is no shortage of apps, tools and gadgets to help us monitor health, and this doesn’t stop with humans – there are now apps available to help you monitor your pet’s health.

Cardialis App

If you are an Apple device user, you will be able to download the Cardialis app from the App Store, which allows you to measure your pet’s respiratory rate, and email the data straight to your vet. It couldn’t be easier. You can also download the app from Google Play for Android devices.

This data will allow both you and your vet to monitor your pet’s health, and quickly identify when something isn’t right so that you can get on top of it much faster. The app is incredibly user-friendly and tells you exactly what you need to do with a helpful video.

When you open the app, a clock will appear. Simply tap the relevant icon each time your pet breathes. After 30 sections to one minute, it will have recorded how many breaths your pet takes per minute, records that data, and charts it. If your pet’s heart rate is too high, it will alert you to contact an emergency vet immediately.

Download the Cardialis app via the Apple App Store or the Google Play Store.

How to Monitor Your Pet’s Heart Disease Without an App

Of course, you can always monitor your pet’s breathing manually, and record the information yourself with pen and paper, or by charting it on a spreadsheet.

The breathing rate for a normal dog or cat at rest is usually less than 30 breaths per minute – and it can be as low as 12 breaths per minute in some animals. Simply count how many breaths they take in the space of 60 seconds, during a resting period. Don’t try to monitor this when they are panting.

It’s also important to measure their breathing effort – how much effort does it take to breathe? You can evaluate the breathing effort by watching the motion of the ribs and the belly muscles with each breath.

  • If your pet is breathing with more effort you may notice:
  • Stomach muscles moving more forcefully with each breath
  • Chest and ribs moving further with each breath
  • Breathing with an open mouth
  • Standing with their legs in a wide stance
  • Have their neck outstretched

Other Useful Apps

  • Vetoquinol has developed a web-based app to help you monitor your pet’s sleeping respiratory rate at home and give an indication of the status of their medical condition. This is particularly useful for Congestive Heart Failure.
  • Resting Respiratory Rate (RRR) tracks your pet’s resting respiratory rate, compares the data over time, and can deliver the information directly to your vet.

Heart Disease Treatment with Knutsford Vets

Knutsford Vets offers a Veterinary Cardiology service to help spot the signs of heart conditions in pets. Our dedicated team can identify a range of problems including birth defects, problems with the valves, and enlarged heart chambers or thickened heart muscle.

Heart disease is a serious health condition for pets, that’s why we have a visiting veterinary cardiologist and a range of diagnostic equipment that our experienced vets can use to diagnose a condition. If you think that your pet may have heart disease, book an appointment with us immediately, and we’ll help to get to the bottom of the problem.

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