A dog cuddling a heart soft toy

Types of heart diseases

Congestive heart failure

Congestive heart failure is when the heart has trouble pumping blood around the body. This often results in a build-up of fluid and increase in pressure in the heart, which may even leak into your pet’s lungs. Congestive heart failure can take many years to present itself so you may not even know that your pet has it.

Canine dilated cardiomyopathy

Canine dilated cardiomyopathy affects the muscles of the heart. This can cause a lack of pressure, meaning that not enough blood will be pumped around the body. While the condition may be genetic, and therefore passed down from parent to pup / kitten, it can also be related to nutrition or via an infection. Some dog breeds, such as Great Danes or Boxers, may have a greater genetic predisposition to canine dilated cardiomyopathy than other breeds.

Pulmonic stenosis

Pulmonic stenosis is an obstruction that affects blood flow between the right ventricle of the heart to the pulmonary artery of the lungs. It may show no symptoms in mild cases, although moderate to severe cases may lead to fatigue or an intolerance to exercise. Some breeds, such as Bulldogs, Boxers or Jack Russells, are more genetically predisposed to pulmonic stenosis than other dog breeds.

Around 95% of heart disease in pets are acquired, so it’s helpful to understand the different types of acquired heart disease:

Canine valve disease

Canine valve disease is a weakening of the valves in the heart, which can cause leaking. This can lead to a reduced amount of blood being pumped through the body. Eventually, canine valve disease may lead to heart failure.


Arrhythmias are irregular heartbeats (slow, fast, or skipped) caused by issues with the electrical activity of the heart. Arrhythmias can lead to weakness, or loss of consciousness in serious cases.

Pericardial disease

Pericardial disease is an abnormal accumulation of fluid in the sac that surrounds the hearts, which can then affect your pet’s heartbeat. Pericardial disease can lead to low blood pressure and poor circulation, as well as congestive heart failure.

Symptoms of heart disease in pets

There are many symptoms to watch out for which could indicate that your pet is suffering from a form of heart disease.

  • Cough is a common symptom. While most coughs will go away after a few days, a persistent cough may indicate a more serious issue.
  • Difficulty breathing may be related to above, or it may include other symptoms such as rapid or forceful breaths.
  • Weight loss, particularly if it occurs rapidly and unexpectedly.
  • Fatigue, as pets suffering from heart disease may not feel like exercising and may sleep more than usual.
  • Fainting/collapse, as organs (such as the brain) may become deprived of oxygen if the heart is not pumping blood effectively.
  • Bloating of the abdomen, which may result from fluid building up in the belly.
  • Change in behaviour, particularly if it includes one or multiple of the above symptoms.

Please keep in mind that the above symptoms are also seen with other conditions which aren’t related to heart disease, so consulting your vet is the best idea.

When to see your vet about heart disease?

If your dog or cat displays the above symptoms and you are concerned for its health, it is always best to consult with a vet. There are many tools available to help diagnose issues, such as:

  • X-rays, which are useful for seeing the size of your pet’s heart or to check for fluid build-up.
  • Electrocardiograms (ECG), which can monitor the electrical activity of your pet’s heart to check that it beats regularly. A Holter monitor is a device worn around the chest over several days to detect issues with the heart.
  • Echocardiograms, which are an ultrasound of the heart, used to get a closer look at how the heart and its many parts function.

Living with heart disease

While some forms of heart disease in pets can be serious or fatal, thankfully others can be treated with surgery, medication, or through changes to diet or lifestyle. Your vet can help you to understand the options available to you and to draw up a treatment plan.

As your pet is a part of your family, you obviously want the best for it. Mitcham Pet Hospital can take you through the best options which are specific for your pet, so it can live a happy and long life.

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