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Don’t go breaking my heart – four common diseases of the heart affecting dogs and cats

August 30, 2019

Would you know if your dog or cat had a heart problem? Lets talk about the heart – so small, so important, so clever, so simple! As this is valentines month, we thought it’d be and a good idea to talk about this incredible little organ that keeps us alive every second of every day without us even having to think about it. Many a song has been written about broken hearts and that is what we are going to talk about today!

As well as taking charge of our emotions, our hearts also keeps as alive, pumping fuel and oxygen to all parts of our bodies and removing waste via the blood stream. Because the heart is so vital to life as we know it, the body has plenty of support systems in place to help cope when the heart doesn’t work as well as it should so dogs and cats can cope with a certain amount of heart disease before we have to intervene to help.

When it comes to heart problems there are basically 4 things that can go wrong:

  1. The valves in the heart can be become leaky. This is common in dogs especially smaller breeds like the Cavalier King Charles Spaniel. Leaky valves make a whooshing sound as blood flows through them. We call these sounds ‘murmurs’ and we grade them on a scale of 0 (not audible) to 6 (so loud they can even be felt). Generally the louder the murmur the more leaky the valve and the more likely that help is needed
  2. The heart muscle becomes diseased and weak (cardiomyopathy).This is more common in cats but can also occur in dogs especially larger breeds of dogs like Doberman Pinchers and Irish Wolf Hounds
  3. The electrical ‘wiring’ inside the heart muscle controlling the rate and rhythm of the heart beat can short-circuit causing either an erratic and abnormally fast or abnormally slow heart beat
  4. Fluid can build up around the heart and squash it thus preventing it from pumping properly. This is called ‘pericardial effusion’.

Leaky valves

There are 4 valves in the heart and these open and close making sure that the blood is always flowing forward. Leaky valves occur when the valves are too narrow, don’t open fully or become thickened and distorted. https://youtu.be/TqY_dGxEmy4 The most common result of this type of problem is that fluid starts to build up in the lungs causing symptoms such as lethargy, coughing and heavy breathing https://youtu.be/9bsbXvtsr8k

Heart muscle disease (cardiomyopathy)

These are various forms of heart muscle disease. The most common form is Dilated Cardiomyopathy https://youtu.be/LZivtpGKX-E. The result of these diseases is also usually fluid build up in the lungs with very similar symptoms to leaky valves above. Fluid can also build up in the belly as a result of heart problems.


This usually occurs with other heart problems like leaky valves or heart muscle disease. What happens here is that the electrical circuitry within the heart is damaged and this results in a super fast or incredibly slow heart beat. As a result, the heart cannot deliver important fuel and oxygen to the body and this results in weakness and collapse. Here is a link to a human blog but the same principles apply to dogs and cats https://youtu.be/iAAuHMglbfU

Lastly pericardial effusion

This is a build-up of fluid around the heart. This fluid can compress the heart and stop it working properly. As a result, it struggles to deliver much needed oxygen and fuel to all the organs of the body including the brain. This can result in weakness and sometimes collapse and shortness of breath. A common cause of pericardial effusion is growths in or around the heart but sometimes fluid builds up in this location for reasons we don’t fully understand. https://youtu.be/qAlU8qhC1cU

Most of these conditions are fairly easily diagnosed by a combination of ultrasound, chest x-rays and ECG (electrocardiography). We usually also like to run blood tests at the same time to see if the heart condition has affected any of the other organs in the body to any extent. If you have any concerns at all about our pet having a heart condition, please let us look into it for you because there is a lot help available if needed. Call The Wylie Veterinary centre on 01708 251200