X-rays of an Enlarged Heart in Dogs

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We made a video compilation of  X-rays of an enlarged heart in dogs. These images were sent by our amazing Facebook followers. 

What is an Enlarged Heart in Dogs?

Enlarged heart, or dilated cardiomyopathy, in dogs is a condition when the heart becomes enlarged enough to be unable to properly contract its muscle which results in blood back up in the chambers. When this happens the blood pushes at the walls of the heart chambers and this results in stretching and thinning the walls. This makes the heart unable to pump properly and unable to maintain circulation throughout the body.

All tissues and organs need blood enriched with oxygen to function properly, especially the lungs and the kidneys. This results in a build-up of fluid in the lungs, and as the heart becomes overloaded, heart failure will set in.

What Are the Causes of an Enlarged Canine Heart?

If you’ve ever wondered what could cause an enlarged heart in a dog, it’s likely because of four different reasons. Heart conditions such as canine dilated cardiomyopathy, hypertrophic cardiomyopathy, and endocardiosis can all lead to an enlarged heart. Infections like endocarditis can also cause some of these symptoms.

Another cause of an enlarged heart can occur because of a buildup of excess fluid in the pericardium. This can be due to a number of reasons including infection or cancer.

In most cases, the cause is unknown for a dog having an enlarged heart. It’s important to have a veterinarian examine your pet and conduct tests to attempt to determine what is causing these symptoms.

Dilated cardiomyopathy

Dilated cardiomyopathy is the most common type of heart disease in pets. It affects dog breeds across the board, but is more commonly seen in large and giant dog breeds like the Great Dane, the Saint Bernard, and others. Dilation occurs because of a lack of blood supply to the heart muscle itself. Blood vessels become inflamed and dilate, or enlarge as a result.

Dilated cardiomyopathy can be inherited but it’s also seen in dogs that have acquired the disease after being vaccinated or receiving heartworm meds. A misdiagnosis of cancer can also lead to the disease as well.

Hypertrophic cardiomyopathy

In this condition, the heart muscle becomes abnormally thickened. The thickening occurs because the heart muscle cells do not contract normally and are filled with an abnormal amount of proteins instead.

If these proteins are released into the bloodstream, they can cause other heart problems or other organ damage.


Endocarditis is a condition where the valves in the heart become inflamed and damaged. They also have too much fluid built up on their surface material which affects how they function. This can cause blood to pool in the heart and can lead to dilation of the left ventricle and other complications.


What are the symptoms of an enlarged heart in dogs?

Symptoms of an enlarged heart in dogs may vary and can include some of the following:
– irregular or weakened pulse; muffled or crackling sound while breathing, weakness and lethargy, weight loss and loss of appetite, rapid breathing and shortness of breath, coughing, heart murmurs and arrhythmia, syncope, sudden death.

What is the Treatment of an Enlarged Heart in Dogs?

For treating an enlarged heart it is very important to find the underlying cause and if possible treating the underlying cause in order to treat the heart condition. Dogs that suffer from respiratory distress because of the enlarged heart will need oxygen therapy and fluids in order to correct any fluid imbalances.
Sometimes if there is too much build-up of fluid in the chest cavity it can be drained with a needle.
There are prescription medications that can improve the condition and drain the excess fluid that builds up in the body but these medications help manage the condition, they are not definite treatment.
In the video below you can see the compilation of enlarged heart cases.

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