Published by: Ingrid King. Last Updated on: February 2, 2023 by Crystal Uys


Buckley was diagnosed with heart disease in February of 2007 and succumbed to the disease in November of 2008, so this is a topic close to my heart.   A check up prior to dental surgery revealed a heart murmur, and a subsequent cardiac ultrasound showed that she had restrictive cardiomyopathy.  As a result, I’ve experienced the challenges of caring for a cat with heart disease firsthand.

Feline heart disease is far more common than most cat owners realize, and it can strike any breed of cat at any age.  What makes feline heart disease very challenging is the fact that cats rarely show the warning signs that are typical for heart disease, such as shortness of breath, exercise intolerance, coughing or weakness) until the disease is quite advanced.


For many cat owners, the first time they even learn that their cat has heart disease is during a regular check up, when their veterinarian may discover a heart murmur.  Not every murmur is an indicator of heart disease, but it definitely requires further diagnostics, such as an ECG, or electrocardiogram, chest x-rays, and a cardiac ultrasound.  These tests will show changes to the size and shape of the heart, whether there is fluid present in the chest, and abnormalities of the heart valves.  A cardiac ultrasound can actually determine the degree of heart disease, not just the presence of it.

There are three types of feline heart disease.

Hypertrophic cardiomyopathy

HCM is the most common form of feline heart disease.   The walls of the heart are thickened, reducing the amount of blood pumped out with each beat. As a result, the heart has to work harder.  These changes in the heart can lead to leakage at the valves and development of a murmur. As the disease progresses, the heart can become so thickened that it cannot pump blood adequately.  This usually results in fluid accumulation in the lungs.  Typically, the age of onset is young adulthood, although it has been diagnosed in cats as young as six months old.  It is most common in middle-aged male cats, but can be seen in either gender.  There appears to be a genetic component as some breeds, especially Maine Coons, Ragdolls, Persians and American Shorthairs, seem to be predisposed to this condition.  HCM is the most treatable form of heart disease.

Dilated cardiomyopathy

DCM presents with an enlarged heart chamber and thinned heart walls, which means that the weakened heart cannot pump efficiently.  This can cause fluid accumulation in the lungs and/or chest (similar to congestive heart failure in humans).  This form of heart disease has become less common, because research a few years ago showed that a deficiency of taurine in feline diets was one of the main causes.  Since then, most commercially manufactured diets for cats have been formulated with taurine.

Restrictive cardiomyopathy

RCM is a less common type of heart disease in cats. It is more difficult to detect, as many cats will have near normal echocardiograms, but their heart walls seem hardened and sometimes even form scar tissue.  As a result, the heart becomes less efficient at pumping blood.  This form of heart disease has a very poor prognosis.


Treatment of feline heart disease depends on the type of disease diagnosed and the severity of the condition.  Therapy is geared toward supporting the strength of heart contraction and reducing fluid build up.  Many of the medications used to treat feline heart disease, such as betablockers, diuretics, calcium channel blockers and vasodilators are the same medications used in the management of human heart disease.  Dietary management may be part of the treatment.

Blood Clots

Blood clots are a potentially deadly complication of heart disease. These clots can form when changes in the shape of the heart walls cause blood to move through the heart in an abnormal flow pattern, leaving stagnant spots were coagulation can occur. The vast majority of these clots lodge at the very end of the aorta, the biggest artery in the body, where it branches off to supply the rear legs and tail. When this happens, the affected cat will be literally fine one second and paralyzed the next. The pain is excruciating. This is a life-threatening crisis with a very poor prognosis for survival. It is a frightening scenario for any cat owner to contemplate.  Medications such as aspirin or Plavix can help thin the blood to prevent clotting, but are not without side effects.

The outlook for a cat suffering from heart disease depends on many factors:  age, form and severity of the disease, other health issues, and more.  As with most diseases, early detection and intervention can be key.

Photo by John Seidman, Flickr Creative Commons

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