Published by: Ingrid King. Last Updated on: October 31, 2022 by Crystal Uys


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

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, making the heart work harder. These changes in the heart can lead to leakage at the valves and cause development of a murmur. As the disease progresses, the heart can become so thickened that it cannot pump blood adequately, which usually results in fluid accumulation in the lungs. HCM typically starts in 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 in the late 1980’s identified a deficiency of taurine in feline diets as one of the main causes. Since then, most commercially manufactured diets for cats have been formulated with sufficient taurine levels.

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.

Diagnosis of feline heart disease

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.

Treatment of feline heart disease

Treatment will depend on the type of disease and the severity of the condition. Therapy is aimed at supporting the strength of heart contractions 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.

Blood clots

Blood clots, also known as aortic thromboembolism or saddle thrombus, 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. Medications such as aspirin or Plavix can help thin the blood to prevent clotting, but are not without side effects.

Feline heartworm disease

While more common in dogs, heartworm disease can affect cats as well. Caused by a parasite carried by mosquitoes, cats become infected when the mosquito bites  cat and deposits heartworm larvae into the cat’s bloodstream. Even though cats typically have fewer and smaller worms than dogs with a shorter lifespan,hearworm disease is considered a more serious threat in cats and can lead to significant pulmonary damage and even sudden death. For more information, read Feline Heart Worm Disease.

New blood test can identify heart disease earlier

The proBNT blood test, which has been used in human medicine for years, is now available for cats. This test can help diagnose heart disease earlier, and even identify cats who might be prone to heart disease.

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9 Comments on Feline Heart Disease: What You Need to Know

  1. My cat JJ who ironically looks like the flame point siamese in this picture, was diagnosed in June. He is on 3 different medications and is doing great. I didn’t know he was sick until he got really bad. So almost lost him. He is my baby (14) His sister and brother are 17. So it was so hard for me. I am thankful for every day with him.

  2. I lost my best friend to HCM, 3 years ago. No way was I going to subject him to needle aspirations every couple weeks and meds weren’t working, so I had no choice but to hold him and love him across the bridge. I miss him every day.

  3. I’m interest in cat anxiety, fearful behavoiur what is the cause on a healthy cat after 7 years, I don’t want to put him on prozac.

  4. My stomach feels sick just reading this; so many memories. Such important information that needs to be known.

  5. Things must have really changed over the years for cats with heart disease. I lost one of my cats (the one that I was the closest to) 4 years ago to heart disease and the vet told me there wasn’t much that could be done for cats because they weren’t able to take regular medications as they caused other problems. she didn’t show any signs of being sick until she developed a bad cough which was caused by the fluid buildup around her heart. I was told the only thing they could do was remove the fluld from around her heart (which they did with a needle). I couldn’t put her through that again and we had to make the hard decision of putting her to sleep. My heart is still broke from losing her.

    • So sorry. My cat was diagnosed in June. He has to take 3 different medications but seems to be doing ok. I have to count his breaths at night too. I didn’t know his condition until he got really sick. He is 14, so praying I have a couple more years.

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