Heart Disease in Cats: A Complete Guide to Understanding Feline Heart Health

Cat heart disease is less common than dog heart disease, but when it occurs, it specifically  affects the heart muscle only. The most common type is hypertrophic cardiomyopathy (HCM), which causes the heart walls to thicken. HCM affects about 1 in 7 cats^1-3 and becomes more common with age, affecting up to 29% of senior cats,^2,4 even without other health issues. Read on to learn more about heart disease in cats, what causes heart disease in cats, and how to prevent heart disease in cats.

What Is Heart Disease in Cats?

Heart disease in cats affects how the heart functions. While it most frequently affects the heart muscle, other complications like abnormal electrical impulses (also known as abnormal heart rhythms) can occur and may even cause issues with the sac around the heart.

As heart disease progresses, it can lead to serious, life-threatening complications, like dangerous blood clots that may block blood flow to the legs (arterial thromboembolism or ATE) and fluid building up in the chest and lungs that makes it hard to breathe (congestive heart failure or CHF). You may come across the term “congestive heart disease,” but veterinarians actually use the term “congestive heart failure” to describe the advanced stage of heart disease. These conditions require immediate veterinary attention.  

Symptoms of Heart Disease in Cats: Recognizing the Early Signs¹  

Cats often hide signs of illness, so signs of heart disease in cats can go unnoticed in the early stages. One of the most common signs is low energy and loss of appetite or weight. Unlike dogs, coughing is not a typical sign of heart disease in cats.

Signs or symptoms include:

• Low energy or hiding
• Loss of appetite or weight
• Cold paws or weakness

As the disease progresses and becomes more severe, cats may develop:

• A swollen belly from fluid buildup in the lungs
• Rapid or labored breathing
• Sudden collapse or fainting
• Back leg paralysis from a blood clot

When to See a Veterinarian

Contact your veterinarian right away if your cat shows any of the following:

• Rapid or labored breathing
• Open-mouth breathing or panting when not anxious or hot, and not typical for your cat
• Sudden weakness or collapse
• Inability to use the back legs or dragging one or both legs
• Signs of pain, especially in the back or hind limbs
• Severe lethargy or unresponsiveness

These may be signs of heart failure or another serious or life-threatening heart condition, and immediate care can be critical. If you are ever in doubt, it is always better to be safe and call your veterinary team.

Can Cats Have Heart Attacks?

Is a cat heart attack something you need to worry about? Sudden death in cats is rare but can happen with serious cat heart problems like HCM. It is usually caused by a fatal heart rhythm or a blood clot, not a heart attack. True heart attacks are extremely rare in cats.¹

What Causes Heart Disease in Cats?

In many cats, the exact cause of heart disease is not always known. Factors such as genetics, breed, age, nutrition, and environment can play a role in the development of heart disease in your cat. Stressful situations can put added strain on the heart.5

In addition, while it typically affects the lungs in cats, indoor and outdoor cats are both at risk for developing heartworm disease. This parasite is spread by mosquitoes and can affect the lungs, even with just a few worms. Using year-round heartworm disease prevention is an important step in supporting your cat’s health.⁶

How Heart Disease in Cats Is Diagnosed^1,5,7

Diagnosing heart disease in cats can be challenging, especially because many cats show no obvious signs in the early stages. Veterinarians use a combination of exams, blood tests, imaging, and specialized tools to detect heart problems as early as possible.

Stages of Heart Disease in Cats^1,4

Heart disease in cats can progress over time. Veterinarians use stages of heart disease in cats to describe how advanced the condition is and to help guide treatment and monitoring.

• Stage A: At-risk cats with no heart changes
• Stage B: Heart changes are present, but without symptoms
  • B1: Low risk of heart failure or clots
  • B2: Higher risk of heart failure or clots
• Stage C: Signs like labored breathing or blood clots have developed
• Stage D: Symptoms are more severe and harder to manage despite treatment

Treatment of Cat Heart Disease

Cat heart disease treatment depends on the type and stage of the condition. Your veterinarian may recommend medications or advise dietary alterations. Some cats, especially those in early stages, may not need medication. In these cases, your veterinarian may recommend regular checkups and monitoring to track any changes.

How Long Can Cats Live With Heart Disease?¹

Life expectancy depends on the type and stage of heart disease. Cats in early stages often live for years with regular monitoring. In more advanced stages, the outlook is more guarded, and many cats may live months rather than years depending on the severity of the disease and response to treatment. Some conditions, like heart disease caused by taurine deficiency or hyperthyroidism, may improve with proper treatment. Cats diagnosed with ATE often have a serious outlook. On average, survival time ranges from 4–8 months. If the cat also has congestive heart failure, survival may be shorter.⁷

While every cat is different, how long cats can live with heart disease often depends on early diagnosis and ongoing care, which can help improve both quality of life and longevity. Talk to your veterinarian to better understand your cat’s condition, expected disease progression, and prognosis.

Heart Health for Cats: Prevention and Proactive Care

Supporting your cat’s heart health starts with regular veterinary checkups, especially for senior or at-risk breeds. Prevention of heartworm disease in cats is also essential, even for indoor cats, even though the parasite doesn't directly affect their heart. At home, monitoring your cat’s sleeping respiratory rate (how many breaths they take while resting) can help detect early signs of heart failure. More than 30 breaths per minute while sleeping may be a concern.  

Feeding a heart-healthy diet with nutrients like taurine and omega-3 fatty acids, reducing household stress, and watching for changes like rapid breathing or appetite loss are also important steps.

Talk to your veterinarian about your cat’s individual needs.

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For more expert tips on cat health, explore our other cat symptom articles.

References

1. Kittleson MD, Côté E. The Feline Cardiomyopathies: 1. General concepts. J Feline Med Surg. 2021;23(11):1009–1027.

2. Payne JR, Brodbelt DC, Fuentes VL. Cardiomyopathy prevalence in 780 apparently healthy cats in rehoming centres (the CatScan study). J Vet Cardiol. 2015;17:S244–S257.

3. Paige CF, Abbott JA, Elvinger F, Pyle RL. Prevalence of cardiomyopathy in apparently healthy cats. JAVMA. 2009;234(11):1398–1403.

4. Fuentes VL, Abbott J, Chetboul V, et al. ACVIM consensus statement guidelines for the classification, diagnosis, and management of cardiomyopathies in cats. J Vet Intern Med. 2020;34(3):1062–1077.

5. Kittleson MD, Côté E. The feline cardiomyopathies: 2. Hypertrophic cardiomyopathy. J Feline Med Surg. 2021;23(11):1028–1051.

6. Nelson CT, McCall JW, Moorhead A, et al. American Heartworm Society Feline guidelines for the prevention, diagnosis, and management of heartworm (Dirofilaria immitis) infection in cats. 2024. 

7. Tilley LP, Smith FWK, Sleeper MM, Kraus MS. Manual of Canine and Feline Cardiology [e-book]. 6th ed. Elsevier; 2025.