Cats can develop heart disease just as humans can — and congestive heart failure is one of these shared conditions. This condition occurs when a cat's heart fails to pump as effectively as it should, resulting in the buildup of fluid in places where fluid should not be — causing signs of congestive heart failure in cats. This misplaced congested fluid leads to a kitty going down hill quickly, often struggling to breathe. While congestive heart failure affects both dogs and cats, cats have their own unique set of diseases that often lead to this condition.
Symptoms of Congestive Heart Failure in Cats
The most common symptom of congestive heart failure in cats is difficulty breathing. The most common reason for these cats to have difficulty breathing is accumulation of fluid in their chest cavity, according to Merck Veterinary Manual. As fluid accumulates in the chest cavity, the lungs are unable to inflate properly. In turn, this causes cats to develop rapid, shallow, and distressed breathing. The lungs themselves may also become congested with fluid, impairing their ability to function properly. Compared to dogs, cats with heart disease also have significantly higher risks for developing blood clots in their legs. This more commonly occurs in the hind legs and may manifest as acute, severe pain or loss of normal limb function. Other signs may include:
- Coughing
- Lethargy
- Weight loss
- Abdominal bloating (due to fluid accumulation)
- Loss of appetite
- Vomiting
- Loss of consciousness
Unlike dogs where valve disease is a common culprit for heart failure, cats usually develop heart failure secondary to damaged heart muscle. In fact, according to the University of Pennsylvania School of Veterinary Medicine one of the most common causes of congestive heart failure in cats is a disease called hypertrophic cardiomyopathy, or HCM. HCM results in thickening and scarring of the heart muscle, preventing the heart chambers from properly filling with blood. This forces the heart to work harder in order to keep pumping the same amount of blood, which exacerbates the injury to the already damaged heart muscle. Although much remains to be learned about how this disease develops, a genetic component has been identified in cats and the two most commonly affected breeds are Maine coon and rag doll cats. A potentially reversible manifestation of this disease can also be seen in cats with thyroid disease (hyperthyroidism). Males do seem to be affected more than females, but no cat is immune from this life-threatening condition.
If you are concerned that your cat is showing signs of congestive heart failure, you should contact a veterinarian immediately as this disease has the ability to become rapidly life-threatening.

Is It Curable?
Unfortunately, most of the damage that occurs in the heart during heart failure is usually irreversible. However, with proper treatment you may be able to temporarily correct fluid buildup in the chest, lungs, or abdomen and start your cat on medications that help slow any further damage to the heart. You'll need to work closely with your veterinarian to determine your cat's prognosis. Common tests your vet may want to run could include blood work, chest X-rays and a heart ultrasound to best identify the root cause of the heart disease. One important exception for irreversible heart disease is that which has occurred secondary to thyroid disease. In these cats, it's possible that by treating the heart failure and underlying thyroid disease you could see long-term resolution of their heart disease. This further emphasizes the importance of working closely with your veterinarian to understand the underlying cause of the heart failure and what treatment options may be available.