Cats are famously good at hiding illness, and heart disease is one of the best examples. A cat can have significant heart changes while still eating, sleeping and greeting you at the door as usual. Understanding why helps owners take routine checkups seriously and recognize the signs that need urgent attention.
The most common culprit
Hypertrophic cardiomyopathy, often shortened to HCM, is the most commonly diagnosed heart disease in cats. In HCM, the walls of the heart, especially the left ventricle, become thickened. That makes it harder for the heart to relax and fill properly. It can occur in cats of any breed or mix, and some breeds are known to be predisposed. Heart muscle changes can also occur alongside other conditions, such as an overactive thyroid or high blood pressure, which your veterinarian may check for.
Why it goes unnoticed
Unlike dogs, cats with heart disease often do not cough. They also tend to limit their own activity, so reduced stamina may not be noticed in an indoor cat who naps much of the day. A murmur or irregular rhythm found during a routine exam is sometimes the first clue, though not every cat with heart disease has a murmur, and not every murmur means disease.
When a veterinarian suspects heart disease, they may recommend tests such as chest X-rays, blood tests or an echocardiogram, which is an ultrasound of the heart.
Signs to watch for
- Breathing changes. Faster or more effortful breathing at rest, or breathing with the mouth open. Cats rarely pant, so open-mouth breathing in a calm cat is a concern.
- Hiding or lethargy. Withdrawal from usual activities or favorite spots.
- Reduced appetite. Eating less or losing weight.
- Sudden hind-leg weakness or pain. Some cats with heart disease can develop a blood clot that blocks blood flow to the back legs. A cat may suddenly cry out, be unable to use its hind legs, or have cold back paws.
When it is an emergency
Seek veterinary care immediately if your cat is breathing with effort or with an open mouth, has blue or gray gums, collapses, or suddenly cannot use one or more legs. These signs can be life-threatening. Call ahead to the clinic or emergency hospital if you can, and keep your cat as calm as possible on the way.
What owners can do
- Keep up with routine wellness visits so your vet can listen to the heart regularly.
- Learn your cat’s normal resting breathing rate. Your vet can explain how to count and what is normal.
- If your cat is of a breed known for heart disease, ask whether screening is recommended.
- Mention any changes in energy, appetite or breathing, even if they seem minor.
- If your cat is diagnosed, follow the treatment and recheck schedule your veterinarian sets.
Many cats with heart disease can be managed for long periods. Early detection gives you and your veterinarian more options. This article provides general information only; talk to your veterinarian about your cat’s heart health.
