Congestive Heart Failure in Cats: Signs, Emergency Care and Outlook

By Tailwisp Editorial TeamUpdated October 20, 20264 min read

The heart is a pump, and when it cannot keep up, the body pays a price. In cats, the first outward sign of heart disease is often a crisis: a cat that suddenly breathes fast with its mouth open. Learning to recognize early signs, and how to measure breathing at home, can give you precious time.

What is congestive heart failure?

In congestive heart failure, a diseased heart cannot pump blood efficiently. Pressure builds up, and fluid leaks into the lungs, called pulmonary edema, or into the chest around the lungs, called pleural effusion. This makes breathing hard. The heart may also be so affected that blood clots form, with serious consequences.

Causes

• Cardiomyopathy. The most common cause is disease of the heart muscle, especially hypertrophic cardiomyopathy, in which the walls thicken. See hypertrophic cardiomyopathy in cats. Other forms include restrictive and dilated cardiomyopathy.
• Hyperthyroidism, which strains the heart. See hyperthyroidism in cats.
• High blood pressure, often linked to kidney disease.
• Congenital defects.
• Heartworm. See heartworm in cats.
• Taurine deficiency, now rare because commercial foods contain it. See taurine: why cats need it.
• Tumors, and other chest disease.

Some breeds, such as Maine Coons and Ragdolls, have inherited risk of heart disease. See maine coon breed profile and ragdoll breed profile.

Signs

Signs of heart failure may be sudden:

• Rapid breathing, over 40 breaths per minute at rest.
• Labored breathing, with the abdomen working hard.
• Open-mouth breathing or panting. See cat panting and open-mouth breathing.
• Blue or pale gums.
• Lethargy, hiding and loss of appetite.
• Cough, less common than in dogs.
• Sudden hind-leg weakness or paralysis, due to a blood clot, which is extremely painful and an emergency.
• Collapse.

Count the breathing rate

A resting respiratory rate is a useful home test. When your cat is asleep or very relaxed, count how many times the chest rises in 30 seconds, and double it. Normal is typically under 30 breaths a minute. Persistently over 40 is a reason to call the vet. If your cat has been diagnosed with heart disease, check once or twice a week, and write the numbers down. See how to check your cat's vital signs.

Emergency care

A cat in respiratory distress is an emergency. Keep it calm, avoid restraint and stress, and go to the vet immediately. Cats in distress can die from stress alone, so minimize handling. Vets provide oxygen, often by a cage or mask, give diuretics to remove fluid, and may drain fluid from the chest. Once stable, they perform tests.

Diagnosis

Chest X-rays show fluid and heart size, and an echocardiogram, an ultrasound of the heart, shows the cause. Blood tests, blood pressure and a thyroid test help to find other contributors. A cardiology specialist may help.

Long-term treatment

• Diuretics, such as furosemide, to control fluid.
• Heart medications, such as pimobendan in some cases, ACE inhibitors, or others, depending on the type of heart disease.
• Blood clot prevention, with drugs such as clopidogrel.
• Treating contributing conditions, such as thyroid disease and high blood pressure.
• Rechecks, with bloodwork, because diuretics affect the kidneys.
• Low-stress home care.

Give medications exactly as prescribed. See how to give a cat a pill.

Outlook

Prognosis depends on the cause and how well the cat responds. Some cats live months, and some years, after diagnosis. Quality of life is the focus. Talk to your vet about monitoring, and when to consider end-of-life care. See cat quality of life and saying goodbye.

Screening

Breeds at risk may benefit from heart screening. Ask your vet about an echocardiogram if you have a predisposed cat, or a murmur is detected. See cat wellness exam: what to expect.

Blood clots and sudden hind-leg weakness

Cats with heart disease can form clots in an enlarged heart chamber. If a clot lodges in the arteries to the back legs, it causes sudden pain, crying out and weakness or paralysis of the rear legs, cold paws and pale or blue pads. This is called an aortic thromboembolism, or saddle thrombus, and is an emergency. Take your cat to a vet immediately. Treatment includes pain relief and supportive care, and the outlook is guarded, but some cats recover use of their legs.

Home monitoring routine

Keep a log of resting breathing rate, appetite, energy, weight, litter box habits and medication times. Pick the same time each day, when your cat is asleep or resting. Show the log at rechecks. If the rate rises or your cat seems less active, call the vet early. Gentle monitoring can catch a relapse before an emergency.

Reducing stress at home

Stress can trigger a crisis in a cat with heart disease. Keep routines steady, provide quiet resting places, avoid unnecessary travel and handle gently. Use food and a calm voice when giving medication. If your cat is hard to medicate, ask about liquid or flavored forms, or transdermal gels.

Diet

Your vet may recommend a diet with moderate sodium, and good quality protein. Avoid salty treats. Keep your cat at a healthy weight. See how to help an overweight cat lose weight.

When to see a vet

See a vet immediately if your cat breathes fast, with an open mouth, or collapses. Use the US vet directory to find a clinic.

This article is general educational information, not veterinary advice. Every cat is different. If your cat is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.