Congestive Heart Failure in Cats: Causes, Symptoms, & Treatment

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Congestive heart failure (CHF) occurs when the heart is unable to pump enough blood around the body. This results in blood backing up in the vessels, and can cause fluid to build up in the lungs, abdomen, or both. The most common symptom of congestive heart failure in cats is difficulty breathing, due to fluid in the lungs.

Other Names: Heart failure

Common Symptoms: Breathing difficulties, weight loss, fluid from the nose, reluctance to exercise

Requires Ongoing Medication: Yes, lifelong

Vaccine Available: No

Treatment Options: Acute – oxygen, low-dose sedative, diuretics Chronic – diuretics, ACE-inhibitors, pimobendan, blood thinners

Home Treatment: Ensure receives medication and regular check-ups; cardiac diet

In cats, CHF usually occurs due to an underlying heart problem. There may not have been any symptoms until the heart can no longer cope and begins to fail. This can happen suddenly (acute onset) or develop slowly over time (chronic).

Learning your cat is suffering from heart failure is very distressing. However, many cats can be stabilized with treatment. Read on for everything you need to know about CHF in cats, from how it is diagnosed to what you can do at home.

What Causes Heart Failure in Cats?

Heart failure happens because of an underlying heart condition, which is often undiagnosed. Megaflopp / Shutterstock.com

Cats suffering from congestive heart failure have usually had an underlying heart condition for some time – even if you were not aware of it. Most commonly, a condition called hypertrophic cardiomyopathy (HCM), where the heart muscle becomes abnormally thickened.

Because of this, the chambers inside the heart get smaller and cannot fill up with blood making it hard for the heart to pump blood around the body. Cats can compensate for this for some time, meaning they often show no outward symptoms of heart disease until the heart can no longer cope and goes into the first stages of heart failure.

When the heart begins to fail, it stops being able to pump blood effectively around the body. This means fluid begins to accumulate in the lungs, and sometimes the abdomen. The fluid – or congestion – causes the breathing difficulties we often see as the first sign of CHF in cats.

Conditions such as hyperthyroidism or high blood pressure can make a cat more likely to develop HCM – so it is important to treat these conditions effectively. It is also more common in certain breeds, particularly large breeds, such as Maine Coons, Ragdolls, Persians, and British Shorthairs. But in other cases, we do not know why it happens.

Whilst HCM is the number one cause of heart failure in cats, there are several less common causes:

• Other heart conditions, including congenital heart disease
• Heartworm
• Nutrition
• Trauma
• Toxicities
• Heatstroke
• Electrocution
• Infection
• Tumors

Symptoms of Cat Heart Failure

As a veterinarian, the most common symptom I see in cats with CHF is difficulty breathing (due to fluid in and around the lungs). This can be a subtle change, such as noticing that your cat is breathing faster than usual at home. You may notice your cat sitting strangely with the neck stretched outwards and their elbows out—a posture that helps them inhale air more easily.

Sometimes the difficulty breathing may be more obvious and distressing, such as open-mouth breathing, coughing, or gasping. Cats usually only breathe through their noses, so a cat breathing with its mouth open is always a cause for concern.

As well as changes in breathing, symptoms of CHF in cats can include:

• Lethargy or exercise intolerance
• Weight loss
• Loss of appetite
• Cold ears and paws
• Pale gums and eyelids
• Enlarged abdomen (due to fluid in the abdomen)
• Fluid from the nose or mouth
• Collapse
• Sudden death

Your veterinarian may also detect a heart murmur, a fast or irregular heartbeat, or weak pulses on their physical examination.

If you are worried your cat may be suffering from CHF, please seek urgent veterinary help. It is a serious condition, but quick diagnosis and treatment can be life-saving.

Diagnosis of Heart Failure in Cats

The only way to diagnose the underlying heart condition is with an ultrasound – or ‘echo’ – of your cat’s heart. Libre / Shutterstock.com

Many cats with CHF come in with severe and life-threatening breathing difficulties. In these cases, your veterinarian will often suspect CHF just by examining them. This is important as very unwell cats need emergency treatment and may be too critical to undergo tests safely.

But in cats who are stable, or have been stabilized with treatment, there are several tests your veterinarian may recommend:

• Blood tests: Blood tests give information on your cat’s overall condition. They can also diagnose specific conditions such as hyperthyroidism or heartworm, which may be contributing to your cat’s heart disease.
• Electrocardiogram (ECG): An ECG looks for changes in the electrical rhythm of your cat’s heart, which are common in cats with heart failure.
• Echocardiography: An echo is an ultrasound of your cat’s heart which allows diagnosis of the underlying cause of your cat’s heart failure. Your cat may need to be referred to a specialized veterinary cardiologist for this.
• Chest X-Rays: Many of your cat’s symptoms will be caused by fluid build-up in the lungs. This ‘congestion’ can be seen on x-rays of your cat’s chest.

Treatment of Heart Failure in Cats

Congestive heart failure can come on suddenly, requiring emergency treatment in a veterinary hospital. In other cases, it can develop gradually and may be managed with medication at home to slow the progression.

Emergency Treatment of Congestive Heart Failure in Cats

Cats with severe CHF are usually in severe respiratory distress and need immediate emergency treatment to stabilize their condition. They must be handled gently to avoid worsening their condition. So, your veterinarian may not feel it is safe to perform tests or give certain treatments until they are more stable.

The priorities for emergency treatment of CHF in cats are:

• Gentle handling
• Reducing stress – this may include a low-dose sedative injection
• Oxygen therapy
• Reduce fluid build-up with diuretic medication (such as furosemide) or a drainage procedure

Some cats may need an emergency procedure to remove fluid from their chest (thoracocentesis), abdomen (abdominocentesis), or around the heart (pericardial tap), using a needle.

Severe CHF is a life-threatening condition, and treatment is not always successful. If your cat does not respond to the treatment, euthanasia may be the kindest option. However, some cats will show improvement within a few hours of emergency treatment. Even if this is the case, most will need to be hospitalized for 24-48 hours before they are stable enough to go home.

Long-Term Management of Congestive Heart Failure in Cats

Sadly, there is no cure for congestive heart failure. Once your cat is stable, the goal of treatment is to reduce their symptoms and slow the progression of the disease. They may be placed on several medications.

Diuretics (commonly furosemide) are the main treatment for heart failure. They reduce the fluid build-up around the lungs, helping your cat to breathe more easily.

Your veterinarian may recommend other medications, such as angiotensin-converting enzyme (ACE) inhibitors or pimobendan. These drugs work by helping the heart function more effectively or reducing its workload. Blood-thinning medication (such as clopidogrel) may also be prescribed to reduce your cat’s risk of developing a blood clot (feline arterial thromboembolism), a serious complication of heart disease in cats.

How to Care for Your Cat With Heart Failure

Heart failure is a progressive condition so your cat should have regular checks with your vet. Kzenon / Shutterstock.com

Cats who respond to treatment can live for months or years after diagnosis with the right veterinary care. The top three things you can do at home are:

• Successfully give your cat their medication
• Manage their diet carefully
• Attend regular check-ups with your veterinary team

Successfully Medicating a Cat With Heart Failure

As a veterinarian, I can prescribe lots of medications to help your cat’s heart. However, one of the greatest challenges of treating cats with heart failure is compliance – essentially, how successfully you can give your cat their medication. We all know this is easier said than done, and in cats with heart conditions, it is even more important not to stress them out. Read How to Give Your Cat a Pill for tips on giving your cat tablets.

However, it is important to be realistic. I find the more medications a cat is prescribed, the harder they tend to be to administer. So if you’re finding medicating your cat stressful, you should prioritize the medications that benefit your cat the most after a discussion with your veterinary team. This is usually a diuretic.

Choosing the Right Food for Your Cat With Heart Failure

Nutritionists recommend moderate to low-sodium (salt) diets to avoid worsening fluid retention in cats with CHF. High-calorie and high-protein food can help your cat to maintain their weight. There is also some evidence that omega-3 fatty acids can be beneficial for cats with heart problems.

There are many specialized cardiac diets available commercially that can help you meet these requirements easily. But the most important thing is that your cat eats a complete, nutritionally balanced diet. Just be sure to keep an eye on treats, as these can be high in salt.

There is some evidence that grain-free diets are linked to heart problems in cats, so it is safest to avoid these.

Attend Regular Check-Ups

Heart failure is a progressive condition, so what works for your cat one month may be different from the next. Regular check-ups with your veterinary team will allow them to tailor your cat’s treatment for the stage they are at and pick up subtle changes.

Can Heart Failure in Cats Be Cured?

Heart failure cannot be cured. Sadly, in most cases the damage to the heart is irreversible. So, the goal of treatment is to manage the symptoms enough to give a good quality of life – and to slow the progression of the disease as much as possible.

Cats who respond well to initial treatment – either because they are in early-stage heart failure or have an untreated heart condition – have the best prognosis. With good management, many of these cats can live a good quality of life for months to years after diagnosis.

When cats reach end-stage heart failure, especially if they have been receiving treatment for some time, there is usually little that can be done to help. Your veterinary team is there to support you in knowing when it is the right time to say goodbye.

How To Prevent Heart Failure in Cats

The best way to prevent heart failure is to pick up on heart conditions early. Wanwajee Weeraphukdee / Shutterstock.com

Heart failure most often occurs in cats due to an undiagnosed heart condition. By this point, the heart is already damaged and struggling to work properly – leading it to fail. But it can be hard to detect these heart conditions early.

Many cats with heart conditions are asymptomatic, meaning you may not have noticed any changes at home. So, regular health checks with your veterinarian are essential to detect a problem before it becomes serious. Early signs of a heart condition include a heart murmur, or an unusual heart rate or rhythm. If your cat has any of these symptoms, they should have an echocardiogram to diagnose the underlying problem.

Regular check-ups, including blood screens and blood pressure monitoring, can also pick up conditions that can lead to heart problems, such as hyperthyroidism.

Other heart conditions (such as dilated cardiomyopathy) have been linked to certain types of diet, including grain-free diets or those lacking taurine. So, make sure you choose a balanced and complete diet for your cat.