Congestive Heart Failure in Cats

Is your cat struggling to breathe? They may be suffering from congestive heart failure.  

If your cat’s heart can’t pump blood out to the rest of the body efficiently, they may start to accumulate fluid in their lungs.  

This can make it difficult for them to get adequate oxygen and put them at risk for a stroke. 

What Is Congestive Heart Failure in Cats?

Congestive heart failure in cats is a progressive condition in which the heart muscle is too weak to meet the body’s demands. 

To understand heart failure in cats, it’s important to know how the heart muscle works and what it does for your cat's body. 

The heart pumps blood to various parts of the body such as the lungs, brain, kidneys, and limbs. 

The blood provides oxygen and other nutrients to body tissues. Blood circulation also helps to release waste from tissues by removing carbon dioxide. 

When the heart is not functioning properly, it can affect every organ and muscle in the body. 

When heart failure in cats occurs, a feline’s heart has difficulty bringing enough oxygen to tissue and is slow in removing waste. 

This results in fluid congestion as the blood is failing to be pumped out of the heart efficiently. Fluid then backs up and accumulates in the lungs or body. 

When congestive heart failure is not treated, heart function declines. This results in decreased oxygen to the body that’s necessary for life.  

Cats can experience cardiogenic shock where their blood pressure drops; their pulse becomes weak and they experience life-threatening hypoxia (low oxygen). 

If left untreated, congestive heart failure in cats can be fatal. 

Symptoms of Congestive Heart Failure in Cats

Heart failure in cats usually starts as a progression of heart disease, with few symptoms to even suggest your cat is sick. Cats can play, eat normally, and have normal bowel movements early in heart disease. 

As heart disease advances, pet parents may start to notice symptoms. The most common include: 

• Difficulty breathing or panting 

• Lethargy 

• Lack of appetite 

• Coughing 

If your cat is experiencing any symptoms of heart disease or failure, take them to a veterinarian immediately. 

If your cat appears to be healthy, a full physical exam is recommended annually with your veterinarian to detect early signs. 

Early Signs of Congestive Heart Failure in Cats 

Heart disease often has very few signs early on. It’s best if you can catch underlying heart disease before your cat goes into congestive heart failure. 

The best way to catch heart disease early is to have your vet listen to your cat's heart with a stethoscope every year to ensure they have developed no new murmurs (abnormal heart sound) or arrhythmias (abnormal heart rhythm). 

Your cat can be screened early for any stretch or wear on the heart muscle with a blood test called a cardiopet proBNP. This test measures a protein that is released when the heart muscle is stressed and can be helpful in catching heart disease early. 

Watch your cat for any signs of exercise intolerance. If athletic things that used to be easy seem to wear your cat out, it could be a sign of early heart disease. 

It is also helpful to have an idea of what their resting respiratory rate runs. To get this number, count the number of times your cat’s chest rises when they’re awake and calm.  

This number should be under 30. If it’s creeping up, this may indicate early congestive heart failure. 

Signs of End-Stage Heart Failure in Cats 

Signs of end-stage heart failure are usually much less subtle.  

Affected cats are struggling to get oxygen in their bodies. They will likely look like they’re working hard to breathe. They may breathe rapidly or even experience open-mouth breathing. 

Your cat's gums may look less pink and appear more blue or purple-tinged if they are in end-stage heart failure. 

Most affected cats have very little energy and are reluctant to move around. They may not lay down or cozy up in their beds like they used to. Lying on their side leads to pooling of fluid on one side of their lungs and makes it even harder to breathe. 

Occasionally, affected cats will cough. This is much more common in dogs with congestive heart failure than in cats with congested heart failure. 

What Causes Heart Failure in Cats?

Congestive heart disease in cats can be caused by: 

• Birth defects, like patent ductus arteriosus (PDA) or septal defects inside the heart

• Underlying heart disease, like hypertrophic cardiomyopathy (HCM) or dilated cardiomyopathy (DCM) 

• Infections, like endocarditis 

• Other underlying medical conditions, like untreated hyperthyroidism or hypertension 

• Changes in the anatomy of the heart that sometimes come with aging 

• Genetics, with some cat breeds—like Maine Coons, Persians, and Ragdolls—at a higher risk

How Veterinarians Diagnose Congestive Heart Failure in Cats

To diagnose congestive heart failure in cats, a physical exam by your veterinarian may be the only way to tell that something’s wrong. 

Your vet may notice that your cat's heart sounds abnormal when listening with a stethoscope. 

The cat may have a heart murmur, which lets the veterinarian know that there’s blood moving through the heart in an abnormal direction. 

Blood should flow into the heart via just one entrance and out through one exit. 

If blood is allowed to move back in the opposite direction, it will cause a distinctive swishing sound. 

During a physical exam, your veterinarian may also determine if your cat’s heart is beating too fast, too slowly, or with an irregular rhythm (cardiac arrhythmia).   

To diagnose a problem with the heart, your veterinarian will likely want to do several tests including: 

• Blood work. This will test the function of most of the organs, including the thyroid and kidneys. 

• Chest radiographs (X-rays). X-rays will let the vet check the heart size and the condition of the lungs. This is important, since the lungs and heart work closely together. 

• Blood pressure. This is to make sure your cat does not need to be treated for hypertension. Hypertension can come from heart disease, but it can also contribute to heart disease. 

• An ultrasound of the heart. This is called an echocardiogram, which allows the vet to see what may be causing an abnormal sound and measures how the heart is working. 

None of the tests are invasive or painful, although some anxious cats may be more comfortable with sedation. 

Some cats with severe symptoms may require supplemental oxygen during testing. 

Some of these tests can be easily done with your local veterinarian, while others may need a veterinary cardiologist to fully diagnose the problem. 

Congestive Heart Failure in Cats Treatment

Once congestive heart failure in cats has been diagnosed, medications (like furosemide) may be used to help the heart function better, normalize the rhythm, or reduce blood pressure.  

Most of these medications can increase quality and quantity of life.  

Diuretics, also called “water pills”, are an important part of congestive heart failure treatment.  

These medications work to help pull fluid off the lungs so that your cat can breathe easier. The most prescribed diuretics in cats are furosemide and spironolactone. 

Affected cats will often be prescribed an ace-inhibitor. This type of medication helps the vessels relax and widen so it’s easier for the heart to pump blood out to the body.  

Enalapril and benazepril are common examples of these medications used in cats. 

Cats that have heart disease are at an increased risk of having a stroke.  

Because of this, many cats with congestive heart failure will also be prescribed medication, like clopidogrel, to reduce their stroke risk. 

If your cat also has hypertension, they may be prescribed a blood pressure medication, like amlodipine. 

Your cat’s cardiologist may prescribe additional medications depending on what they appreciate on your cat’s EKG and echocardiogram. 

With regular medication, you can help your cat breathe easier and live a more comfortable life after a diagnosis of congestive heart failure. 

Monitoring Cats With Congestive Heart Failure

Medications are used to control quality of life in cases of congestive heart failure in cats. They are usually effective with proper patient monitoring. 

Your veterinarian will likely want to perform blood work frequently when medications are first started to ensure your cat has the proper dose.  

This will also help the vet know how well your cat is tolerating the medications.  

Watch for any changes in behaviors or eating habits. Share any side effects that you notice at home with your vet. 

Watch for any decreased appetite, weight loss or poor energy. Let your vet know right away if your cat’s getting worse instead of better. 

Your vet may teach you how to monitor the respiratory rate at home and may ask for frequent checkups so they can listen to your cat’s heart. 

A veterinary diet, like Hills Multiorgan Complex Support, may be recommended so that your cat is eating what is best for this condition. 

Once the heart failure is under control, a cat will likely need to be on medication for the rest of their life, with annual monitoring by their vet. 

If your cat has other medical conditions such as kidney disease, hypertension, or pulmonary disease, it can make treating the heart failure more complicated.

Prognosis of Congestive Heart Failure in Cats 

Many pets can recover from congestive heart failure in cats, but they must be in treatment for life. 

The prognosis for congestive heart failure is guarded in cats. While some cats can live several years after a diagnosis, the average life expectancy for affected cats is six to 12 months.