6 signs your cat may have heart disease

From knowing what to look out for to how it’s treated, our guide to understanding heart disease in your senior cat.

Heart disease is more common among senior cats, but knowing what to look out for means you can help your cat as much as possible. Key signs to look out for include:

• Rapid breathing while resting or increased effort when breathing.
• Reduced activity levels or reluctance to exercise.
• Lethargy and increased sleeping.
• Weight loss or loss of muscle condition.
• Reduced appetite.
• Weakness, collapse or fainting episodes.
• Sudden paralysis or weakness in the back legs, which can be caused by a blood clot.
• Behavioural changes, such as hiding more than usual or appearing withdrawn.

If your senior cat is showing any or all of these signs, it’s time to make an appointment with your vet.

If your cat is having difficulty breathing and is breathing with their mouth open (like a dog panting), this is an emergency and requires immediate assessment by a vet.

Common types of heart disease

Heart disease is fairly common in cats, particularly as they get older. Some forms are present from birth, but the majority develop later in life. The most common group of heart conditions in cats are known as cardiomyopathies, which affect the heart muscle itself.

• Hypertrophic Cardiomyopathy (HCM) is the most frequently diagnosed cat heart disease. It causes the muscular walls of the heart to become abnormally thick, making it harder for the heart to fill and pump blood efficiently. Some cats show no signs for years, while others may develop breathing difficulties, lethargy, heart failure, or blood clots.
• Restrictive Cardiomyopathy (RCM) occurs when scar tissue develops within the heart muscle, making it stiff and less able to relax between beats. This reduces the heart's ability to fill properly with blood and can lead to fluid build-up, heart failure, and an increased risk of blood clots.
• Secondary Heart Disease refers to heart changes that develop as a result of another underlying condition. Common causes include hyperthyroidism and high blood pressure (hypertension), both of which are more common in senior cats. Treating the underlying condition may help manage or slow the progression of the associated heart disease.

Medical care for older cats

If a vet suspects heart disease, they will usually begin with a physical examination, including listening to the heart and lungs. They may detect a heart murmur, abnormal rhythm, or other changes that warrant further investigation. However, some cats with heart disease can have a normal examination, so additional diagnostic tests are often needed.

Common diagnostic tests include:

• Chest X-rays (radiographs) to assess heart size and check for fluid in or around the lungs.
• Echocardiography (heart ultrasound), which is considered the gold standard for diagnosing the type and severity of heart disease.
• Electrocardiogram (ECG) to identify abnormal heart rhythms.
• Blood pressure measurement, particularly in older cats.
• Blood tests, including cardiac biomarkers such as NT-proBNP, and screening for conditions such as hyperthyroidism.

Treatment depends on the type of heart disease and the symptoms present. While many heart conditions cannot be cured, medication can help improve quality of life and control complications.

Examples of medications include:

• Diuretics to remove excess fluid in cats with congestive heart failure.
• Blood-thinning or anti-clotting medications to reduce the risk of dangerous blood clots.
• Medications that help the heart relax and work more efficiently, which may be recommended for certain forms of cardiomyopathy.
• Treatment of underlying diseases, such as hyperthyroidism or hypertension, when these are contributing to the heart condition.

Regular monitoring is often needed, with follow-up examinations, blood tests and repeat scans helping your vet tailor treatment as your cat's condition changes over time. Book a check up with your local vet