Cat Diseases & Illnesses – Heart Disease


Heart disease in cats can be primary, meaning there is no obvious underlying cause, or secondary to another problem. The cat's heart can compensate for a while but heart disease is progressive and eventually the heart cannot adequately compensate and the signs of heart failure will ensue. This is often called congestive heart failure referring to the congestion of fluids that pools in the cat's body when the heart is not pumping efficiently.

Potential underlying causes, symptoms of heart disease in cats and available treatments for cats are discussed below...

  • What are the underlying causes of heart disease in catss
  • Taurine deficiency: Taurine is an essential amino acid for cats and if there is a lack of it in the cat's diet then the heart muscle can be damaged and not expand or contract properly.
  • Hyperthyroidism: An excess of thyroid hormone up regulates the cat's metabolism and increases heart rate. If this goes on for a prolonged period of time then the heart muscle again becomes damaged.
  • Hypertension: This means high blood pressure. This is also usually due to an underlying cause such as hyperthyroidism as mentioned above and also kidney disease. Prolonged high blood pressure can damage the cat's heart and blood vessels and lead to heart disease.

Heart disease can also occur as a result of wear and tear on the heart throughout life and as a result of infections or injury.

Types of heart disease in cats

Hypertrophic Cardiomyopathy (HCM): This is when the cat's heart muscle becomes very thick so it cannot relax or contract properly and there is very little space in the chamber for the blood to fill.

 Restrictive Cardiomyopathy (RCM): In this disease, the cat's heart muscle undergoes fibrosis or scarring which restricts its ability to relax and fill properly with blood.

What are the symptoms of congestive heart failure in cats?

  • Lethargy
  • Inappetance
  • Breathlessness including open mouth breathing

 Cats do not cough as dogs with heart failure do. Dogs primarily have fluid IN the lungs, called pulmonary oedema whereas cats more often develop fluid in the space AROUND the lungs which is called a pleural effusion. This restricts the expansion of the lungs causing the cat to struggle for breath.

Thromboembolic disease: Abnormal blood flow can sometimes activate blood clotting and clots often form in the chambers of the heart. Parts of these clots can break off and circulate in the blood and lodge in smaller blood vessels. The most common place for this to happen is the place where the blood vessels to each back leg and the tail split. This stops blood flow to the back legs and tail causing them to become cold and painful. The clots can sometimes be dissolved with aspirin or heparin but the prognosis is not good as it is an indicator of underlying heart disease.

How is heart disease in cats diagnosed?

The clinical signs as described above are very suggestive of heart disease in a cat. On clinical examination of the cat the vet may also detect a heart murmur, poor pulse quality, pale mucous membranes and abnormal lung sounds. Further tests such as imaging of the cat's heart and lungs are useful and this consists of x-rays and ultrasound. An electrocardiogram or ECG can also be helpful as this measures the electrical conduction of the heart and can detect abnormal heart rhythm. Blood tests may be indicated to assess things like kidney function and thyroid hormone levels and blood pressure measurements may also be important.

How can feline heart failure be treated?


  • Angiotensin Converting Enzymes Inhibitors (ACEI): These drugs suppress the cascade of hormones that make up the compensation mechanism of the heart. This gives the cat's heart a chance to relax and relieves stress on the heart muscle helping to prevent further damage. Your vet may prescribe your cat a drug called Fortekor which falls into this category of drugs. Fortekor 2.5mg is made by Novartis Animal Health and is available in tablet form in packs of either 28 or 56 tablets in blister strips. Fortekor is to be given orally once daily with or without food.
  • Calcium Channel blockers: Calcium channels are involved in muscle contraction and blocking them causes the muscle to relax better so it gives the heart a chance to fill properly with blood before contracting. Hypercard is a calcium channel blocker licensed for use in cats, manufactured by Dechra. Hypercard comes in a pack of 30 tablets in blister packs.
  • Beta Blockers: These help to slow the heart rate which again gives the heart muscle a chance to relax and aids filling.
  • Amlodipine: This drug reduced blood pressure in cats which is often found in cases of heart disease and high blood pressure can further damage organs such as the eyes and kidneys.
  • Aspirin: This can be used in thromboembolic disease as described above. Aspirin can help to dissolve the clots and restore blood flow to the back legs and tail. This should only be given as per veterinary direction, do not give aspirin at home without consulting a vet.
  • Diuretics: These are drugs which cause the body to reabsorb fluids from places that it shouldn’t be such as the lungs and abdomen as described above. The fluid is absorbed into the bloodstream then these drugs act on the kidney which produces more urine to get rid of the fluid. There are different diuretics which act on different parts of the kidney. These include Frusemide or Frusecare, frusemide is the active ingredient. These drugs can be used separately or together and your vet may want to monitor kidney function when using these drugs. Frusemide will normally be given one to two times daily by mouth and you will probably notice that your pet will want to drink more and will urinate more frequently when taking Frusemide.

What should I be feeding my Cat with Heart Disease?

There are prescription diets such as Hills h/d and Royal Canin Cardiac which are specially formulated for animals with heart disease. They are low in salt as high salt levels can cause fluid retention and raise blood pressure. It is also important to use diet to control the weight of animals with heart disease being overweight puts extra strain on the heart and can speed up the deterioration of the disease.

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