Heart problems in cats include cardiomyopathies, endomyocarditis, bacterial endocarditis, endocardial fibroelastosis, myocarditis, pericardial disease, arrhythmias, and heartworms.
Cardiomyopathy in Cats
There are three basic cardiomyopathies: dilated, restrictive, and hypertrophic.
Dilated Cardiomyopathy (DCM), a disease in which the heart muscle becomes stretched, is most often caused by a diet with insufficient taurine (an animo acid cats require), though toxins, infections, or other problems can also trigger it. DCM is quite rare in countries where cat foods are routinely supplemented with taurine.
With restrictive cardiomyopathy (RCM), an inflammatory process of unknown origin renders the heart muscle unable to expand. RCM may be triggered by stress, endocarditis, lymphoma, or other disease.
Hypertrophic cardiomyopathy (HCM), a thickening of the heart muscle that makes it difficult for the heart to pump blood effectively, is the most common type of heart disease in cats. The condition is hereditary, with certain breeds (such as the American Shorthair, Persian, Maine Coon, Ragdoll, and Siamese) being particularly vulnerable. HCM may also be triggered by conditions such as acromegaly (a disease that causes too much growth hormone to be released into a cat’s system) and infiltrative myocardial disease (i.e., lymphoma), both of which are relatively rare in cats.
HCM can strike cats at any age, though it’s most common among young to middle-aged cats. Hypertension and hyperthyroidism may exacerbate it.
Symptoms of feline hypertrophic cardiomyopathy include:
- Appetite loss/weight loss
- Breathing difficulties/rapid breathing
- Coughing (less common in cats than dogs)
- Lethargy
- Weakness
- Paralysis of one or both of the hind legs due to thromboembolism (a travelling blood clot that lodges in a narrow artery)
Some cats with cardiomyopathy never develop observable symptoms.
Cardiomyopathy renders a cat unable to cope with stress, which increases the risk of death as a result of high temperatures, conflicts with other animals, veterinary procedures, moving house, and car travel. Treatments may include reducing stress and switching to a low-salt diet. If the disease is being triggered by hyperthyroidism, treating the underlying thyroid disease will have a beneficial effect.
There are medications to treat cardiomyopathy, but treatment doesn’t always bring improvement. Cats with no symptoms usually have a good prognosis, whereas cats with heart failure survive an average of 3 months (though approximately 20% do live for 3 years or more after the diagnosis). If the legs have been paralyzed due to clots, the prognosis is poor, and in most cases the cat must be euthanized.
Feline Endomyocarditis
Endomyocarditis, an inflammatory heart disease, is far less common than HCM. Male cats aged 1-4 years are most vulnerable to the disease, which typically develops after a stressful event (such as surgical anaesthesia, relocation, bathing, or vaccination), and is accompanied by interstitial pneumonia, a severe and life-threatening illness. The primary symptom is shortness of breath beginning approximately 5-21 days after a stressful event.
There is no standardized treatment for Endomyocarditis. Supportive ventilation and oxygen therapy may be provided, but prognosis is often poor, though some cats beat the odds and survive. The cause of this disease is unknown.
Bacterial Endocarditis in Cats
Bacterial endocarditis may be caused by a variety of infections, including uterine, dental, skin, post-surgical, and pneumonia. Symptoms may include:
- Appetite loss/weight loss
- Lethargy
- Fever
- Vomiting
- Muscle stiffness
- Weakness
- Paralysis due to thromboembolism
Treatments include the administration of antibiotics to cure the infection and ongoing therapy for any heart problems caused by it.
Feline Endocardial Fibroelastosis
This rare inherited heart disease causes severe thickening of the heart muscle, eventually leading to heart failure. Siamese and Burmese cats are those most likely to be afflicted, with problems typically arising when kittens are under 6 months old. Symptoms include:
- Heartbeat irregularities
- Breathing difficulties/noisy breathing
- Paralysis
Treatment may include medication, oxygen therapy, and lung membrane tap. Sadly, recovery is unlikely, though the cat may gain a little extra time with treatment.
Myocarditis in Cats
Myocarditis is an inflammation of the heart that may be caused by bacterial infection, toxoplasmosis, potassium disturbances, cardiomyopathy, hyperthyroidism, chronic renal failure (CRF), medications, toxins, lymphosarcoma, or taurine deficiency. Symptoms include:
- Fever
- Lethargy
- Weakness
- Coughing
- Breathing difficulties
Treatment requires addressing the underlying trigger as well as any resulting heart problems.
Pericardial Disease in Cats
This uncommon type of heart disease involves the pericardium, a thin sac surrounding the heart. Causes may include cardiomyopathy, feline infectious peritonitis (FIP), lymphosarcoma, and bacterial infection. Sometimes the cause is unknown. Symptoms of this life-threatening disease include:
- Lethargy
- Weakness
- Breathing difficulties/noisy breathing
- Coughing
- Fainting
Treatments may include antibiotics, draining fluid from the heart, and surgery to remove a portion of the pericardium. With prompt, effective treatment, assuming that the underlying condition is curable, this form of heart disease is often curable as well.
Arrhythmias in Cats
Arrhythmias are abnormalities in heart rate and rhythm, which range from mild to life-threatening. They can be caused by an infection of the heart or other body area, congenital heart defects, heart disease, trauma, cardiovascular neoplasia, endocrine disease, neurological disorders, digestive system diseases, electrolyte disturbance, toxins, medication reactions, and other problems. Symptoms, which can range from mild to severe, may include:
- Weakness that comes and goes
- Tiring easily during routine exercise
- Fainting
- Breathing difficulties
- Coughing
- Abdominal swelling
Treatment varies based on the underlying condition.
Heart problems may also be caused by Heartworm Infection, and there are other conditions that produce symptoms similar to those of heart disease. See Symptoms of Illness in Cats and Kittens for more information.
References:
- Atkins, C.E. (2004). “Feline Hypertrophic Cardiomyopathy.” 29th World Congress of the World Small Animal Veterinary Association. Vin.com.
- Barchas, E. (n.d.). “Heart Disease and Heart Failure in Cats.” DrBarchas.com.
- Kittleson, M.; Gompf, R.; & Little, S. (2006). “Feline Hypertrophic Cardiomyopathy: Advice for Breeders.” Dr. Susan Little’s Website, CatVet.Homestead.com.
- Feinman, J. (1998). “Feline Cardiomyopathy.” HomeVet.com.
- Feline Advisory Bureau. (2008). “Cardiomyopathy in Cats.” FABCats.org.
- Glendal Animal Hospital. (n.d.). “Cardiovascular Disease.” FamilyVet.com. http://www.familyvet.com/Cats/Cardiac.html#chf
- PetMD.com. (2011). “Heart and Lung Diseases in Cats: Endomyocarditis in Cats.”
- Plotnick, A. (2010). “Endocarditis.” PetPlace.com.
- Tilley, L.P. (2008). Manual of Canine and Feline Cardiology. St Louis, MO: Saunders.
- Ware, W.A. (2007). Cardiovascular Disease in Small Animal Medicine. London, UK: Manson Publishing Ltd.
- Ware, W.A. (n.d.). “ Myocardial Diseases of the Cat.” MaxsHouse.com.
- Wingfield, W.E., et al. (2001). Veterinary Emergency Medicine Secrets. Philadelphia, PA: Hanley & Belfus, Inc.
Jennifer Copley - Jennifer Copley, BFA, BEd, has a diverse base of expertise that includes research, writing, education, pet care, and various other ...
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