Heart disease is a common affliction of domestic cats, affecting an estimated 5-20% of pet cats. While often seen as disease of older cats, it can affect animals at any stage in life. While not a curable condition, heart disease in cats can be managed well and cats with heart failure can maintain an excellent quality of life. While there is a link between heart murmurs and heart disease, it is important to remember that not all cats with murmurs will have heart disease and not all cats with heart disease have a murmur.
Types of Heart Disease
The most common type of heart disease in cats today is referred to as “Hypertrophic Cardiomyopathy”, or HCM. This disorder is characterized by thickening of the heart muscles leading to less ability to pump blood. There is a known genetic component to the development of HCM, however environmental factors and concurrent diseases (such as hyperthyroidism) also play a role.
More rare forms of heart disease in cats include “Dilated Cardiomyopathy” or DCM, which is generally caused by poor diet; particularly a deficiency of the amino acid taurine. While previously common, modern diets have virtually eliminated this as a clinical disease.
Restricted and undifferentiated cardiomyopathy, valvular disease, and congenital heart disease are all uncommon causes of heart failure in cats.
The diagnosis of heart disease is based partially on clinical signs, including presence of a heart murmur, difficulty breathing, poor blood flow, and a history of weakness, fainting, or lethargy. Genetic testing is available to predict the onset of heart disease in some breeds, such as the Maine Coon and the Ragdoll. Other cat breeds that are predisposed to heart disease include the Sphinx and Devon Rex, however testing is not available for these breeds.
A blood test called “NT-proBNP” can be used to detect early heart disease in some cats, however it is not commonly used as a first line diagnostic tool.
X-Rays of the chest can be used to detect some types of heart disease and are an excellent tool for highlighting associated conditions such as fluid in or around the lungs, or dilated blood vessels.
The best tool for the diagnosis, characterization, and prognosis for heart disease is ultrasound of the heart, known as “echocardiography”. This allows the measurement of chamber dimensions, outflow obstruction, and other values that can be used to tailor medication protocols and predict survival times.
Management and Prognosis
As in humans, there is no medical cure for most types of heart disease. While some uncommon types may be fixed by diet or surgery, management of most heart disease in cats is focused on reducing symptoms and supporting quality of life.
The choice of which drugs to use in the management of heart disease varies widely between veterinarians, as there is very little good data available on long term survival of heart disease in cats. There are, however, several classes of drug that are commonly used including beta-blockers, diuretics, ACE-Inhibitors, and anti-thrombotics. It is essential to talk with your veterinarian about their choice of therapy and ensure it is the best plan for your cat. Here at the Village Cat Clinic we ensure each cat’s protocol is tailored to their individual needs.
Cats diagnosed with heart disease have a widely varying prognosis depending on the stage at which they are diagnosed. Sub-clinic cats may survive for many years; however cats in Congestive Heart Failure generally do not survive more than a few months. Blood clots are also a major risk in cats with heart disease and are a common cause of end-of-life decisions.
Written by Dr.Matthew Kornya