Heart disease can be a silent killer of cats just as it is in people. Cats can be without any apparent signs of problems and then die suddenly from a condition called cardiomyopathy. Cardiomyopathy is disease of the heart muscle. If the heart muscle stops contracting properly, it can result in death. Cardiomyopathy occurs in purebred and mixed breed cats, and signs include heart murmur, coughing, exercise intolerance, restlessness, abnormal resting postures, and open mouth breathing.
There are certain breeds of cats that have genetic predispositions to heart disease and these include Maine Coons, Ragdolls, Sphynx, and British Shorthairs. Knowledgeable breeders have their cats tested and only breed cats that are free of disease or do not carry the bad genes. There are specific DNA tests for cardiomyopathy in Maine Coon and Ragdoll cats. Historically the only way to screen for cardiomyopathy was through an echocardiogram, an ultrasonic examination of the heart.
If a veterinarian hears a heart murmur during a routine examination, she is unable to tell just by the sound, whether there is any functional disease of the heart. The next diagnostic step is to take chest x-rays and assess the size and shape of the heart, as well as the lungs and airways. If abnormalities are found on the x-rays, an echocardiogram is recommended. An echocardiogram shows how the blood is flowing through the heart, the thickness of the muscle walls, the size of the heart chambers, the valve function, and if there are any other structural problems.
Genetics, obesity, high blood pressure, kidney disease, and hyperthyroidism can all affect the heart and lead to cardiac problems. Genetics are the most common cause of heart disease in young cats, but in cats 9 years and older, other conditions more frequently lead to heart disease.
About 18 months ago, one of the large national veterinary reference laboratories developed a blood test to screen cats for cardiomyopathy. The Cardiopet proBNP test detects a biomarker that is linked to increased cardiac stretch. I think this test is a valuable screening test for cats since it is easy to perform through a blood sample and less costly as a preliminary test than x-rays or echocardiogram. If the test is abnormal, the other tests will still be needed to fully evaluate the heart’s problem.
At my clinic we use the test when we detect heart murmurs in otherwise young, healthy cats. We have also made it part of our senior cat health plans. We screen for heart disease in the same blood panel that checks the blood cell count, liver and kidney function, electrolytes, blood sugar, and thyroid. The test is also useful to determine whether disease in the chest cavity is due to heart or to respiratory problems.
Cardiomyopathy does not have a cure, but there are treatments that decrease stress on the heart and promote its function. Cardiomyopathy puts cats at higher risk for tolerating anesthesia and certain other medications, so knowing that it is present allows a veterinarian to make important modifications to therapies. Humans with significant cardiomyopathy get heart transplants, but that procedure is not currently an option for cats.
Written by Dr. Wexler-Mitchell of The Cat Care Clinic in Orange, CA
Copyright © 2011 The Cat Care Clinic