Monday, August 16, 2010

Your cat has a heart murmur, now what?

Your cat seems to be doing great at home and you realize its time for the annual trip to the vet. During the exam, everything seems to be good, except that your veterinarian mentions that a heart murmur is present. You most likely wonder what this finding means for you and your cat as well as what the next steps are in figuring out the cause of the heart murmur. In this article I will discuss the tests necessary when a heart murmur has been identified in your cat by your veterinarian when they are not showing any clinical signs of heart disease (asymptomatic).

Once a murmur has been indentified in your cat, your veterinarian will want to obtain a blood and urine sample. Anemia and hyperthyroidism may be the cause of the heart murmur and are quickly and easily identified with blood tests. A blood pressure should also be obtained, as an elevation may also have secondary effects on the heart.

X-rays (radiographs) of the chest are important as they not only reveal changes to the general size/shape of the heart, but also changes to the lungs and blood vessels. It is important to remember that normal size/shape of the heart on x-rays does not mean that there is no heart disease, it may signal that only minimal changes to the heart have occurred so far. It is also important to remember that changes on the x-rays do not tell you the type of heart disease present.
An electrocardiogram (ECG) of the heart may be obtained as well, especially if abnormal heart beats (an arrhythmia) are noted when the veterinarian is listening to the heart.

New blood tests that measure specific markers in the blood that may indicate the presence of heart disease (cardiac biomarkers) have recently become available. These tests may help strengthen the suspicion of underlying heart disease.
The gold standard (best test) for diagnosing heart disease or excluding serious disease is an ultrasound of the heart (echocardiogram). This special ultrasound is performed by a heart specialist (board certified cardiologist). The ultrasound will reveal if the heart muscles are abnormally thickened, if there is something obstructing the flow of blood, any defects within the heart and the size of the different heart chambers among other things. Of cats with heart disease, the most common form is hypertrophic cardiomyopathy (HCM). This is thickening of the heart muscle due to an abnormality in the muscle.

Your veterinarian can help you schedule an appointment with a veterinary specialist . Besides performing the special ultrasound of the heart, the veterinary specialist can also obtain any tests that your veterinarian was not able to perform. Make sure that you have any blood tests, x-rays, ECG and a copy of the medical records during your consultation. There is nothing more frustrating for the veterinary specialist (or you) than to not have all the test results needed in order to provide you with the best information as to what is affecting your cat.

Remember, just because your cat has a heart murmur it does not necessarily mean that your cat has severe heart disease. The best news the veterinary heart specialist can give you is that the murmur is not a cause for concern! If the murmur is significant, your cat can receive the proper treatments and have a follow-up plan made to try and stay ahead of any major changes. It is better to find out what is wrong before hand, than be surprised in the middle of the night and have to rush to the emergency room.