Signs and Diagnosis
Increased heart rate and a heart murmur are common signs of HCM. Other signs include decreased appetite, weight loss, and an increase in respiratory rate. Unfortunately these signs are quite vague and may not lead one to an HCM diagnosis. While the appearance of a blood clot and a heart murmur may be a first sign, some cats will not show any of these signs. The first sign may be congestive heart failure or sudden death. An echocardiogram can confirm a HCM diagnosis by illustrating a thickened-left ventricle.
Unfortunately, there is not a proven therapy available for the slow progression of this disease. There are many medications that have a theoretical basis in slowing progression. If your cat only has a mild case, there is no risk of congestive heart failure or clot formation and the risk of sudden death is miniscule. If your cat has moderate or severe hypertrophic cardiomyopathy, there is a risk for both congestive heart failure and clot formation, although clot formation is less common. These cats should be monitored for any change in breathing (too fast or labored). If this occurs, a chest X-ray should be taken as soon as possible to evaluate for the presence of congestive heart failure.
When and if congestive heart failure develops, there are medications such as diuretics to help control it. Medications to help prevent blood clots, such as aspirin and Plavix (clopidogrel), are often prescribed when the upper chambers of the heart become enlarged, although these medications don’t completely eliminate the possibility of clot formation. Despite the risk for these complications, most cats with this disease have an excellent quality of life and do not realize they are sick.
While many afflicted cats never develop problems with HCM, it is very important to monitor these patients closely at home and have them periodically evaluated so that if changes occur, appropriate therapy is prescribed.