Hypertrophic cardiomyopathy is a form of acquired disease of the heart muscle seen most commonly in cats, and less commonly in dogs. While there can be environmental, nutritional and medical causes of some forms of cardiomyopathy, the most common cause in both dogs and cats is genetic in origin. Some cats with hyperthyroidism also can on occasion develop cardiomyopathy, which will often resolve once the overactive thyroid is addressed.
Symptoms of hypertrophic cardiomyopathy can vary, and may include sudden difficult breathing due to congestive heart failure, as well as nonspecific symptoms of loss of appetite, vomiting and changes in behavior. In some cases, blood clots may form and lead to sudden paralysis of most commonly the hind legs. Some patients with cardiomyopathy may develop abnormal heart rhythms, which may predispose some pets to a risk of sudden death without any symptoms appearing beforehand.
While it is sometimes possible to diagnose cardiomyopathy through a combination of physical exam, x-rays and an EKG, often a cardiac ultrasound is needed to document the severity and form of cardiomyopathy present. This echocardiogram is most helpful in defining long term treatment plans, as well as allowing us to determine the progression and prognosis of the heart condition.
Treatment of hypertrophic cardiomyopathy usually involves drugs such as Lasix or Furosemide to reduce fluid buildup, as well as other medications such as Enalapril to help dilate blood vessels and ease the workload on the heart. Sometimes low-dose baby aspirin is used to help lessen the likelihood of future blood clots developing. Most patients with hypertrophic cardiomyopathy will need periodic monitoring by the veterinarian through x-rays and/or echocardiogram. Prognosis will vary with earlier diagnosis and treatment having a better long term prognosis than those pets presenting with hind leg paralysis or congestive heart failure.