Hypertrophic Cardiomyopathy (HCM) is the most common acquired heart disease in cats, but rare in dogs. HCM is a primary heart muscle disease where the muscle walls thicken.
What causes HCM?
Similar to humans, cardiomyopathy appears to be a genetic disorder. Cats are usually middle aged or older when signs emerge, however, the disease can be diagnosed at any age, often less than 5 years in purebred cats.
What are the consequences of a thickened heart?
The degree of thickening ultimately determines the severity of the disease. As HCM develops, the structure and function of the heart are changed:
- The wall becomes less flexible.
- The ventricle is prevented from relaxing and stretching to fill with blood.
- A bottleneck is created, where pressure backs up.
- This eventually leads to heart failure.
- Thickening can also lead to arrhythmia (abnormal heart beat) and sudden death.
- HCM is diagnosed using an ultrasound.
- Clinical signs can include open mouth breathing and lethargy.
- Some cats show no signs at all until very late stages.
- There is currently no cure for this HCM, but it can be managed with drugs that can relax the heart muscle and control heart rate and effort.