Feline hypertrophic cardiomyopathy (HCM) is characterized by an abnormal thickening of the heart muscles. These enlarged muscles significantly inhibit the heart from being able to pump blood efficiently throughout the body, leading to both abnormal heart rhythms and blood-clot formation. It is the most common form of heart disease in cats and is most often diagnosed in young to middle-aged cats. Maine Coons and Ragdolls are predisposed to HCM. It can often present with no other clinical symptoms than sudden death and is often referred to as “silent” cardiomyopathy.


HCM often goes undiagnosed. A heart murmur or abnormal rhythm may be heard by your veterinarian and can sometimes be the first indication of an abnormal heart. Other symptoms include:


If your veterinarian is concerned about a risk for HCM, he or she will likely recommend:


Treatment consists of medical management to try to slow your cat’s heart rate, improve heart function and decrease the risk of blood clot formation. A low sodium diet may also be recommended. In the event that your cat progresses to congestive heart failure, hospitalization may be necessary before the use of other therapies.