Heart Murmurs in Cats: What You Should Know About Hypertrophic Cardiomyopathy (HCM)

In hypertrophic cardiomyopathy, the muscular walls of the left ventricle (the main pumping chamber of the heart) become abnormally thick. This reduces the heart’s ability to fill with blood and, over time, can lead to heart failure or dangerous blood clots. HCM is the most common form of heart disease in cats, particularly in breeds like Maine Coons, Ragdolls, and American Shorthairs, but it can affect any cat—purebred or mixed.