Dilated cardiomyopathy is a disease of the heart muscle that usually starts in your heart’s main pumping chamber (left ventricle). The ventricle stretches and thins (dilates) and can’t pump blood as well as a healthy heart can. Over time, both ventricles may be affected. The term “cardiomyopathy” refers to diseases that affect the heart muscle itself.

Dilated cardiomyopathy might not cause symptoms, but for some people it can be life-threatening. It’s a common cause of heart failure. Dilated cardiomyopathy can also lead to irregular heartbeats (arrhythmias), blood clots or sudden death. The condition can affect anyone, including infants and children.