The heart is a muscle not entirely unlike the rest of the muscles in your body. Myopathy means disease or dysfunction of muscle, cardiomyopathy therefore means dysfunction of the heart muscle. In Dilated Cardiomyopathy this dysfunction causes the heart to stretch and become too floppy and loose to pump effectively. The heart can stretch to a certain point but beyond that it becomes like an overstretched spring. There are a wide range of causes of Cardiomyopathy which your cardiologist will explore. Treatment will depend on the cause.