Dilated cardiomyopathy (DCM) is a condition in which the heart becomes enlarged and cannot pump blood efficiently. The decreased heart function can affect the lungs, liver, and other body systems. br DCM is one of the cardiomyopathies, a group of diseases that affect primarily the heart muscle. Different cardiomyopathies have different causes and affect the heart in different ways. In DCM a portion of the myocardium is dilated, often without any obvious cause. Left or right ventricular systolic pump function of the heart is impaired, leading to progressive heart enlargement via ventricular hypertrophy and ventricular dilation, a process called ventricular remodeling.