A dilated cardiomyopathy (DCM) is a condition where the heart muscle is enlarged and weakened to the point where it cannot pump adequate oxygen-rich blood to the body. DCM can occur in anyone but it is most commonly found among adult men. DCM is the most common cause of heart failure.

A number of conditions may cause DCM, including:

In some cases, there is no known cause (idiopathic).

Dilated cardiomyopathy is the most common type of cardiomyopathy and derives its name for the following reasons:

• Dilated refers to the dilation or enlargement of one or both lower chambers of the heart ventricles. The dilation frequently begins in the heart’s main pumping chamber, the left ventricle. This chamber is responsible for pumping oxygen-rich blood from the heart to the rest of the body. As it grows, it starts to weaken. Its weakened condition often leads to heart failure.
  
  
• Cardiomyopathy is any disease of the heart muscle. It is most often used to refer to a heart that is abnormally enlarged, thickened and/or stiffened.

Symptoms of DCM generally vary depending on the severity of the condition. In the early stages, the patient may not experience any symptoms as the heart adjusts to the disease. However, if left untreated, DCM can result in arrhythmia, blood clots and heart failure. Therefore, later stages of DCM can present symptoms such as fainting, palpitations, chest pain, fatigue and shortness of breath.

Treatment for DCM usually begins by attempting to treat the underlying condition. If it is caused by coronary artery disease, for example, the physician may first attempt to treat that condition with medications and lifestyle changes. However, a significant number of dilated cardiomyopathies have no known cause, so physicians must attempt to alleviate symptoms and stop the progressive degeneration of the heart. This approach might include strategies that aim to do the following:

• Strengthen the heart
• Decrease the heart’s workload
• Allow the heart to shrink in size
• Lower blood pressure (if necessary)
• Control abnormal heart rhythms (arrhythmias) 

A pacemaker or implantable cardioverter defibrillator may be surgically inserted to control arrhythmias that do not respond to medication. As a last resort, a heart transplantation may be considered. Other techniques to treat this condition are currently being developed.