Also known as a congestive cardiomyopathy, a dilated cardiomyopathy (DCM) is a condition in which one or both ventricles of the heart becomes enlarged (dilated). This condition often begins in the left ventricle, which is the heart’s main pumping chamber. If it is left untreated, it may also affect the right ventricle. Over time, the entire heart may become enlarged.

Dilated cardiomyopathy can be a life-threatening condition. Aside from the heart’s inability to effectively pump oxygen-rich blood around the body, dilated cardiomyopathy also increases the risk of numerous health conditions, including:

• Blood clots. The extra volume of blood flowing to and from the heart means that the blood flows more slowly. The allows blood clots to form easily and raises the risk of an embolism occurring.
  
  
• Arrhythmia. Abnormal heart rhythms are common in patients with dilated cardiomyopathy. The change in heart structure affects the way that the electrical signals regulating the heartbeat travel through the heart. This may result in tachycardia (increased heartbeat) or bradycardia (decreased heartbeat).
  
  
• Heart valve problems. Other structures in the heart may struggle to cope with the extra size of the ventricles and the extra blood that is being processed. This may cause problems with the heart’s valves. The valves most often affected are the mitral valve between the left atrium and the left ventricle, and the tricuspid valve between the right atrium and the right ventricle. This can lead to further worsening of heart failure and reduction of effective heart output.

The end result of untreated dilated cardiomyopathy is usually heart failure. Heart failure occurs when the heart is unable to cope with the body’s demand for oxygen-rich blood. This eventually causes complications with the lungs and other parts of the body. Heart failure may lead to cardiac arrest, where the heart stops pumping altogether.

Dilated cardiomyopathy can occur to anyone at any age, although it is more common in people aged 20 to 60 years, according to the National Institutes of Health. It occurs more often in men than women. In some cases, there is an underlying cause for a patient’s dilated cardiomyopathy, which may or may not be treatable. However, in a significant number of cases, no cause can be found. In this instance, it is referred to as idiopathic cardiomyopathy.