Heart conditions

Dilated cardiomyopathy

What is Dilated cardiomyopathy?

Dilated cardiomyopathy (DCM) is diagnosed by a enlarged (dilated) and dysfunctional chamber of the heart called the left ventricle. When the chamber stretches out and is not functioning properly it can cause heart failure, an abnormal heartbeat (arrhythmia), and clot formation.

Some basic facts about Dilated cardiomyopathy

About 1 in 2,500-3,000 people have DCM.

DCM is the most common form of cardiomyopathy, although not all of these cases have a genetic cause.

Individuals with DCM may have no symptoms for years. The start of symptoms typically begins later in life, although DCM may be evident at any time of life. Symptoms include: swelling (edema), shortness of breath, fatigue, dizziness or fainting, palpitations, stroke, or blockage of another blood vessel by a clot. DCM may be part of a larger, syndromic condition involving other body systems.

There are several multisystem conditions that can include DCM as a part of the initial clinical presentation. In some individuals and families, it is difficult to distinguish between isolated DCM and DCM that may be caused by an underlying multisystem condition or syndrome.

What causes Dilated cardiomyopathy and how is it diagnosed?

There are many factors that can lead to the development of DCM. Some of these are genetic and others are non-genetic. Non-genetic factors include coronary artery disease, congenital heart disease, thyroid disease, inflammatory conditions, exposure to certain toxins, severe long-standing hypertension, among others. When non-genetic factors have been ruled out as a cause for DCM, an individual is said to have idiopathic DCM. Genetic testing can confirm a genetic cause for individuals with idiopathic DCM. Other factors, such as a family history of DCM or sudden unexplained death, can increase the suspicion for genetic DCM.

Role of genetics in diagnosis

Genetic testing can help establish a diagnosis of genetic DCM and distinguish from other genetic and non-genetic causes of DCM.

Once a genetic cause has been identified, family members may be tested for that cause to know whether or not they are at risk of developing DCM themselves.

A negative genetic test result in an individual with isolated DCM does not mean the individual does not have DCM. It simply means we have not yet identified what caused DCM for this individual. Not all individuals with DCM will have a positive genetic test result.

How is Dilated cardiomyopathy treated?

DCM can be treated through medications, implantation of a pacemaker or other heart rhythm regulator, and/or heart transplant.

Role of genetics in treatment

Identifying the gene associated with an individual’s DCM can help the physician choose the most effective treatment.

How do I arrange for genetic testing?

Your physician will assist you in identifying and arranging for the appropriate genetic test(s). If you have specific questions or concerns about the testing, your physician may refer you to a genetic counselor to discuss further. Once you are ready to proceed with genetic testing, you will need to submit either a blood or saliva sample.