Dilated cardiomyopathy (DCM) used to be a disease that was poorly understood, with few treatment options and limited outcomes. Today, things are very different. Advances in medications, devices, transplantation, and genetics have expanded treatment choices, improved outcomes, and given patients new hope for the future. Knowing why you developed DCM helps your medical team determine the most effective treatment plan for you.
Ischemic DCM (Heart Attack–Related) | ~50–60% of cases
This is the most common cause of DCM.
About 50% to 60% of all DCM cases in the U.S. result from heart muscle damage caused by a heart attack from coronary heart disease.
Coronary artery disease occurs when the blood vessels supplying the heart (coronary arteries) become narrowed with cholesterol plaque. If a plaque ruptures, blood and oxygen flow to the heart muscle is blocked (ischemia), causing part of the heart muscle to die. The remaining heart muscle weakens and enlarges over time, leading to DCM.
This type of DCM is specifically called ischemic dilated cardiomyopathy.
Non-Ischemic DCM (Not Caused by Blocked Arteries) | ~40–50% of cases
When coronary artery disease and prior heart attacks are ruled out, DCM is called non-ischemic dilated cardiomyopathy.
This category includes several different causes, including:
- Idiopathic (unknown cause)
- Genetic or familial DCM
- Viral or inflammatory causes
- Toxins (such as certain chemotherapy drugs or alcohol)
- Metabolic conditions (such as thyroid disease)
- Valve or congenital heart disease
- Iron overload in the heart muscle
The most common form of non-ischemic DCM is idiopathic DCM.
Idiopathic DCM (Cause Not Yet Identified)
“Idiopathic” means the exact cause has not yet been identified.
A diagnosis of idiopathic DCM is made only after other known causes are ruled out, including coronary artery disease and other medical conditions such as:
- Heart valve problems or congenital heart disease
- Toxic causes, such as certain chemotherapy drugs
- Metabolic issues, such as thyroid disease
- Infection
- Iron overload in the heart muscle
People with idiopathic DCM typically have similar symptoms and age of onset as those with DCM from other causes.
Importantly, research now shows that many idiopathic cases are actually genetic. Studies suggest that 35–50% of people diagnosed with idiopathic DCM may have an inherited form.
Familial (Genetic) Dilated Cardiomyopathy
Many cases originally diagnosed as Idiopathic Dilated Cardiomyopathy (IDC) are actually genetic. When DCM affects two or more family members, it is classified as Familial Dilated Cardiomyopathy (FDC).
Researchers have identified 70+ gene mutations associated with inherited DCM.
First-degree relatives (parents, siblings, or children) may have up to a 50% chance of carrying the same genetic variant.
Next Steps for You and Your Family
Talk with your cardiologist or a genetic counselor about genetic testing. Identifying a mutation can influence treatment decisions and guide monitoring.
First-degree relatives should consider baseline heart screening, including:
- ECG (EKG)
- Echocardiogram
Visit www.geneticcardiomyopathy.org for more information about genetics and DCM.
Genetic Testing
Several genetic cardiomyopathy testing options are available, including no-cost testing for qualified individuals. For more information, please visit: https://geneticcardiomyopathy.org/testing/get-tested/
Pregnancy and DCM (PPCM)
Peripartum cardiomyopathy (PPCM), also called pregnancy-associated cardiomyopathy, is a form of DCM that occurs during pregnancy or in the months following delivery.
The exact cause is not always known, but genetic factors may play a role.
Because of this, women diagnosed with PPCM, and their first-degree relatives, should consider the same heart screening recommendations used for familial DCM.
Next Steps for You and Your Family
Because many cases of “unknown” DCM are now linked to genetics, screening and early detection are powerful tools for protecting your family’s heart health.
View Screening Recommendations for FamiliesFor more information, visit: Genetic Cardiomyopathy Awareness Consortium