Cardiomyopathy describes any disorder that affects the heart muscle, causing the heart to lose its ability to pump blood effectively. In some instances, the heart rhythm also becomes disturbed and leads to arrhythmias (irregular heartbeats). There may be multiple causes of cardiomyopathy, including viral infections and certain medications. Often, the exact cause of the muscle disease is never found.
Cardiomyopathy differs from many of the other disorders of the heart in several ways, including the following:
- Cardiomyopathy can, and often does, occur in the young.
- The condition tends to be progressive and sometimes worsens fairly quickly.
- It may be associated with diseases involving other organs, as well as the heart.
- Dilated cardiomyopathy is a leading cause for heart transplantation.
Viral infections that infect the heart are a major cause of cardiomyopathy. In some instances, cardiomyopathy is a result of another disease or its treatment, such as complex congenital (present at birth) heart disease, nutritional deficiencies, uncontrollable, fast heart rhythms, or certain types of chemotherapy for cancer. Sometimes, cardiomyopathy can be linked to a genetic abnormality. Other times, the cause is unknown. Three types of cardiomyopathy typically affect adults.
Hypertrophic cardiomyopathy occurs when the muscle of the left ventricle of the heart becomes thicker than normal, obstructing blood flow to the rest of the body. Hypertrophic cardiomyopathy can affect the heart's mitral valve, causing blood to leak backward through the valve.
- This is a rare disease and in most cases is inherited.
- It can affect men and women of all ages, and symptoms can appear in childhood or adulthood
- Symptoms include shortness of breath on exertion, dizziness, fainting, and angina pectoris.
- Some patients experience cardiac arrhythmias, which may lead to sudden death.
Dilated cardiomyopathy is the most frequent form of nonischemic cardiomyopathy. The cavity of the heart becomes enlarged and stretched, compromising the heart's ability to pump normally:
- This occurs most often in adults ages 20 to 60 and more often in men than women, but has been diagnosed in people of all ages, including children.
- Most patients eventually develop congestive heart failure.
- Dilated cardiomyopathy can be caused by chronic, excessive consumption of alcohol and nutritional deficiencies associated with alcoholism.
- It occasionally occurs as a complication of pregnancy and childbirth.
- Other possible causes include: various infections (mostly viral, which lead to inflammation of the heart muscle, called myocarditis), illicit drugs, and (rarely) heredity. Sometimes medications used to treat a different medical condition can damage the heart and produce dilated cardiomyopathy. However, in most cases, a specific cause for the damage is never identified.
Restrictive cardiomyopathy, the least common type of cardiomyopathy in the U.S., occurs when the heart muscle becomes excessively rigid and unable to fill with blood properly:
- It often occurs due to an underlying disorder, such as hemochromatosis, scleroderma, or sarcoid.
- Restrictive cardiomyopathy does not appear to be inherited, but some of the diseases that lead to the condition are genetically transmitted.
- Symptoms may include fatigue, swelling of the extremities, and difficulty breathing on exertion.
ARVD is a rare type of cardiomyopathy that occurs if the muscle tissue in the right ventricle dies and is replaced by scar tissue:
- This process disrupts the heart's electrical system, causing arrhythmias.
- It usually affects teens and young adults
- Symptoms include heart palpitations and fainting after physical activity.
- It can cause sudden cardiac arrest in young athletes.
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