Reviewed by Brian R. Robinson, MDCardiomyopathies are a group of conditions where the heart muscle enlarges so that its function is impaired. Symptoms and causes of cardiomyopathy are often similar to those of heart failure, and cardiomyopathy can cause heart failure. Men and African Americans are particularly at high risk.
There are two types of cardiomyopathy, ischemic and nonischemic. Ischemic is caused by a lack of oxygen in the heart generally due to coronary artery disease. The heart muscle enlarges (strengthens) because the lack of oxygen forces it to do extra work.
Nonischemic cardiomyopathy can be further broken down into three categories:
- Dilated Congestive Cardiomyopathy
- Hypertrophic Cardiomyopathy
- Restrictive Cardiomyopathy
Eighty seven percent of non-ischemic cardiomyopathies are dilated. In a patient with dilated cardiomyopathy, inadequate supply of blood, rather than oxygen, injures parts of the heart. The left ventricle, whose job it is to pump blood from the heart and lungs into the rest of the body, stretches to compensate for this lack. If it does not succeed, you have an enlarged, yet weakened muscle. Though dilated cardiomyopathy begins in the left ventricle, it can and often does spread to the entire heart. Dilated congestive cardiomyopathies usually result in congestive heart failure. Causes include:
- Coronary Artery Disease
- Anemia
- Use of alcohol or certain drugs such as cocaine
- A rare complication of pregnancy
- Viral infection such as tuberculosis or HIV
- Hereditary factors
Symptoms of dilated cardiomyopathy are similar to those of heart failure:
- Shortness of breath
- Tiring easily
- Flu-like symptoms
- Fluid retention in legs, abdomen and lungs
- Abnormal heart rhythm
Seventy percent of patients with dilated cardiomyopathy die within five years. Women survive twice as long as men, and whites survive twice as long as blacks. Half of the deaths are sudden, resulting from arrhythmia.
Hypertrophic cardiomyopathy is a thickening of the ventricle walls. Unlike the other types of cardiomyopathy, this one is caused only by genetic defect. When the ventricle walls thicken, the heart cannot properly fill with blood. Blood and fluid backs up in the lungs, causing shortness of breath. Other symptoms include irregular heartbeat, chest pain and faintness. Death from hypertrophic cardiomyopathy is usually sudden, rarely resulting from chronic heart failure.
Restrictive cardiomyopathy is the least common form, and is caused by lifestyle factors or previous heart injury. In this condition, the ventricle walls do not thicken but they stiffen, so they cannot properly expand to fill with blood. This can lead to
congestive heat failure. As with dilated cardiomyopathy, 70% of patients die within five years.
To diagnose a cardiomyopathy, a doctor will use many of the standard tools for examining the heart. First, he or she will listen to the heart with a stethoscope. This may provide an accurate diagnosis as some cardiomyopathies, especially hypertrophic and dilated, yield distinctive heart beats. The diagnosis will be confirmed and more information gathered with a CT (CAT) Scan, MRI, chest x-ray, echocardiogram or electrocardiogram. Biopsy or cardiac catheterization may also be necessary.Treatment depends on the underlying cause. If alcohol or drug use is the cause, the patient should abstain. If a sedentary lifestyle and poor eating habits have caused the problem, as is often the case with ischemic cardiomyopathy, then a lifestyle change is necessary to extend life. Drugs such as beta-blockers and calcium channel blockers reduce the heart’s resistance to expanding and contracting.
If that treatment is not enough, surgery may be warranted. Bypass surgery and coronary stent implantation can be used for ischemic cardiomyopathy. Surgery can relieve the symptoms of hypertrophic cardiomyopathy but it cannot cure it. Heart transplants are also an option; dilated cardiomyopathy is the most common reason for heart transplants. You can learn more about transplants and the recent successful artificial heart transplant by doing a search at the top of the page.
