What is cardiomyopathy?
Cardiomyopathy is a disease in which the heart muscle becomes inflamed and doesn't work as well as it should. There are multiple potential causes. Cardiomyopathy can be classified as primary or secondary. Primary cardiomyopathy - also known as idiopathic cardiomyopathy - can't be attributed to a specific cause, such as hypertension (high blood pressure), heart valve disease, coronary artery disease or congenital heart defects (birth defects). Secondary cardiomyopathy is due to specific causes and is often associated with diseases involving other organs as well as the heart. There are three principal types of cardiomyopathy -- dilated, hypertrophic and restrictive.
What is dilated (congestive) cardiomyopathy?
This is the most common form. The heart cavity is enlarged and stretched (cardiac dilation) in contrast to the thickening of the walls in the hypertrophic form. The heart is weak and doesn't pump normally, and most patients develop congestive heart failure. Arrhythmias and disturbances in the heart's electrical conduction also may occur.
How is dilated or congestive cardiomyopathy treated?
There are several medications used in the treatment of cardiomyopathy including:
Heart rhythm disturbances (arrhythmias) may require antiarrhythmic drugs. More rarely, "heart block" may develop, requiring an artificial pacemaker. If the person is young and otherwise healthy, and if the disease gets worse, a heart transplant may be considered.
What is hypertrophic cardiomyopathy?
In this condition, the muscle mass of the left ventricle enlarges or "hypertophies." In one form of the disease, the wall between the two ventricles (septum) becomes enlarged and obstructs the blood flow from the left ventricle. The syndrome is known as hypertrophic obstructive cardiomyopathy (H.O.C.M.) or asymmetric septal hypertrophy (A.S.H.). It's also called idiopathic hypertrophic subaortic stenosis (I.H.S.S.).
Besides obstructing blood flow, the thickened wall sometimes distorts one leaflet of the mitral valve, causing it to leak. In over half the cases, the disease is hereditary. Close blood relatives (parents, children or siblings) of such persons often have enlarged septums, although they may have no symptoms. This disease is most common in young adults. In the other form of the disease, non-obstructive hypertrophic cardiomyopathy, the enlarged muscle doesn't obstruct blood flow.
The symptoms of hypertrophic cardiomyopathy include shortness of breath on exertion, dizziness, fainting and angina pectoris (chest pain or discomfort caused by reduced blood supply to the heart muscle). Some people have cardiac arrhythmias, abnormal heart rhythms that in some cases can lead to sudden death. The obstruction to blood flow from the left ventricle increases the work the ventricle must do, and a heart murmur may be heard.
How is hypertrophic cardiomyopathy treated?
A drug known as a beta-blocker (such as propranolol) or a calcium channel blocker is the usual treatment. If a person has an arrhythmia, an antiarrhythmic drug may also be used. Surgical treatment of the obstructive form is possible in some cases if the drug treatment fails.
Alcohol ablation is another nonsurgical treatment being developed for hypertrophic obstructive cardiomyopathy. It involves injecting alcohol down a small branch of one of the heart arteries to the extra heart muscle. The procedure results in the extra heart muscle being destroyed without having to cut it out surgically.
People undergoing this procedure usually suffer chest pain during the alcohol injection. The alcohol can also disrupt normal heart rhythms and require the insertion of a pacemaker. Alcohol ablation is a relatively new procedure being performed at only a few specialized centers in the United States. However, it's too soon to know whether this treatment will result in long-term benefit. It's still considered experimental.
What is restrictive cardiomyopathy?
This is the least common type in the United States. The myocardium of the ventricles becomes excessively "rigid," so it's harder for the ventricles to fill with blood between heartbeats. A person with restrictive cardiomyopathy often complains of being tired, may have swollen hands and feet, and may have difficulty breathing on exertion. This type of cardiomyopathy is usually due to another disease process.