cardiomyopathy - types and causes

Cardiomyopathy (types and causes)

Definition - Cardiomyopathy is a weakening of the heart muscle or a change in heart muscle structure. The heart muscle becomes inflamed and doesn’t work as well. As a result, it is often associated with inadequate heart pumping or other heart function abnormalities and diseases associated with other organs as well.

Causes (general):
Cardiomyopathy can be caused by viral infections, heart attacks, ALCOHOLISM, long-term, severe high blood pressure, nutritional deficiences (particularly selenium, thiamine, and L-carnitine), systemic lupus erythematosus, celiac disease, and end-stage kidney disease.

Types:
Dilated cardiomyopathy
Hypertrophic cardiomyopathy
Restrictive cardiomyopathy

Dilated Cardiomyopathy
This is the most common form, usually idiopathic myocardial disorder characterized by a marked enlargement and inadequate function of the left ventricle. Most patients develop CONGESTIVE HEART FAILURE. Arrhythymias and disturbances in the heart’s conduction system may also occur.

Blood flows more slowly in an enlarged heart so blood clots easily form. Complications:
- Thrombus and mural thrombi
- Embolus (pulmonary, cerebral, renal, peripheral, coronary artery)

A complication known as Barth’s syndrome (genetically linked cardiac disease) can cause dilated cardiomyopathy.

If the heart is significantly stretched, the mitral and tricuspid valves may not be able to close properly resulting in murmers. Blood pressure may increase because of increased sympathetic activity. Sympathetic nerves can also cause arteries to narrow. That’s why some people have high blood pressure readings.

Dilated cardiomyopathy accounts for over 10,000 deaths each year. Nearly 50,000 people a year are hospitalized due to this condition. The condition may not produce symptoms in some people, or it may be so severe that heart failure develops, which may require a heart transplant.

Dilated cardiomyopathy includes many conditions:
Causes (specific):

• Ischemic cardiomyopathy: This is caused by heart attacks, which leave scars in the heart muscle (myocardium).
• Idiopathic cardiomyopathy: The term "idiopathic" means that the cause is unknown.
• Hypertensive cardiomyopathy: This is seen in people who have high blood pressure for a long time, particuarly when it has gone untreated for years.
• Infectious cardiomyopathy: HIV, Lyme disease, Chagas disease, viral myocarditis, and other infections have been linked to dilated cardiomyopathy.
• Toxic cardiomyopathy: In additional to alcohol, cocaine use, and some chemotherapy drugs can also produce dilated cardiomyopathy.
• Peripartum cardiomyopathy: This type appears in women during the last trimester of pregnancy or after childbirth.
• Tachycardia mediated cardiomyopathy: This occurs in people who have an abnormally fast heart rate.
• Alcoholic cardiomyopathy:
o This type of dilated cardiomyopathy usually begins about 10 years after sustained, heavy alcohol consumption.
o It can occur with both typical signs of heart failure, as well as with atrial fibrillation or other heart rhythm problems.
In severe cases, the lack of blood flow affects all parts of the body, damaging multiple tissues and organ systems. Also damages the liver.

Other types:
• Hypertrophic cardiomyopathy: This occurs when the left and right heart muscles grow to be different sizes. In up to 70% of cases, there is a family history of this condition.
• Restrictive cardiomyopathy: This disorder affects the heart muscle's ability to relax between contractions. The heart cannot relax adequately after each contraction (systole), which prevents it from filling with enough blood.

~Shantz

Sources: www.americanheart.org/presenter.jhtml?identifier=4468
http://nlm.nih.gov/medlineplus/ency/article/001105.htm