Cardiomyopathy Health Article

Definition

Cardiomyopathy is a weakening of the heart muscle or a change in heart muscle structure. It is often associated with inadequate heart pumping or other heart function abnormalities.

Causes, incidence, and risk factors

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.

Specific types of cardiomyopathy include:

• Dilated cardiomyopathy: This is a global, usually idiopathic myocardial disorder characterized by a marked enlargement and inadequate function of the left ventricle. It may affect young people. Dilated cardiomyopathy includes many conditions:
  • 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.
  • Alcoholic cardiomyopathy: This type of dilated cardiomyopathy usually begins about 10 years after sustained, heavy alcohol consumption. It can occur with both typical signs of heart failure, as well as with atrial fibrillation or other heart rhythm problems.
  • 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.
• 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.

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.

Symptoms

• Shortness of breath (dyspnea)
  • Need for extra pillows to sleep - lying flat causes shortness of breath
  • Waking up at night with sudden shortness of breath (paroxysmal nocturnal dyspnea)
• Cough - may be caused by extra liquid accumulating in the lungs, secondary to heart failure
• Fatigue (decreasing ability to tolerate physical exertion)
• Swelling of legs or ankles (edema)
• Abdominal swelling
• Chest pain - also known as "angina," consists of a feeling of sharp, unrelenting pressure the middle of the chest (more common in ischemic cardiomyopathy)
• Palpitations - the sensation of feeling the heart beat
• High blood pressure
• Fainting - especially after activity; temporary and brief loss of consciousness
• Light-headedness - especially after activity
• Dizziness
• Low amount of urine during daytime
• Need to urinate at night
• Difficulty concentrating
• Decreased alertness
• Loss of appetite
• Deconditioning may occur as a consequence of the other symptoms, leading to a reduction in the heart's muscle mass

Signs and tests

Examination may reveal an irregular heartbeat. Heart sounds and breath sounds may be abnormal. When heart valve disease is also present, a heart murmur may be detected. Additionally, there may be other signs of heart failure.

Decreased heart function and heart enlargement may appear in these tests:

• Coronary angiography
• Echocardiogram and ultrasound examination of the heart.
• Chest x-ray
• Chest CT scan
• MRI of chest
• ECG

Rarely, a heart biopsy performed during a heart catheterization may be needed to rule out other disorders. The following lab tests may be used to rule out other disorders and to assess the condition of the heart:

• CBC
• Coronary risk profile
• Blood chemistries
• Cardiac enzymes: (CPK isoenzymes, CK-MB, LDH isoenzymes)
• Toxic screen for cocaine