ADAM Health Encyclopedia

Cardiomyopathy

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

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

Exams 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

Treatment

While all types of cardiomyopathy can cause heart failure, each case requires specific strategies for recovery. Heart failure is treated with a vigorous blend of patient education, dietary changes, and medications.

Possible medications include:

• Positive inotropic medications: These medicines help the heart contract. Digoxin is one type of positive inotropic medication. It is no longer widely used, except in cases complicated by atrial arrhythmias. Other medicines have replaced digoxin. Positive inotropic medications given to patients in the hospital include dopamine, dobutamine, and milrinone.
• Diuretics: Often called "water pills," diuretics help relieve the fluid overloads in heart failure.
• Vasodilators: These drugs dilate blood vessels at several levels in the body, reducing the workload for the heart.
• ACE-inhibitors and angiotensin receptor blockers (ARBs): These drugs have been shown to improve survival and reduce heart-related complications.
• Aldosterone blockers: These drugs help balance electrolytes in the body. Studies have shown that aldosterone blockers can improve survival in patients who have a heart attacked complicated by cardiomyopathy.
• Beta blockers: In the past, these drugs were not recommended for those with cardiomyopathy. However, beta blockers are now becoming more widely used for the treatment of congestive heart failure, particularly when it is severe. Beta blockers slow the heart rate.
• Other drugs:  Antiarrhythmic drugs and blood thinners may also be used.

In some individuals with severely weak pumping function of the heart and severe heart failure, a special pacemaker, called a biventricular pacemaker, may be needed. It makes the contraction of the left and right bottom chambers (ventricles) more efficient. In very specific cases, biventricular pacemakers with defibrillation functions are used.

In severe cases, surgical procedures, which can be implemented to sustain life until a transplant donor becomes available, can help but do not cure the disease. They include:

• Left Ventricular Assist Device (LVAD): Treatment provides mechanical circulatory support.
• Dynamic Cardiomyoplasty: A procedure in which a skeletal-muscle flap, created from a patient's thoracic (chest) muscle, is trained to contract often and "wrapped around" the heart to help it contract.

Advanced, severe heart failure requires heart transplant.

Outlook (Prognosis)

How well a patient does depends on many different things, including the severity of the heart problem, what is causing the cardiomyopathy, and how well the patient responds to treatment.

The disorder is chronic (long-term)and the condition may get worse very quickly.

Possible Complications

• Heart failure
• Arrhythmia

When to Contact a Medical Professional

Go to the emergency room or call the local emergency number (such as 911) if symptoms indicating heart failure develop, or if chest pain is present and not relieved by rest or medication.