ENLmedical.com: Conditions And Concerns: Medical Encyclopedia: Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy

Causes and Risks:
The heart enlargement of hypertrophic cardiomyopathy characteristically is asymmetrical, affecting only one side of the heart. It may interfere with the functioning of the heart by narrowing the outflow of the ventricle and the size of the ventricular chamber, and by reducing the ability of the valves to function properly. The enlargement may directly obstruct the flow of blood.

The obstruction is worsened by situations which increase contraction of the heart (examples include stress , stimulation of the sympathetic nervous system, or medications such as digoxin) or situations which decrease return of blood to the heart (for example, dehydration or excessive use of diuretics).

Two forms of the disease occur:

1. IHSS (idiopathic hypertrophic subaortic stenosis): an idiopathic (no known cause) early form of the disease that occurs before the age of 40 and may occur before the age of 10; usually inherited with autosomal dominant transmission. The incidence is about 1 out of 10,000 people.
2. An acquired form that occurs in elderly people with a history of high blood pressure (hypertensive hypertrophic cardiomyopathy).

Prevention:
Identify, by family history, which people are at high risk for the genetic form of the disease. Treat known hypertension .

Symptoms:

shortness of breath ( dyspnea )
chest pain
fainting ( syncope ), especially after activity
lightheadedness , especially after activity
dizziness
sensation of feeling heart beat ( palpitations )

Additional symptoms that may occur

swelling of legs , ankles, or other portion of the body
abdominal swelling or enlargement
decreased amount of urine
need to urinate at night
fatigue , reduced activity tolerance
changes in mental status
- decreased alertness
- difficulty concentrating
cough
loss of appetite

Signs and Tests:
Listening with a stethoscope may reveal abnormal heart sounds . Examining the chest by touching and tapping ( palpation and percussion ) may indicate enlargement of the heart or "double" heartbeat (bifid impulse).

Left ventricular enlargement with normal or increased contractility, and obstruction of blood flow may be shown on:

echocardiography (most common test)
Doppler ultrasound
A coronary angiography may be needed to confirm the diagnosis.
A chest x-ray may or may not show changes.
An ECG may indicate left ventricle enlargement, arrhythmias , MI , and/or ischemic changes.
A heart biopsy may be helpful to distinguish hypertrophic cardiomyopathy from other diseases.

Lab tests are not specifically diagnostic for hypertrophic cardiomyopathy, but tests may be used to rule out other suspected diseases.

Treatment:
Treatment is aimed at control of symptoms. Hospitalization may be required until the condition is stabilized.

Medications include beta-blockers. Calcium channel blockers such as verapamil may be added. Antiarrhythmics may be used to prevent lethal arrhythmias .

Surgical removal of part of the enlarged tissue may be helpful in severe cases.

Prognosis:
The outcome varies. Some affected individuals remain without symptoms for many years and have a normal life span. Sudden death may occur at any time (hypertrophic cardiomyopathy is the most frequent cause of sudden death in athletes). Some may deteriorate gradually or rapidly. There may be progression into dilated cardiomyopathy .

Complications:

congestive heart failure
cardiac arrhythmias , including lethal arrhythmias
dilated cardiomyopathy

Call Your Healthcare Provider:
Call for an appointment with your health care provider if:

symptoms indicate hypertrophic cardiomyopathy may be present.
chest pain , palpitations , faintness , or other new or unexplained symptoms develop.

This is a cross-sectional view of the interior of the heart. The valves, chambers, and associated vessels are labeled.