Hypertrophic cardiomyopathy Health Article

Definition

Hypertrophic cardiomyopathy (HCM) is a form of cardiomyopathy, a condition in which the heart muscle to become thick. The thickening makes it harder for the heart to work.

Alternative Names

Cardiomyopathy - hypertrophic (HCM); IHSS; Idiopathic hypertrophic subaortic stenosis; Asymmetric septal hypertrophy; ASH; HOCM; Hypertrophic obstructive cardiomyopathy

Causes, incidence, and risk factors

Hypertrophic cardiomyopathy is often asymmetrical, meaning one part of the heart is thicker than the other parts. The condition is usually passed down through families (inherited). It is believed to be a result of several problems (defects) with the genes that control heart muscle growth.

The thickened heart muscle makes it harder for blood to leave the heart. The heart must work harder to pump blood. The size of the heart chamber (ventricular chamber) is also smaller than usual.

The thickening of the heart muscle may also make it harder for the heart valves to work. Heart valves help control the direction of blood flow.

Younger people are likely to have a more severe form of hypertrophic cardiomyopathy. However, the condition is seen in people of all ages.

Symptoms

• Chest pain
• Fainting, especially during exercise
• Light-headedness, especially after activity or exercise
• Dizziness
• Sensation of feeling heart beat (palpitations)
• Shortness of breath
• Heart failure (in some patients)
• Hypertension

Additional symptoms that may occur are:

• Fatigue, reduced activity tolerance
• Shortness of breath when lying down

Some patients have no symptoms, and may not even realize they have the condition until it is found during a routine medical exam.

Unfortunately, the first symptom of hypertrophic cardiomyopathy among many young patients is sudden collapse and possible death. This is caused by very abnormal heart rhythms (arrhythmias). Hypertrophic cardiomyopathy is a major cause of death in young athletes who seem completely healthy but die during heavy exercise.

Signs and tests

The health care provider will perform a physical exam and listen to the heart and lungs with a stethoscope. Listening with a stethoscope may reveal abnormal heart sounds or a murmur, which may change with different body positions. The pulse in your arms and neck will be checked. The doctor may feel an abnormal heart beat in the chest.

Most frequently, however, nothing is found during a physical exam, and the exam is considered normal.

Tests used to diagnose heart muscle thickness, problems with blood flow, or leaky heart valves (mitral valve regurgitation) may include:

• Echocardiography (the most common test) with Doppler ultrasound
• Transesophageal echocardiogram (TEE)
• Chest x-ray
• ECG
• 24-hour Holter monitor (heart monitor)
• Cardiac catheterization
• MRI of the heart

Blood tests may be done to rule out other possible diseases.

If you are diagnosed with hypertrophic cardiomyopathy, your health care provider may recommend that your close blood relatives (family members) be screened for the condition.

Treatment

The goal of treatment is to control symptoms and prevent complications. Some patients may need to stay in the hospital until the condition is under control (stabilized).

Medicines may be needed to help the heart contract and relax correctly. Drugs include beta-blockers and calcium channel blockers. These medicines reduce chest pain and pain during exercise. Sometimes, a pacemaker is used.

When blood flow out of the heart is severely blocked, an operation called myotomy-myectomy is done. This procedure cuts and removes the thickened part of the heart. Patients who have this procedure often show significant improvement.

If the heart's mitral valve is leaking, surgery may be done to repair or replace the valve.

Some people with arrhythmias may need anti-arrhythmic medications. If the arrhythmia is atrial fibrillation, blood thinners will also be used to reduce the risk of blood clots.

In some cases, a patient may be given an injection of alcohol into the arteries that feed the thickened part of the heart. This procedure is called alcohol septal ablation. It helps decrease the blockage and helps blood flow out of the heart.

An implantable-cardioverter defibrillator (ICD) may be needed to prevent sudden death. ICDs are used in high-risk patients. High risks include severe heart muscle thickness, life-threatening heart rhythms, a history of fainting, or a family history of sudden cardiac death.