Amyloidosis - cardiac

Definition

Cardiac amyloidosis is a disorder caused by deposits of an abnormal protein in the heart tissue, which make it hard for the heart to work properly.

Alternative Names

Causes

Amyloidosis is the accumulation of clumps of proteins called amyloids in body tissues and organs. The proteins slowly replace normal tissue. There are many forms of amyloidosis.

Cardiac amyloidosis usually occurs during primary amyloidosis, also called AL type amyloidosis. Primary amyloidosis is usually seen in persons with multiple myeloma, a type of cancer.

Cardiac amyloidosis, also called "stiff heart syndrome," occurs when amyloid deposits take the place of normal heart muscle. It is the most typical type of restrictive cardiomyopathy. Patients with cardiac amyloidosis may have changes in the way electrical signals move through the heart. This is called a conduction disturbance.

Secondary amyloidosis, also called AA type, rarely affects the heart. However, a subtype of secondary amyloidosis called senile amyloidosis involves the heart and blood vessels. Senile amyloidosis is caused by overproduction of a protein different from both the AA and AL types. Senile cardiac amyloidosis is becoming more common as the average age of the population increases.

Cardiac amyloidosis is more common in men than in women. The disease is rare in people under age 40.

Symptoms

• Palpitations (sensation of feeling heart beat)
• Swelling of legs, ankles, or other part of the body (See: abdominal swelling)
• Excessive urination at night
• Fatigue, reduced activity tolerance
• Shortness of breath with activity
• Trouble breathing while lying down

Some patients may have no symptoms.

Exams and Tests

It can be difficult to diagnose cardiac amyloidosis, because the signs are not specific, which means they can be related to a number of different conditions.

The health care provider may hear abnormal sounds in the lung (lung crackles) or a heart murmur when listening to your heart and chest with a stethoscope. This may suggest fluid in the lungs, enlargement of the heart

The following tests may be used to help diagnose cardiac amyloidosis:

• Echocardiogram
• Chest x-ray
• Chest or abdomen CT scan
• Coronary angiography
• Nuclear heart scans (MUGA, RNV)
• Magnetic resonance imaging (MRI)

An ECG may show problems with the heart beat or heart signals (conduction disturbance).

A cardiac biopsy is used to confirm the diagnosis. A biopsy of another area, such as the abdomen, kidney, or bone marrow, is frequently done to confirm the diagnosis of amyloidosis.

Treatment

You can continue to exercise as long as feel like you can.

Your doctor may tell you to make changes to your diet. This may include salt and fluid restrictions.

Diuretics (water pills) may be given to help the body remove excess fluid. The doctor may tell you to weigh yourself everyday. A weight gain of three or more pounds over 1 or 2 days can mean there is too much fluid in the body.

Digoxin, calcium channel blockers, and beta blockers may be used with caution in patients with atrial fibrillation. However, the dosage must be carefully monitored, since patients with cardiac amyloidosis may be unusually sensitive to any side effects.

Other treatments may include:

• Chemotherapy
• Prednisone, an anti-inflammatory medicine
• Pacemaker, if there are problems with heart signals

A heart transplant may be considered for some patients with very poor heart function. However, it is not done in those with AL type amyloidosis, since the disease weakens many other organs. A liver transplant is needed in those with hereditary amyloidosis.

Outlook (Prognosis)

Cardiac amyloidosis is a long-term (chronic) condition that slowly gets worse. On average, persons with cardiac amyloidosis live less than 1 year.

Possible Complications

• Congestive heart failure
• Atrial fibrillation or ventricular arrhythmias
• Sick sinus syndrome (occasionally)
• Symptomatic cardiac conduction system disease (arrhythmias related to abnormal conduction of impulses through the heart muscle)
• Low blood pressure and dizziness from excessive urination (from medication)
• Increased sensitivity to digoxin with the potential for digoxin toxicity and related arrhythmias
• Ascites (fluid accumulation in the abdomen)

When to Contact a Medical Professional

Call your health care provider if you have this disorder and new symptoms develop, particularly:

• Postural dizziness
• Fainting spells
• Excessive weight (fluid) gain
• Excessive weight loss
• Severe difficulty breathing

Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed. St. Louis, Mo: WB Saunders; 2005:1683-1685.

Arora S, Arora A, Makkar RP, Monga A. Stiff heart syndrome. CMAJ. 2003 Jun 24;168(13):1690-1.

Kholova I, Kautzner J. Current treatment in cardiac amyloidosis. Curr Treat Options Cardiovasc Med. 2006 Dec;8(6):468-73.