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Cardiac amyloidosis

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

Causes

Amyloidosis is a group of diseases in which clumps of proteins called amyloids build up in body tissues. Over time, these proteins replace normal tissue, leading to failure of the involved organ. There are many forms of amyloidosis.

Cardiac amyloidosis ("stiff heart syndrome") occurs when amyloid deposits take the place of normal heart muscle. It is the most typical type of restrictive cardiomyopathy. Cardiac amyloidosis may affect the way electrical signals move through the heart (conduction system). This can lead to abnormal heartbeats (arrhythmias) and faulty heart signals (heart block).

The condition can be inherited. This is called familial cardiac amyloidosis. It can also develop as the result of another disease such as a type of bone and blood cancer, or as the result of another medical problem causing inflammation. Cardiac amyloidosis is more common in men than in women. The disease is rare in people under age 40.

Symptoms

Some people may have no symptoms. When present, symptoms may include:

  • Excessive urination at night
  • Fatigue, reduced exercise ability
  • Palpitations (sensation of feeling heartbeat)
  • Shortness of breath with activity
  • Swelling of the abdomen, legs, ankles, or other part of the body
  • Trouble breathing while lying down

Exams and Tests

The signs of cardiac amyloidosis can be related to a number of different conditions. This can make the problem hard to diagnose.

Signs may include:

  • Abnormal sounds in the lung (lung crackles) or a heart murmur
  • Blood pressure that is low or drops when you stand up
  • Enlarged neck veins
  • Swollen liver

The following tests may be done:

An ECG may show problems with the heartbeat or heart signals. It may also show low signals (called “low voltage”).

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

When a small piece of heart muscle tissue is needed for examination, a heart biopsy can be performed.  A catheter is carefully threaded into an artery or vein to gain access into the heart. A bioptome (catheter with jaws in its tip) is then introduced. Once the bioptome is in place, three to five small pieces of tissue from the heart muscle are removed.  The test is performed routinely after heart transplantation to detect potential rejection. It may also be performed when cardiomyopathy, myocarditis, cardiac amyloidosis, or other disorders are suspected.

Treatment

Your health care provider may tell you to make changes to your diet, including limiting salt and fluids.

You may need to take water pills (diuretics) to help your body get rid of excess fluid. The provider may tell you to weigh yourself every day. A weight gain of 3 or more pounds (1 kilogram or more) over 1 to 2 days can mean there is too much fluid in the body.

Medicines including digoxin, calcium-channel blockers, and beta-blockers may be used in people with atrial fibrillation. However, the drugs must be used with caution, and the dosage must be carefully monitored. People with cardiac amyloidosis may be extra sensitive to side effects of these drugs.

Other treatments may include:

  • Chemotherapy
  • Implantable cardioverter-defibrillator (AICD)
  • Pacemaker, if there are problems with heart signals
  • Prednisone, an anti-inflammatory medicine

A heart transplant may be considered for people with some types of amyloidosis who have very poor heart function. People with hereditary amyloidosis may need a liver transplant.

Outlook (Prognosis)

In the past, cardiac amyloidosis was thought to be an untreatable and rapidly fatal disease. However, the field is changing rapidly. Different types of amyloidosis can affect the heart in different ways. Some types are more severe than others. Many people can now expect to survive and experience a good quality of life for several years after diagnosis.

Possible Complications

Complications may include:

When to Contact a Medical Professional

Call your provider if you have this disorder and develop new symptoms such as:

  • Dizziness when you change position
  • Excessive weight (fluid) gain
  • Excessive weight loss
  • Fainting spells
  • Severe breathing problems

Alternative Names

Amyloidosis - cardiac; Primary cardiac amyloidosis - AL type; Secondary cardiac amyloidosis - AA type; Stiff heart syndrome; Senile amyloidosis

References

McKenna W, Elliott P. Diseases of the myocardium and endocardium. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 60.

Warnes CA. Pregnancy and heart disease. In: Bonow RO, Mann DL, Zipes DP, Libby P, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 10th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 78.

Review Date 5/5/2016

Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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