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.
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 heart beats (arrhythmias) and faulty heart signals (heart block).
Cardiac amyloidosis is more common in men than in women. The disease is rare in people under age 40.
Some patients may have no symptoms. When present, symptoms may include:
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:
- Chest or abdomen CT scan (considered the "gold standard" to help diagnose this condition)
- Coronary angiography
- Magnetic resonance imaging (MRI)
- Nuclear heart scans (MUGA, RNV)
An ECG may show problems with the heart beat or heart signals.
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.
Your doctor 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 doctor may tell you to weigh yourself every day. A weight gain of 3 or more pounds over 1 - 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:
- 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.
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 patients can now expect to survive and experience a good quality of life for several years after diagnosis.
- Atrial fibrillation or ventricular arrhythmias
- Congestive heart failure
- Fluid buildup in the abdomen (ascites)
- Increased sensitivity to digoxin
- Low blood pressure and dizziness from excessive urination (due to medication)
- Sick sinus syndrome
- Symptomatic cardiac conduction system disease (arrhythmias related to abnormal conduction of impulses through the heart muscle)
Amyloidosis - cardiac; Primary cardiac amyloidosis - AL type; Secondary cardiac amyloidosis - AA type; Stiff heart syndrome; Senile amyloidosis
Hare JM. The dilated, restrictive, and infiltrative cardiomyopathies. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 68.
McKenna W. Diseases of the myocardium and endocardium. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 60.
Update Date 5/13/2014
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.