Definition:
Cardiac amyloidosis is a disorder caused by deposits of an abnormal protein (amyloid) in the heart tissue, which make it hard for the heart to work properly.
Alternative Names:
Amyloidosis - cardiac; Primary cardiac amyloidosis - AL type; Secondary cardiac amyloidosis - AA type; Stiff heart syndrome; Senile amyloidosis
Causes, incidence, and risk factors:
Amyloidosis refers to a family of diseases in which there is a buildup of clumps of proteins called amyloids in body tissues and organs. These proteins slowly replace normal tissue, leading to failure of the involved organ. There are many forms of amyloidosis. Cardiac amyloidosis usually occurs during primary amyloidosis (AL type amyloidosis). Primary amyloidosis is often seen in people with multiple myeloma cancer. 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 arrhythmias and conduction disturbances (heart block). Secondary amyloidosis (AA type) rarely affects the heart. However, a form of secondary amyloidosis called senile amyloidosis involves the heart and blood vessels. Senile amyloidosis is caused by overproduction of a different protein. The condition 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.
References:
Hare JM. The Dilated, Restrictive, and Infiltrative Cardiomyopathies. In: Libby P, Bonow RO, Mann DL, Zipes DP. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 64.
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