Cardiac amyloidosis is a relatively rare entity characterized by infiltration of myocardial tissue by amyloid. This results from the misfolding of protein structural components. Amyloid deposition disrupts the normal structure and function of the heart.

There are several types of amyloidosis, including:

-AL amyloidosis (light chain amyloidosis): This is associated with abnormal deposition of immunoglobulin light chains, which are produced by plasma cells in the bone marrow. AL amyloidosis is essentially a hematological malignancy and can affect many organs.

-ATTR amyloidosis (transthyretin amyloidosis): ATTR amyloidosis results from misfolding of the transthyretin protein. It can be hereditary (hereditary ATTR) or acquired (wild type ATTR).

Heart attack is common in both forms.

Light chain amyloidosis

Light chain amyloidosis occurs when certain blood cells in the body begin to multiply and produce too many light chain proteins that begin to accumulate in tissues where they do not belong, such as the kidneys, liver, heart, and gastrointestinal tract. A common cause of this type of cardiac amyloidosis is the diagnosis of certain blood cancers, such as multiple myeloma. Light chain amyloidosis is quite uncommon, but if you develop the condition, it can be very serious. People who develop this type are usually over the age of 40. However, the majority of cases of light chain amyloidosis occur in people age 60 and older. In general, the condition affects men more often than women.

Transthyretin amyloidosis

Transthyretin amyloidosis occurs when the protein transthyretin (also known as proalbumin) builds up in the heart. The liver makes the protein transthyretin, and this protein normally helps transport hormones (such as thyroid hormone) into the blood. But, if you have a mutation in this type of protein, transthyretin can fold abnormally and accumulate throughout the body, which can cause symptoms.

Amyloid buildup can affect the heart's ability to pump blood to the rest of the body. When this function is reduced, heart failure can occur and cause symptoms such as shortness of breath on exertion or at rest, easy fatigue, lower limb swelling, arrhythmias, cough.

In other cases, excess amyloid proteins can disrupt the heart's normal electrical system, which is responsible for making the heartbeat. When this happens, you may be at a higher risk of developing an arrhythmia.

The diagnosis of cardiac amyloidosis typically involves a combination of tests, including echocardiography, cardiac magnetic resonance imaging, and scintigraphy, and rarely, a biopsy of the myocardium may be necessary. However, definitive diagnosis of cardiac amyloidosis and determination of the specific type require serum and urine protein electrophoresis and determination of κ and λ chains in serum and urine. These tests can help detect the presence of abnormal proteins in the blood and urine, which may be indicative of AL amyloidosis.

In addition to suspected hereditary (hATTR) cardiac amyloidosis, genetic testing can identify specific gene mutations and establish the diagnosis. As an adjunct to heart failure symptoms, the determination of natriuretic peptide (NT-proBNP) is useful.

Management of cardiac amyloidosis mainly involves drug therapy. This generally includes drugs to manage the symptoms of heart failure. AL amyloidosis basically requires chemotherapy to treat the hematological malignancy, while for ATTR amyloidosis, there is a specific treatment. tafamidis can be used to stabilize proteins in patients with ATTR amyloidosis and help further reduce amyloid deposition in the myocardium. Special mention should be made of the prevention and management of arrhythmias.