Amyloid heart disease, or cardiac amyloidosis, is a condition in which too much of the protein amyloid accumulates in the heart. The deposits of amyloid make it difficult for the heart to function properly. Eventually, amyloid replaces the normal tissue of the heart and can result in heart failure. Amyloid heart disease is a rare condition that can be fatal.
Causes
The exact cause of amyloid heart disease is unknown, but it has been determined that the disease originates in the bone marrow. Bone marrow is responsible for making blood cells and antibodies, which are used by the body to fight off diseases and infections. In a healthy person, once antibodies serve their purpose, they are broken down and disposed of. When the bone marrow produces antibodies that cannot be broken down and these build up in the bloodstream, the condition is known as amyloidosis. From the bloodstream, the antibodies travel to the heart, where they form protein deposits called amyloids.
Symptoms
The primary symptom of amyloid heart disease is shortness of breath during light activity, such as walking up a flight of stairs. Other symptoms include arrhythmia, fatigue, heart palpitations, swelling of legs and feet, excessive nighttime urination and weakness. Clinical symptoms of amyloid heart disease include low blood pressure or blood pressure that drops upon standing and a heart murmur, according to the University of Maryland Medical Center.
Tests
There are a number of tests that can be used to diagnose amyloid heart disease. A chest computed topography, or CT, scan is the primary testing method used. The CT scan uses an X-ray image of the chest to determine whether or not there are amyloid deposits located on the heart. An electrocardiogram may also be obtained to determine if there are abnormal electrical impulses within the heart or with the heartbeat. If amyloid heart disease is suspected, confirmation testing includes a cardiac biopsy. A small tissue sample will be taken from the heart and stained with a special dye that reacts with amyloid, according to Cedars-Sinai Heart Center. The tissue will then be examined under a microscope.
Treatment
Amyloid heart disease is usually treated with a combination of medications and lifestyle changes. Medications include melphalan, which is a drug used for chemotherapy, and dexamethasone, which is a corticosteroid that is used to decrease inflammation, according to Mayo Clinic. Diuretics may also be recommended in order to remove excess fluid. Lifestyle changes include a diet that is low in sodium accompanied by fluid restrictions. Peripheral blood stem cell transplantation may also be used to replace the diseased bone marrow that is producing the malfunctioning antibodies. Severe cases of amyloid heart disease may require a heart transplant.
Complications
If left untreated, amyloid heart disease can cause heart failure. Amyloid will continue to accumulate in the heart and eventually replace healthy tissue. The amyloid deposits also reduce the heart's ability to pump correctly and fill with blood. In turn, the heart will not be able to provide enough blood to the rest of the body, which can result in extreme fatigue and exhaustion.
