Cardiac Amyloidosis

Cardiac amyloidosis is a serious condition where abnormal proteins called amyloid build up in the heart, making it stiff and unable to pump blood effectively. This can lead to heart failure and other complications. Early diagnosis and treatment are crucial to manage symptoms and slow the disease's progression, improving the overall outlook for affected individuals.

What is Cardiac Amyloidosis?

Cardiac amyloidosis is a serious disease where abnormal protein deposits, called amyloid, build up in the heart muscle. This buildup makes the heart stiff and prevents it from pumping blood properly, leading to symptoms like shortness of breath and swelling. It can eventually cause heart failure if not managed.

Amyloid is a protein that the body cannot break down correctly. Instead, it folds into an abnormal shape and collects in various organs. When these deposits accumulate in the heart, it's called cardiac amyloidosis. The heart muscle becomes thick and stiff due to the amyloid deposits. This stiffness makes it harder for the heart to fill with blood between beats and to pump blood out to the body. Imagine a balloon that has lost its stretchiness; it can't inflate or deflate well. This condition interferes with the heart's normal function, including its electrical signals. Over time, it can lead to serious problems like heart failure, where the heart can no longer pump enough blood to meet the body's needs.

Symptoms

Symptoms of cardiac amyloidosis often include shortness of breath, especially with activity or when lying flat, and swelling in the legs, ankles, or feet. People may also experience extreme tiredness (fatigue), irregular heartbeats, chest pain, or dizziness. These signs develop as the heart struggles to pump blood effectively.

Many symptoms are related to the heart's reduced ability to pump blood. Shortness of breath (dyspnea) is common, particularly during physical activity or when lying down, because fluid can build up in the lungs. Swelling (edema) in the legs, ankles, and feet occurs when the heart cannot effectively circulate blood, causing fluid to pool in the lower extremities. Some people may also notice swelling in their abdomen. Other common symptoms include feeling very tired (fatigue), lightheadedness or fainting (syncope), and irregular heartbeats (arrhythmias). Some individuals might experience chest pain (angina) or unexplained weight loss. It's important to note that these symptoms can also be signs of other heart conditions.

Causes & risk factors

Cardiac amyloidosis is caused by the body producing abnormal amyloid proteins that deposit in the heart. It is not contagious. The main types are AL amyloidosis, linked to blood cell disorders, and ATTR amyloidosis, which can be hereditary or age-related. Risk factors include older age, being male, and certain genetic backgrounds.

The condition is caused by the buildup of amyloid proteins, not by an infection or something you can catch. There are different types of amyloid proteins that can affect the heart. The two most common types are AL amyloidosis and ATTR amyloidosis. AL amyloidosis (light chain amyloidosis) is the most common form of amyloidosis. It occurs when certain white blood cells in the bone marrow produce abnormal antibody fragments (light chains) that form amyloid. This type is often associated with blood cell disorders like multiple myeloma. ATTR amyloidosis (transthyretin amyloidosis) involves a protein called transthyretin. This type can be hereditary, meaning it's passed down through families due to a genetic mutation. It can also be wild-type, which is age-related and usually affects men over 70, even without a genetic mutation. Risk factors include being older, male, and of African American descent for the hereditary ATTR type.

How it's diagnosed

Diagnosing cardiac amyloidosis involves a combination of tests to identify amyloid deposits and assess heart function. Doctors typically use imaging tests like echocardiograms and cardiac MRI, along with blood and urine tests to look for abnormal proteins. A biopsy, often of the heart or another tissue, is usually needed to confirm the presence of amyloid.

Your doctor will start with a physical exam and review your medical history and symptoms. Blood and urine tests are often performed to check for abnormal proteins that might indicate amyloidosis. Imaging tests are crucial. An echocardiogram uses sound waves to create images of your heart, showing if the walls are thickened or stiff. A cardiac MRI (magnetic resonance imaging) provides detailed pictures of the heart's structure and can help detect amyloid deposits. Nuclear imaging, such as a bone scan, can specifically identify ATTR amyloidosis in the heart. To confirm the diagnosis, a biopsy is usually necessary. This involves taking a small tissue sample, often from the heart itself, a fat pad in the abdomen, or bone marrow. The sample is then examined under a microscope to confirm the presence of amyloid proteins. Genetic testing may also be done if hereditary ATTR amyloidosis is suspected.

Treatment options

While there is no cure for cardiac amyloidosis, treatments focus on managing symptoms and slowing the buildup of amyloid protein. Treatment plans vary based on the type of amyloidosis. Options include chemotherapy for AL amyloidosis, specific medications to stabilize or reduce ATTR protein, and general heart medications to control symptoms like swelling and irregular heartbeats.

Treatment aims to reduce the production of abnormal proteins and manage the symptoms caused by heart damage. For AL amyloidosis, chemotherapy is often used to target the abnormal cells producing the amyloid protein. In some cases, a stem cell transplant may be an option. For ATTR amyloidosis, specific medications are available. Some drugs, called stabilizers (like tafamidis), work by preventing the transthyretin protein from misfolding. Other medications, known as silencers (like patisiran or inotersen), reduce the amount of transthyretin protein the body produces. Regardless of the type, general heart medications are used to manage symptoms. Diuretics help reduce fluid buildup and swelling. Blood thinners (anticoagulants) may be prescribed to prevent blood clots. For irregular heartbeats, pacemakers or implantable cardioverter-defibrillators (ICDs) might be considered. In very severe, rare cases, a heart transplant might be an option, but this is uncommon.

Recovery & outlook

Cardiac amyloidosis is a serious condition, but the outlook has improved significantly with earlier diagnosis and new treatments. Recovery involves ongoing management of symptoms and the underlying protein buildup. The specific type of amyloidosis and how early it is diagnosed and treated greatly influence a person's long-term prognosis.

The outlook for people with cardiac amyloidosis varies widely depending on the type of amyloid protein involved, how advanced the disease is at diagnosis, and how well a person responds to treatment. Historically, the prognosis was poor, but advancements in diagnostic tools and therapies have led to better outcomes. Early diagnosis is crucial because starting treatment before significant heart damage occurs can slow the disease's progression and improve heart function. Regular follow-up appointments and adherence to the treatment plan are vital for managing the condition effectively. While there isn't a cure, treatments can help control symptoms, improve quality of life, and extend survival. Research continues to explore new and more effective therapies, offering hope for future improvements in the management of this complex disease.

When to see a doctor

You should see a doctor if you experience new or worsening symptoms that could indicate cardiac amyloidosis, such as increasing shortness of breath, unexplained swelling in your legs or feet, or persistent fatigue. Seek immediate medical attention if you have severe chest pain, sudden dizziness, or fainting, as these could be signs of a serious heart problem.

It's important to consult your doctor if you notice any persistent or new symptoms that might suggest a heart problem. These include feeling unusually tired, having difficulty breathing, especially when active or lying down, or experiencing swelling in your ankles, legs, or abdomen. If you have a family history of amyloidosis or have been diagnosed with a condition known to cause amyloidosis, such as multiple myeloma, you should discuss any new symptoms with your doctor promptly. Seek emergency medical care immediately if you experience severe chest pain, sudden and extreme shortness of breath, rapid or irregular heartbeats accompanied by dizziness, or if you faint. These symptoms could indicate a life-threatening cardiac event.

Frequently asked questions

Is cardiac amyloidosis a genetic disease?

Only one type of cardiac amyloidosis, hereditary ATTR amyloidosis, is genetic. This means it's caused by a gene mutation passed down through families. Other types, like AL amyloidosis and wild-type ATTR amyloidosis, are not inherited.

Can cardiac amyloidosis be cured?

Currently, there is no cure for cardiac amyloidosis. However, treatments are available to manage symptoms, slow the buildup of amyloid protein, and improve heart function. Early diagnosis and consistent treatment can significantly improve a person's quality of life and outlook.

How common is cardiac amyloidosis?

Cardiac amyloidosis is considered a rare disease. The exact prevalence can be hard to determine because it is often underdiagnosed or misdiagnosed due to its varied symptoms and similarity to other heart conditions. Wild-type ATTR amyloidosis is becoming more recognized, especially in older men.

What is the difference between AL and ATTR cardiac amyloidosis?

AL (light chain) cardiac amyloidosis is caused by abnormal antibody fragments produced by bone marrow cells, often linked to blood disorders. ATTR (transthyretin) cardiac amyloidosis involves the transthyretin protein, which can be hereditary (genetic) or wild-type (age-related). The type of protein determines the specific treatment approach.

Can lifestyle changes help manage cardiac amyloidosis?

While lifestyle changes cannot cure cardiac amyloidosis or stop amyloid buildup, they can help manage symptoms and support overall heart health. This includes following a heart-healthy diet, limiting salt intake to reduce fluid retention, staying physically active as advised by your doctor, and avoiding smoking and excessive alcohol.

What kind of doctor treats cardiac amyloidosis?

Cardiac amyloidosis is typically managed by a team of specialists. This often includes a cardiologist (heart doctor), a hematologist (blood disorder specialist, especially for AL type), and sometimes a neurologist (for nerve involvement) or a nephrologist (kidney specialist). An amyloidosis specialist at a specialized center may also be involved.

Sources

• MedlinePlus — Cardiac Amyloidosis
• Mayo Clinic — Cardiac Amyloidosis
• Cochrane Library — Cardiac Amyloidosis