What Is Cardiac Amyloidosis?

Medically reviewed by Christopher Lee, MD

Cardiac amyloidosis is a condition that occurs when abnormal proteins called "amyloid" build up in your heart. These proteins can develop and grow in the heart tissue, increasing your risk for heart failure and abnormal heart rhythms. Common symptoms of this condition include fatigue, shortness of breath, and swelling in the legs. Your healthcare provider will likely prescribe you medications to treat your symptoms and help lower the risk of complications.

Types and Causes of Cardiac Amyloidosis

There are two main types of cardiac amyloidosis: light chain amyloidosis and transthyretin amyloidosis. The exact type you have will be based on the type of protein that is building up in your heart tissue. Light chain amyloidosis involves extra "light chain" proteins (which are normally made to fight infections in the body). Transthyretin amyloidosis involves a protein that normally is responsible for carrying hormones and certain vitamins in the blood.

Light Chain Amyloidosis

Light chain amyloidosis happens when certain blood cells in your body start to multiply and make too many light chain proteins. A common cause of this type of cardiac amyloidosis is having a diagnosis of certain blood cancers, like multiple myeloma.

Normally, light chain proteins play a role in your body's immune system response and help fight infections. But, when there are too many light chains in your blood, they start to accumulate in tissues where they don't belong—such as in your kidney, liver, heart, and gastrointestinal (GI) tract.

It's worth noting that light chain amyloidosis is pretty uncommon, but if you develop the condition, it can be very serious. People who develop this type are typically over the age of 40. But, the majority of light chain amyloidosis cases occur among people in their 60s or older. Generally, people assigned male at birth experience this condition more often than their female counterparts.

Transthyretin Amyloidosis

Transthyretin amyloidosis happens when the transthyretin protein (also known as prealbumin) builds up in your heart. Your liver produces the transthyretin protein and this protein normally helps carry hormones (like your thyroid hormone) in the blood. But, if you have a mutation in this type of protein, transthyretin can fold abnormally and build up throughout the body, which can cause symptoms to occur.

Symptoms

With cardiac amyloidosis, you may experience symptoms that specifically affect the heart and symptoms in other organs later on as amyloid proteins build up in your body.

Heart Symptoms

There are two main problems that amyloidosis can cause in the heart: heart failure and abnormal heart rhythms (arrhythmias).

The buildup of amyloid can affect your heart's ability to pump blood to the rest of your body. When this function is impaired, heart failure can occur and cause symptoms like:

• Shortness of breath

• Difficulty exercising

• Coughing

• Sudden weight gain

• Fluid buildup and swelling in the feet, ankles, and legs

• Fatigue

In other cases, excess amyloid proteins can interrupt your heart's normal electrical system, which is responsible for generating your heartbeat. When this occurs, you may be at a higher risk of developing an arrhythmia. Some common symptoms of arrhythmias include:

• Heart palpitations

• Fainting

• Dizziness

• An unusually fast or slow heart rate

Other Symptoms

Because many other underlying health conditions can cause heart failure and arrhythmias, it can be hard to tease out when amyloidosis is the root cause of your symptoms. However, your provider may be able to diagnose you with cardiac amyloidosis if they suspect the buildup of proteins is also affecting other parts of your body. This condition can cause one or more of the following symptoms:

• Numbness and tingling in the hands and feet

• Easy bruising

• Discoloration around the eyes

• Macroglossia, or the enlargement of your tongue

• Abdominal pain

• Diarrhea

• Constipation

• Spontaneous rupture of your tendons
  

Diagnosis

Diagnosing cardiac amyloidosis can be difficult since there are many causes of heart failure and arrhythmias. Cardiologists (or, doctors who specialize in the heart) are now recognizing that cardiac amyloidosis is actually much more common than previously thought. If you have any symptoms of this condition, it's important to schedule an appointment with your healthcare provider.

At your appointment, your healthcare provider will ask about your medical history and perform a physical exam. However, they will likely order several other tests to confirm a diagnosis and understand the cause of your symptoms. These exams may include:

• Blood test: Checks the levels of heart biomarkers, kidney function, and electrolytes

• Urine test: Looks for protein buildup in the urine, such as albumin and light chains

• Heart imaging scan: Creates detailed images of your heart's structure via an echocardiogram (heart ultrasound), heart magnetic resonance imaging (MRI), and nuclear imaging such as pyrophosphate scan

• Heart biopsy: Removes and analyzes a portion of your heart tissue to determine if amyloid proteins are present
  

• Bone marrow biopsy: Takes a sample of your bone marrow to look for blood cells that have multiplied or are making too many light chain proteins

• Genetic test: Assesses whether you have mutations in the transthyretin gene

Treatment

If you receive a diagnosis for cardiac amyloidosis, the goals of treatment are to reduce your symptoms, treat the underlying cause of your symptoms, and improve your quality of life. Your exact treatment plan will depend on the severity of your condition.

Treatment for Reducing Symptoms

If your condition is causing heart failure or arrhythmias, your provider will likely recommend treatment to reduce the symptoms of each.

Some treatments for heart failure include:

• Taking diuretics (water pills) to manage fluid buildup

• Limiting your salt intake

• Using medications like ACE inhibitors

• Getting a heart transplant, in very severe cases

To treat arrhythmias, your provider may recommend:

• Using antiarrhythmic drugs

• Getting an ablation procedure to reset the heart's rhythm

• Inserting a pacemaker into your heart
  

• Taking blood thinners to help lower the risk of stroke
  

Treatment for Light Chain Amyloidosis

To treat light chain amyloidosis specifically, your provider may recommend therapies that target the blood cells that are creating too many light chain proteins. These therapies include chemotherapy and a stem cell transplant. Chemotherapy kills off the abnormal cells that are making too much light chain protein. Meanwhile, a stem cell transplant occurs after chemotherapy removes abnormal cells and injects new stem cells as a replacement.

Treatment for Transthyretin Amyloidosis

Until recently, there were no direct treatments for transthyretin amyloidosis. Medications to help manage symptoms were the only option available. But in 2019, the U.S. Food and Drug Administration (FDA) approved Vyndamax (tafamidis) which became the first medication to treat transthyretin amyloidosis.

While Vyndamax won't reverse the abnormal proteins that have already built up in your heart, this medication can prevent more amyloid proteins from accumulating in your heart's tissue. In clinical trials, people taking this medication experienced higher survival rates when compared to people with cardiac amyloidosis who were not taking this medication.

How To Prevent Cardiac Amyloidosis

There aren't any surefire ways to prevent cardiac amyloidosis. However, identifying the symptoms and receiving an early diagnosis can help you get treatment sooner and improve your quality of life. It's a good idea to be proactive if you start experiencing symptoms and see your healthcare provider for proper testing.

Related Conditions

Cardiac amyloidosis has several related conditions. The following blood disorders may increase your risk of developing cardiac amyloidosis:

• Multiple myeloma

• Non-Hodgkin's lymphoma

• Waldenström’s macroglobulinemia

• Chronic lymphocytic leukemia (CLL)

It's also worth noting that having a diagnosis for cardiac amyloidosis can also increase your risk of experiencing other health conditions that may occur due to a buildup of amyloid:

• Carpal tunnel syndrome

• Lumbar spinal stenosis (the narrowing of your spinal cord in the lower back, causing back pain)

• Joint problems that require a joint replacement (such as shoulder, hip, or knee replacement)

Living with Cardiac Amyloidosis

It can be worrisome or overwhelming to receive a diagnosis for cardiac amyloidosis. However, staying in contact with your healthcare team (which may include your primary care provider and cardiologist) can help you get the support and care you need. At your check-up appointments, it's good practice to let your care team know if you notice any change in your symptoms.

Healthcare providers also recommend keeping track of your weight if you have this condition. That's because cardiac amyloidosis can often cause fluid buildup. If you notice that your weight has increased more than two or three pounds in just one day, it could be a sign of extra fluid. Letting your healthcare provider know about your weight changes can help them adjust your treatment plan or prescribe diuretics to help rid your body of excess water.

Cardiac amyloidosis can affect your everyday life, making it hard to perform your daily activities and taking a toll on your emotional well-being. Keeping in touch with your providers is just one way to take care of your health. But, asking your loved ones for support, joining a support group with other people living with this condition, or talking to a mental health professional (such as a psychiatrist or psychologist) can help you live well with the condition and get the care you need.

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