Transthyretin Amyloid Cardiomyopathy (ATTR-CM)
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Quick Facts
- ATTR-CM is an underdiagnosed and potentially fatal disease of the heart muscle.
- It is more common in people of African descent — affecting 3–4% of all Black Americans.
- Symptoms closely resemble heart failure and are often misdiagnosed.
- Early diagnosis and new treatments can significantly improve outcomes.
What is Transthyretin Amyloid Cardiomyopathy (ATTR-CM)?
Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed and potentially fatal disease of the heart muscle. In ATTR-CM, a protein called transthyretin becomes misshapen and builds up in the heart, nerves, and other organs.
When these protein deposits accumulate in the heart, the walls can become stiff, making it hard for the left ventricle to relax and fill with blood — a condition called cardiomyopathy. As the condition worsens, the heart struggles to pump blood, leading to heart failure.
Amyloidosis is a term that represents several different types of diseases where an abnormal protein called amyloid is produced. These amyloid protein fibers can attach and deposit into organs, tissues, nerves, and other places in the body. When that happens, normal function of the area can be affected. ATTR-CM is the cardiac form of transthyretin amyloidosis.
Types of ATTR-CM
Hereditary ATTR-CM (hATTR-CM)
Hereditary ATTR-CM can run in families. A variant in the transthyretin gene results in amyloid deposits in the heart, nerves, and sometimes the kidneys. Symptoms may start as early as age 30, though most appear later in life. The most common type in the U.S. occurs in 3–4% of all Black Americans. Genetic testing can provide helpful information for creating a treatment plan.
Wild-type ATTR-CM (wATTR-CM)
In wild-type ATTR-CM, there is no variant in the transthyretin gene, and it does not run in families. It mostly affects the heart and can also cause carpal tunnel syndrome and peripheral neuropathy. The disease most often occurs in elderly men.
Risk Factors
Hereditary ATTR-CM
- Family history of ATTR-CM or heart failure
- Older age
- Male sex
- Black race — the most common U.S. variant affects 3–4% of Black Americans
Wild-type ATTR-CM
- Older age
- Male sex
Symptoms
Symptoms of ATTR-CM can vary or be hard to notice. The condition is often misdiagnosed because in early stages it resembles other heart problems. Some people may have no symptoms, while others may progress to end-stage heart failure.
Primary symptoms (similar to heart failure)
- Shortness of breath while resting or with little activity
- Swelling in the lower legs
- Chest congestion
Additional symptoms
- Coughing or wheezing, especially when lying down
- Swelling in the feet, ankles, and legs
- Bloating in the abdomen
- Confusion or trouble thinking
- Increased heart rate or palpitations
ATTR-CM specific symptoms
- Numbness or tingling in the hands and feet (hATTR-CM)
- History of spinal stenosis (wATTR-CM)
- Carpal tunnel syndrome (wATTR-CM)
Possible Complications
Cardiac amyloidosis changes your heart's structure and can disrupt its electrical system. Possible complications include:
- Arrhythmias, including atrial fibrillation (AFib), bradycardia, and ventricular tachycardia
- Bundle branch block
- Cardiorenal syndrome
- Heart failure
- Restrictive cardiomyopathy
- Stroke
Clinical Red Flags
Healthcare providers look for the following red flags that point to cardiac amyloidosis, in addition to heart failure symptoms:
- Atrial fibrillation (AFib)
- Thickness in the wall of the left ventricle
- Conduction system disease
- Elevated cardiac biomarkers
- High levels of protein in urine
- History of carpal tunnel syndrome
- Lumbar spinal stenosis
- Peripheral or autonomic neuropathy
- Prior shoulder surgery
- Hip or knee replacement
How is ATTR-CM Diagnosed?
ATTR-CM may be suspected based on common symptoms and routine cardiac tests such as an electrocardiogram or echocardiogram. Once suspected, more specialized tests are needed to confirm the diagnosis. Because most amyloidosis diseases have different treatments, the correct diagnosis is extremely important.
- Blood and urine tests to check for amyloid proteins and markers of heart function
- Electrocardiogram (EKG) to check the heart's electrical activity
- Echocardiogram with strain to look for thickened heart muscle
- Cardiac MRI to distinguish cardiac amyloidosis from other causes of cardiomyopathy
- Nuclear imaging tests, including amyloid scans, to check for amyloid protein buildup
- Biopsy to check for amyloids in the heart or elsewhere
- Genetic testing to check for genetic changes as the cause of amyloidosis
How Can ATTR-CM Be Treated?
There are promising new treatments available for ATTR-CM. Treatment depends on the type of amyloidosis. In general, there are three main groups of treatments: amyloid-specific medications to slow or stop the production of abnormal proteins, treatments that manage symptoms, and organ transplantation to replace an organ that amyloidosis has damaged.
Currently, there is no cure for cardiac amyloidosis. But early diagnosis and treatment can help limit long-term damage to the heart. Researchers are currently studying other medications that target the underlying causes of cardiac amyloidosis.
Research is advancing rapidly. The FDA has granted Fast Track Designation to new therapies targeting amyloidosis, and clinical trials continue to expand treatment options for patients. Ask your healthcare provider if you can join a clinical trial.
Outlook and Prognosis
How cardiac amyloidosis will affect you depends on many factors, including the type of amyloidosis, your age, how long you had the disease before diagnosis, how quickly you begin treatment, and other health conditions you have.
The outlook is generally worse in light-chain (AL) amyloidosis due to how quickly it progresses. ATTR has a slower — but still significant — course. Regardless of the type, cardiac amyloidosis is the leading cause of death in people with amyloidosis.
In general, the sooner you receive treatment, the better your outlook and life expectancy. With each year that passes, researchers learn more about this disease and how to slow it down.
For Patients & Families
If you or a loved one has been diagnosed with ATTR-CM — or you are concerned about symptoms — these trusted resources can help you understand your condition, find specialized care, and connect with others who share your experience.
Amyloidosis Foundation — Patient Resources
Learn moreMedical InformationCleveland Clinic — Cardiac Amyloidosis Overview
Learn moreSpeak with a NurseTalk to a Heart Nurse — Cleveland Clinic
Learn moreTip for your appointment: Write down your symptoms, how long you have had them, and any family history of heart failure or amyloidosis. Bring this list to your next visit and ask your provider whether ATTR-CM testing is right for you.
Downloadable Resources & Videos
The following fact sheets, guides, podcasts, and videos are provided by trusted cardiovascular and amyloidosis organizations to help patients, caregivers, and healthcare providers learn more about ATTR-CM and hereditary amyloidosis.
Fact Sheets & Guides
Hereditary Amyloidosis: What You Need to Know
Preventive Cardiovascular Nurses Association (PCNA)
A clinical fact sheet that defines hATTR amyloidosis, lists signs and symptoms, describes diagnosis, and provides resources on genetic testing, treatments, and ongoing support. Available in English and Spanish. Reviewed March 2026.
View & DownloadFeatured Video
Video
Full Version-Don't Pass on Your Heart Health. Real Stories. Real Talk. Recognizing ATTR-CM
Watch VideoEducational Videos
Amyloidosis Foundation
ATTR Amyloidosis Explained
A detailed explanation of transthyretin amyloidosis, covering hereditary and wild-type forms, symptoms, and current treatment options.
Watch on YouTube
Amyloidosis Foundation
Cardiac Amyloidosis — What You Need To Know
Dr. Hasan Siddiqi from Vanderbilt Health covers how cardiac amyloidosis is diagnosed and managed, with a focus on ATTR-CM.
Watch on YouTube
Amyloidosis Foundation
Hereditary ATTR Amyloidosis and the Heart
Experts discuss the hereditary form of ATTR amyloidosis, its disproportionate impact on Black Americans, and the importance of genetic counseling.
Watch on YouTube
YouTube
ATTR-CM & Heart Failure: What Patients Need to Know
An educational overview of ATTR-CM and its relationship to heart failure, covering diagnosis, treatment advances, and what patients and families should discuss with their care team.
Watch on YouTubeTalk to Your Healthcare Professional
Awareness of ATTR-CM among healthcare teams is low. It is often misdiagnosed as hypertensive heart failure. By the time symptoms appear and a person is diagnosed, the disease may already be advanced.
If you have heart failure and other unresolved or seemingly unrelated symptoms, talk to your healthcare professional. Starting that conversation could save your life.
- Tell your healthcare professional if you have trouble breathing.
- Ask them to run tests and make a treatment plan based on your diagnosis.
- If treatment does not improve your symptoms, ask about next steps.
- If you have ATTR-CM, genetic testing can help your provider choose the best treatment plan.
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Getting support for you and your caregivers is important for your health. Research shows that seeking support can make it easier to live a longer, healthier life. Reach out to Healthy Heart CPP to connect with community resources.
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