Transthyretin amyloid cardiomyopathy (ATTR-CM) is a rare heart condition that occurs when transthyretin, a protein in the body, changes shape and clumps together. The clumps can make the heart stiff and weak over time, leading to symptoms like shortness of breath, swelling, and fatigue.
There are several steps and tests doctors can use to diagnose ATTR-CM.
ATTR-CM is usually first suspected based on symptoms as well as results from routine heart tests, like an electrocardiogram (EKG) or echocardiogram.
- EKG: The quick, noninvasive test records the heart’s electrical activity using small patches placed on the skin.
- Echocardiogram: Also called an echo, the test uses sound waves to create moving pictures of your heart. It provides information on the heart’s size, shape, and how well it pumps.
If ATTR-CM is suspected based on these findings, more specific tests can confirm the diagnosis.
Specialized imaging studies of the heart can be used to diagnose ATTR-CM. Most often, the test would be one or both of the following:
- Cardiac magnetic resonance imaging (MRI): The noninvasive imaging test uses a strong magnet and radio waves to create detailed pictures of your heart. It shows the heart’s structure; how well it pumps; and whether there is scarring, thickening, or other signs of heart disease. This test may be used when symptoms or earlier tests suggest a heart issue or when they want a closer look at the heart muscle, valves, or blood flow.
- PYP scan: PYP stands for pyrophosphate, a substance used in the test. A small amount of PYP is injected into your vein. The substance will collect anywhere ATTR is and show up in images that machines take of your heart’s structure.
Genetic testing can be used to diagnose hereditary ATTR-CM.
What it does: Genetic testing looks for changes, or variants, in a gene. Specifically, the test looks for a transthyretin (TTR) gene variant linked to hereditary ATTR-CM. The variant can cause transthyretin protein to build up in the heart, nerves, and other organs, causing ATTR-CM.
Results: A positive result means the gene change is present. A negative result means no disease-causing variant was found.
What to expect: Genetic testing for ATTR-CM is minimally invasive, using a small sample of blood or saliva. Results are typically available in a few weeks.
After the test: You may be referred to a genetic counselor who can explain what the results mean and how they may affect your health. They can also help you talk with family members about any genetic findings and provide written information to share with relatives who may want to be tested.
Tissue biopsy may be used to assist with diagnosing ATTR-CM. A tissue biopsy is a test where a small sample of heart tissue is taken and viewed under a microscope to check for amyloid protein buildup.
The best place to start when it comes to diagnosing ATTR-CM is with your primary care provider or a cardiologist. They can review your symptoms, order initial heart tests, and refer you to specialists who are familiar with diagnosing amyloidosis. If hereditary ATTR-CM is suspected, they may also connect you with a genetic counselor who can help guide testing for you and your family.
