Key takeaways

  • Hereditary transthyretin amyloid cardiomyopathy (hATTR-CM) is an inherited heart condition in which protein buildup in the heart muscle causes it to stiffen and thicken, often leading to heart failure.
  • Early symptoms, which may mimic those of heart failure, include shortness of breath, chest congestion, and reduced exercise ability. As the condition progresses, you may experience swelling in your feet or ankles, an irregular heartbeat, fatigue, and coughing.
  • This condition is often misdiagnosed because of a lack of awareness among healthcare professionals. If you’re living with heart failure and experience new symptoms like trouble breathing, talk with a healthcare professional and be persistent about testing.

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a rare, potentially life threatening heart disease that involves a buildup of proteins in the wall of the myocardium (the heart muscle). As this buildup progresses, it can cause or worsen heart failure.

The condition may occur as a result of a gene variant that gets passed from parent to child. This form is called hereditary ATTR-CM (hATTR-CM). It’s inherited in an autosomal dominant pattern, meaning you can inherit the condition from one parent who carries the gene variant.

Symptoms of hATTR-CM may begin by 30 years of age.

In this article, we’ll discuss the symptoms of hATTR-CM, how the condition progression, and how it differs from other heart conditions.

In the early stages of hATTR-CM, you may not notice any symptoms. If you do, they may be mild or mimic those of other conditions.

Common early symptoms are similar to those of heart failure and include:

  • shortness of breath
  • chest congestion
  • reduced ability to exercise

These symptoms can occur because the buildup of protein in the heart causes the heart muscle to stiffen and thicken, hindering its ability to pump blood efficiently.

hATTR-CM may cause a range of heart-related symptoms, including irregular heartbeat and additional symptoms of congestive heart failure.

The most common form of arrhythmia people experience is atrial fibrillation. Up to 60% of people have atrial fibrillation when they receive a diagnosis of ATTR-CM. You may also notice heart palpitations (a feeling as if your heart pounding or fluttering).

The condition can also affect electrical activity in your heart, leading to lightheadedness and possibly causing you to feel like you’re about to pass out.

As noted above, the symptoms of hATTR-CM mimic those of heart failure. In addition to shortness of breath and edema (swelling), you may experience fatigue and increased heart rate.

ATTR-CM can cause a range of neurological and skeletal symptoms due to its effects on the peripheral and autonomic nervous systems. However, these effects are more common in wild-type transthyretin amyloid cardiomyopathy (wATTR-CM) than in the hereditary type (hATTR-CM).

Wild-type ATTR-CM occurs as a natural part of aging and is unrelated to the genetic variant found in hATTR-CM.

Neurological and skeletal symptoms linked to ATTR-CM include:

  • carpal tunnel syndrome, often affecting both wrists
  • lumbar spinal stenosis (narrowing of the space around your spinal cord)
  • tendon pain

hATTR-CM may also cause confusion, difficulty thinking, or numbness in your hands or feet.

As hATTR-CM progresses, you may experience a range of other symptoms, which typically accompany the shortness of breath characteristic of the condition.

Heart failure can lead to swelling, often in the feet or ankles. You might also develop a cough or experience wheezing, particularly when lying down.

Damage to your autonomic nervous system can affect multiple systems in your body, including your digestive system. You may experience abdominal bloating.

The onset of ATTR-CM can vary. The hereditary form of the condition may develop as early as 30 years of age.

hATTR-CM is a progressive condition, meaning the symptoms become more intense over time. As the protein deposits build up in your heart tissue, your heart has a more difficult time pumping blood.

In the early stages of the condition, you may notice only mild symptoms or none at all. With hATTR-CM, you may not notice symptoms until the condition has progressed.

The first symptoms to appear are typically shortness of breath, swelling in your feet and ankles, and chest congestion. Later symptoms could include coughing or wheezing, bloating, difficulty thinking, and atrial fibrillation (a type of irregular heart rhythm).

Without treatment, this condition can be fatal. Early detection and treatment are important.

According to the American Heart Association (AHA), hATTR-CM is often misdiagnosed due to a lack of awareness among healthcare professionals. Many people don’t receive a diagnosis until the condition has progressed significantly.

If you’re living with heart failure and you experience additional symptoms, such as trouble breathing, it’s best to speak with a healthcare professional. The AHA recommends being persistent in your interactions with your medical team.

Push for testing that reveals the underlying cause of your new symptoms. If treatment does not reduce your symptoms, follow up with your doctor until you find relief.

In the early stages of the hATTR-CM, the condition may be confused for other diseases of the heart, such as heart failure related to high blood pressure and hypertrophic cardiomyopathy (enlargement and thickening of the heart).

However, unlike those diseases, hATTR-CM can cause a variety of neurological, skeletal, and gastrointestinal symptoms in addition to typical heart-related symptoms.

Hereditary transthyretin amyloid cardiomyopathy (hATTR-CM) is an inherited form of ATTR-CM that involves a buildup of proteins within the wall of the heart. Over time, this condition makes the heart’s walls stiff and thick and reduces the heart’s ability to pump blood.

The early symptoms of hATTR-CM, which are similar to those of heart failure, include shortness of breath, chest congestion, and swelling in your feet and ankles.

As hATTR-CM progresses, it may cause other symptoms, such as coughing, bloating, nerve pain, and irregular heart rhythms.

ATTR-CM is often misdiagnosed. Without treatment, it can cause heart failure and may even be fatal. If you have any symptoms of hATTR-CM, consult a healthcare professional to discuss your concerns.