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Cardiac Amyloidosis

Amyloidosis is a group of diseases which are characterized by the build-up of abnormal deposits of amyloid fibrils i

These amyloid fibrils, composed of misfolded proteins, build up in organs throughout the body. Over time, these amyloid deposits may cause affected organs to stop working properly, which can eventually lead to organ failure.iiv

The two most common types of amyloidosis that affect the heart are light chain amyloidosis (AL) and transthyretin amyloid cardiomyopathy (ATTR-CM). Each type of amyloidosis is characterized by the make-up of the amyloid protein that deposits in the body’s organs and tissues.ii

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a presentation of ATTR amyloidosis that primarily affects the heart.  Over time, ATTR-CM causes the heart muscle to become stiff, eventually leading to heart failure.i

Causes and Symptoms of Transthyretin Amyloid Cardiomyopathy (ATTR-CM)

ATTR-CM occurs when transthyretin, a transport protein that naturally circulates in the blood, becomes unstable. The unstable protein misfolds, creating amyloid fibrils that can build up in the heart and other parts of the body. The buildup causes the heart muscle to stiffen over time, eventually leading to heart failure.iiv

ATTR-CM often presents with symptoms of heart failure, such as fatigue, shortness of breath and peripheral edema, but may also include other symptoms related to buildup of amyloid fibrils throughout the body. Often, the disease is diagnosed only after symptoms have become severe. ii,iii, v, vi

Receiving a correct diagnosis of ATTR-CM has historically been difficult because disease awareness is low, even among healthcare providers.viii In fact, people living with ATTR-CM face delays in receiving the correct diagnosis, often waiting years after symptoms present.v

Education, awareness and treatment are critical to improving the diagnosis and care of people affected by ATTR-CM.

Two Sub-types of Transthyretin Amyloid Cardiomyopathy (ATTR-CM)

There are two forms of ATTR-CM, hereditary or variant (hATTR) and wild-type (wtATTR).iv

The hereditary form of the disease is caused by a mutation in the transthyretin gene and is inherited from a relative. It can occur in both men and women as early as their 50s-60s.iv, viii

The wild-type form, which is thought to be more common, usually affects men after age 60 and is associated with aging.iiv, ix


[i] Maurer M, Elliott P, Comenzo R, et al. Addressing common questions encountered in the diagnosis and management of cardiac amyloidosis. Circulation. 2017. 135(14):1357-1377.
[ii] Ruberg FL, Berk JL. Transthyretin (TTR) cardiac amyloidosis. Circulation. 2012;126(10):1286-1300
[iii] Rapezzi C, Quarta CC, Riva L, et al. Transthyretin related amyloidoses and the heart: a clinical overview. Nat Rev Cardiol.2010;7:398-408.
[iv] Siddiqi O., Ruberg F. 2018. Cardiac Amyloidosis: An Update on Pathophysiology, Diagnosis, and Treatment. Trends Cardiovasc Med. DOI:10.1016/j.tcm.2017.07.004
[v] Nativi-Nicolau J, Maurer M. 2018. Amyloidosis Cardiomyopathy: Update in the Diagnosis and Treatment of the Most Common Types. Current Opinion. DOI:10.1097/HCO.0000000000000547
[vi] Maurer MS, Elliott P, Merlini G, et al. Design and Rationale of the Phase 3 ATTR-ACT Clinical Trial (Tafamidis in Transthyretin Cardiomyopathy Clinical Trial). Circ Heart Fail. 2017;10(6):e003815. doi:10.1161/CIRCHEARTFAILURE.116.003815
[vii] Rapezzi C, Lorenzini M, Longhi S, et al. Cardiac amyloidosis: the great pretender. Heart Fail Rev. 2015;20(2):117-124.
[viii] Swiecicki PL, Zhen DB, Mauermann ML, et al. Hereditary ATTR amyloidosis: a single-institution experience with 266 patients. Amyloid. 2015;22(2):123-131.
[ix] Mohammed SF, Mirzoyev SA, Edwards WD, et al. Left ventricular amyloid deposition in patients with heart failure and preserved ejection fraction. JACC Heart Fail. 2014;2(2):113-122.

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