Cardiac amyloidosis is a condition in which misfolded proteins build up as amyloid fibrils in the heart muscle, causing it to stiffen and lose its normal ability to relax and fill with blood. Over time, this leads to heart failure, arrhythmias, and a range of related complications. The two most common forms seen in the heart are AL amyloidosis, caused by abnormal light chains produced by a clone of plasma cells, and ATTR amyloidosis, caused by misfolding of the transthyretin protein, which can occur in a hereditary form or, more commonly, as a wild-type disease of aging. Other, rarer amyloid types can also affect the heart.

Cardiac amyloidosis was once considered rare and difficult to diagnose, often missed until the disease was advanced. Improvements in imaging and a growing set of effective disease-modifying therapies have changed that picture substantially. Earlier diagnosis now means earlier treatment, and for many patients, meaningfully better outcomes. Recognizing the condition early, and referring patients to a clinic with the imaging, laboratory, and therapeutic expertise to manage it, remains the single biggest opportunity to improve how these patients do.