Clinical and Cardiovascular Magnetic Resonance Imaging Features of Cardiac Amyloidosis

Amyloidosis is a systemic disease characterized by the accumulation of insoluble aggregates in various organs, leading to parenchymal damage. When these amyloid fibrils are deposited in the extracellular matrix of the cardiac structures, the condition is referred to as cardiac amyloidosis (CA). The extent of organ involvement determines the degree of cardiac impairment, which can significantly impact prognosis. The two most implicated proteins in CA are transthyretin and misfolded monoclonal immunoglobulin light chains. These proteins give rise to two distinct clinical forms of CA: transthyretin amyloidosis (ATTR-CA) and light-chain amyloidosis (AL-CA). ATTR-CA is further classified into two subtypes: ATTRm-CA, which occurs at a younger age and is caused by hereditary misfolded mutated proteins, and ATTRwt-CA, which is an acquired wild-type form more commonly observed in older adults, referred to as senile amyloidosis. While AL-CA was considered the most prevalent form for many years, recent autopsy studies have revealed an increase in cases of ATTRwt-CA. This narrative review aims to describe the clinical and imaging features of CA, with a particular focus on cardiac complications and mortality associated with the AL form. Early identification and differentiation of CA from other disorders are crucial, given the higher risk and severity of cardiac involvement in AL-CA. Furthermore, emphasis is placed on the potential utility of cardiovascular magnetic resonance imaging in detecting early cases of CA.