TTR and primary systemic amyloidosis: Systemic amyloidosis is a multisystem disease caused by the deposition of misfolded fibrillar protein in tissues and organs causing expansion of the extracellular space and impairment of function.1, 2 Cardiac involvement is a leading cause of morbidity and mortality, with two types commonly infiltrating the ventricular myocardium: immunoglobulin light-chain (AL) type and transthyretin (ATTR) type.3, 4, 5 With current or pending new treatment options for both,6, 7 improved diagnosis of cardiac involvement is becoming increasingly important.