Cardiac transthyretin amyloidosis (ATTR), caused by ventricular depositions of misfolded transthyretin, results in an infiltrative cardiomyopathy, progressing from pronounced myocardial wall thickening, diastolic and systolic dysfunction to the development of terminal heart failure. Recently, treatment options for TTR amyloidosis have become available. However costs for therapy are enormous and previous trials were not able to differentiate between patients that might benefit from treatment and those without a need for treatment. the investigators study aims to determine markers, as assessed by cardiac magnet resonance imaging (CMR) feature tracking (FT) and T1- and T2- mapping, that might reliably indicate disease severity and could help to identify patients that might benefit from (ongoing) TTR stabilization treatment.