TTR and heart failure: Amyloidosis is a leading cause of infiltrative cardiomyopathy and in turn heart failure with preserved ejection fraction. Amyloidosis is mainly classified into amyloid light chain (AL) or primary amyloidosis and transthyretin amyloidosis (ATTR) that is subdivided into wild-type ATTR (ATTRwt) and hereditary or familial transthyretin-related amyloidosis (hATTR).