• Age \> 18 years for AL-CA, \> 65 years for ATTR-CA, \> 65 years for controls

• Willing and able to provide consent

• Diagnosis of systemic light chain amyloidosis by standard criteria (see below) and in hematological remission (normal serum free light chain levels)

‣ (immunofixation of serum and urine, IgG free light chain (FLC) assay, a biopsy of fat pad/ bone marrow, or organ biopsy, followed by typing of the light chain using immunohistochemistry or immunogold assay with confirmation by Mass spectroscopy as needed) AND

⁃ proof of cardiac involvement by AL amyloidosis

⁃ abnormal cardiac biomarkers (Abnormal high sensitivity TnT 5th generation levels (\>9 ng/L: female, \>14 ng/L: male) or abnormal age appropriate N terminal pro-brain natriuretic peptide, NT-proBNP (abnormal values: \<50 years: \>450 pg/ml; 50-75 years:\>900 pg/ml; \>75 years: \>1800 pg/ml) or

⁃ abnormal echocardiogram (wall thickness \> 12 mm) or

⁃ abnormal cardiac MRI (wall thickness \> 12 mm or extracellular volume \> 0.35) OR

• Diagnosis of transthyretin cardiac amyloidosis by standard criteria

‣ endomyocardial biopsy followed by typing of the transthyretin amyloidosis using immunohistochemistry or immunogold assay with confirmation by Mass spectroscopy as needed

⁃ extracardiac biopsy with typical cardiac imaging findings, or

⁃ grade 2 or grade 3 myocardial uptake of technetium-99m pyrophosphate (PYP) if AL amyloidosis is excluded