RecruitingPhase 3Drug trial[64Cu]FBP8 PET for Early Detection of Intracardiac Thrombus in Amyloid CardiomyopathyThe primary goal of this pilot study is to determine whether \[64Cu\]FBP8, a novel fibrin-binding positron emission tomography (PET) probe, can identify intracardiac thrombi when paired with simultaneous hybrid cardiac PET/MRI in twenty (20) individuals with transthyretin or light chain cardiac amyloidosis and atrial fibrillation (AF) or atrial flutter (AF). The primary hypothesis of this study is that \[64Cu\]FBP8 PET/MRI can identify intracardiac thrombi in \>90% of subjects with confirmed intracardiac thrombi based on transesophageal echocardiogram (TEE). In secondary analyses, the investigators will seek to determine associations between intracardiac thrombi and left atrial function and left ventricular amyloid burden.