Failure to Confirm Typical Echocardiographic Findings of Cardiac Amyloidosis in an Unresolved Nonischemic Cardiomyopathy Associated With Smoldering Multiple Myeloma: A Case Report

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). Moreover, strain preservation pattern in the left ventricular apex in echocardiography suggests cardiac amyloidosis and cardiac magnetic resonance (CMR) could identify an infiltrative process. Similarly, the radiotracer uptake of technetium-99m pyrophosphate by myocardium could indicate transthyretin accumulation. In contrast, serum-free light chain (FLC) alongside serum and urine immunoelectrophoresis could indicate AL amyloidosis. Here, we present a case of a 60-year-old male with a classical apical sparing on echocardiography but with an unremarkable CMR and technetium-99 m pyrophosphate.