Multiple Myeloma Presenting as Cardiac Amyloidosis With Biventricular Failure: A Case Report

Cardiomyopathies related to amyloidosis are recognized as a type of infiltrative disorder; however, the degree of infiltration does not align with the severity of hemodynamic impairment. We present a case involving an elderly woman without any known comorbidities or substance use history who presented with congestive heart failure at our hospital. She had been treated with long-term diuretic therapy for heart failure by various physicians. A strong suspicion of primary cardiomyopathy was maintained given the absence of prior comorbidity after a comprehensive medical history review and examination. Two-dimensional echocardiography, protein electrophoresis, and bone marrow examination collectively revealed cardiac amyloidosis secondary to plasma cell dyscrasia. Standard heart failure treatment was initiated alongside chemotherapy; nonetheless, the patient experienced sudden cardiac death at home during followup. This case underscores the importance of early diagnosis and treatment of heart failure for patients with cardiac amyloidosis, and it also brings attention to the fact that cardiac amyloidosis can be the first sign of multiple myeloma.