Background: Primary amyloid light-chain (AL) amyloidosis results from plasmacell dyscrasia. Fibrillar deposits of monoclonal immunoglobulin light chains are present in various organs,especially in the heart. The patients suffer from fatal cardiac dysfunction. Case Report: We report thecase of a 54-year-old man with symptoms of cardiac arrhythmia which was refractory to conventional treatmentand ablations. At a later stage of his disease, the diagnosis of AL amyloidosis associated with monoclonalgammapathy of uncertain significance was established. Echocardiography, electrocardiography, serum immunofixationstudies, abdominal fat aspirate biopsy, and bone marrow biopsy indirectly confirmed the diagnosis ofcardiac amyloidosis. The patient died. Conclusions: The diagnosis of AL cardiac amyloidosis is difficult,the prognosis always serious, the available therapy limited, and the mortality high.

Keywords: Amyloidosis - ultrasonography, Amyloidosis - ultrasonography, Biopsy, Bone Marrow Cells - pathology, Cardiomyopathies - ultrasonography