Transthyretin amyloidosis (ATTR) is a threatening and severe genetic disease characterized by damages to organs and systems caused by a pathological protein transthyretin produced in the liver. Clinical manifestations of this disease vary from injuries of the nervous system to injuries of the cardiovascular system. Prognosis for ATTR-amyloidosis remains unfavorable. The absence of pathognomonic symptoms complicates diagnostics of this disease, which tends to simulate other conditions. At present, medicines exist, which are pathogenetic in the treatment of ATTR-amyloidosis. The article describes a clinical case of ATTR-amyloidosis with primary heart injury complicated with functional class III chronic heart failure during the tafamidis treatment.