Amiodarone-induced thyrotoxicosis (AIT) is a complication of amiodarone therapy that can be difficult to diagnose and manage, especially in patients with dilated cardiomyopathy (DCM). We describe a 47-year-old female patient with DCM who experienced the sudden onset of type II AIT with symptoms mimicking low cardiac output syndrome, namely, general malaise and nausea. Early type II AIT was diagnosed, and effectively treated with prednisolone. <Learning objective: Amiodarone-induced thyrotoxicosis (AIT) is a complication of amiodarone therapy that can be difficult to diagnose and manage, especially in patients with dilated cardiomyopathy because of symptoms mimicking low cardiac output syndrome. We have to consider sudden onset of AIT in patients treated with amiodarone not to be late for appropriate management for it.>.