Extramedullary plasmacytoma (EMP), characterized by infiltration of malignant plasmablastic clones outside the bone marrow in absence of multiple myeloma. Accounting for approximately 4% of all plasma cell dyscrasias, it has a predilection for head and neck region. However, in our presenting case we describe a 59-year-old man with primary plasmacytoma involving lumbar disc which is an exceedingly rare phenomenon. Antineoplastic drug arsenic trioxide (ATO) is predominantly a chemotherapeutic agent for acute promyelocytic leukemia has shown an immense cytotoxic effect on plasmacytoma. There's a growing recognition that enhanced therapeutic efficacy made ATO propitious for treating progressive and refractory EMP. After reviewed the existing literature, it's noteworthy that ATO acts as a trigger for cardiovascular diseases such as cardiac fibrosis, long QT syndrome, cardiotoxicity, torsades de pointes, ventricular tachycardia, cardiac fibroblast apoptosis, complete atrioventricular block, and sudden death. Inversely, based on potency and various practice guidelines, amiodarone is recommended for treating arrhythmias such as conversion of atrial fibrillation (AFib) to sinus rhythm or ventricular tachycardia. Herein we present a case of ATO induced AFib in a primary lumbar disc plasmacytoma diagnosed patient and amiodarone to prevent it.