A 21 year old college student without any prior past medical history comes to the emergency room with complaints of palpitations and dizziness. She states he was at a party recently and had been drinking alcohol heavily when she noted the symptoms. No chest pains or shortness of breath. Her blood pressure is 110/70, heart rate 160, respirations 20, and oxygen saturation 95% on room air. A portion of his ECG is below. An echocardiogram is normal. Which of the following is the most appropriate management at this time?
A. Emergent direct current cardioversion
B. Intravenous amiodarone
C. Intravenous diltiazem