You are assessing a 68 year old male patient complaining of dizziness. The patient has pink, warm, and dry skin. BP 116/76, R 24 non-labored, P 184 and SpO2 96% on room air. Your ECG reveals a tachycardic rhythm with a QRS duration of 0.18 seconds. Which treatment would be appropriate?

A. Administer Amiodarone

B. Attempt vagal maneuvers

C. Perform cardioversion

D. Administer diltiazem