A 25-year-old woman comes to the emergency department due to sudden-onset palpitations, lightheadedness, and mild shortness of breath that began 30 minutes ago while at rest. She denies chest pain, syncope, or recent illness. Blood pressure is 110/70. An ECG is shown.
Which of the following is the most appropriate next step in management?
A) Adenosine
B) Amiodarone
C) Carotid massage
D) Synchronized cardioversion
E) Verapamil
