5th March 2024

A 64-year-old woman presents to the emergency department with dizziness and palpitations.

A 64-year-old woman presents to the emergency department with dizziness and palpitations. She stated that this started suddenly whilst watching the TV. She has a heart rate of 192 beats per minute, respiratory rate of 21 breaths per minute, blood pressure of 132/89mmHg and oxygen saturations of 98%. An ECG is performed which reveals a narrow-complex tachycardia, which the registrar suspects is a supra-ventricular tachycardia. She is trialled on vagal manoeuvres including the Valsalva manoeuvre and carotid sinus massage which both fail.

Please prescribe the initial dose of one medication that would be most suitable for treating this patient.