11th May 2025

A 50-year-old woman with known pulmonary hypertension presents to the emergency department complaining of palpitations.

A 50-year-old woman with known pulmonary hypertension presents to the emergency department complaining of palpitations. She described intermittent chest flutters associated with some mild breathlessness. She denies chest pain or syncope. She has some swelling in her ankles but says this has significantly improved since being started on furosemide. Examination reveals a loud P2, irregular tachycardic pulse, raised JVP and mild pedal oedema. Chest is clear. You perform an ECG which shows an irregular narrow complex arrhythmia at a rate of 124 beats per minute. The patient is admitted for further investigation and rate control. Which of the following would be the drug of choice in rate control of this patient? 

Select the SINGLE most appropriate option from the list below. Select ONE option only.