4th May 2025

A 23-year-old man presents to the acute medical unit for an assessment of his palpitations.

A 23-year-old man presents to the acute medical unit for an assessment of his palpitations. He is otherwise fit and well and takes no medications.

His 12-lead ECG shows a regular rhythm of 140bpm. No visible P waves are seen. His QRS complex is at 138ms and of a RBBB pattern. His QTC is 415ms. There is also right axis deviation

What is his most likely underlying rhythm?

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