A young man with palpitations

Sam, a 38-year-old man, presents with intermittent rapid and irregular palpitations lasting for minutes to hours.


A recent ECG performed during a typical episode had shown atrial fibrillation; an ambulance rhythm strip recorded during symptoms was available for review (figure 1).

Cardiovascular examination was normal. He was subsequently started on verapamil by the initial treating doctor. A current 12-lead ECG is shown (figure 2).