Jack, a 61-year-old male, presented to the emergency department with a prolonged episode of palpitations of about 48 hours’ duration that had started after a run.
He had been experiencing intermittent palpitations for about six months, lasting for up to 30 minutes with no cause found after investigation by his GP.
The palpitations were sudden in onset, regular and rapid, with associated dyspnoea and lightheadedness. They typically occurred during exercise, but could also occur at rest.
He had no cardiac risk factors.
On presentation, clinical examination