Supraventricular tachycardia — branching viva

Examiner opening (Examiner)

You are the general paediatric registrar in the emergency department. A four-month-old boy is brought in pale and irritable with a heart rate of 250 per minute on the monitor. The 12-lead ECG shows a regular narrow-complex tachycardia with no visible P waves. Talk me through your assessment and management. ^[1]

Exemplar opening (Candidate)

This infant is in supraventricular tachycardia — the commonest significant arrhythmia of childhood — and he is showing early signs of haemodynamic compromise with pallor, irritability, and poor feeding. I will treat this as a time-critical presentation. First I confirm the airway, breathing, and circulation, attach continuous cardiac monitoring, and obtain intravenous access. Because he is pale and poorly perfused but not in overt shock, I will proceed with the stepwise termination ladder: a vagal manoeuvre first, then adenosine if needed, with a defibrillator at the bedside throughout. If he were unstable — hypotensive, in overt heart failure, or with altered consciousness — I would proceed directly to synchronised DC cardioversion without waiting for adenosine. ^{[1] [5]}