Electrocardiogram acquisition and interpretation in children — branching viva

Opening question

This 14-year-old girl with two syncopal episodes has a Bazett-corrected QT interval of 490 milliseconds on her GP's ECG. Walk me through the systematic interpretation you would apply to her tracing, and tell me why the age-specific normal ranges matter at every step. [1] [2]

Branch 1 — technical conventions and electrode placement in a young child

Suppose instead you are asked to acquire an ECG in a wriggling two-year-old. Tell me the technical conventions you would confirm, how you would place the ten electrodes, and how you would obtain a tracing that is technically adequate rather than artefact-ridden. [2] [3]

Branch 2 — the neonatal ECG and the false positives of adult-range reading

A colleague hands you a neonatal ECG and reports "right axis deviation and right ventricular hypertrophy" on a day-three well baby. Is the colleague right? Defend your answer by stating the normal neonatal axis, the normal R-wave dominance in V1, and the normal T-wave pattern in V1 in the first week of life. [1] [2]

Branch 3 — the QTc, Bazett, and long QT syndrome

Return to the 14-year-old. Why is the QT interval corrected for heart rate, what is the weakness of Bazett's formula, and what threshold would you use to call her QTc prolonged? Tell me what you would ask about in the history and how you would confirm the diagnosis. [4] [5]

Closing — resuscitation of a haemodynamically compromised infant tachyarrhythmia

A three-month-old infant arrives pale and mottled with a heart rate of 250. What is the most likely rhythm, how would you distinguish it from sinus tachycardia, and what is the resuscitation pathway with the doses you would use? [2]