Electrocardiogram acquisition and interpretation in children

Overview & Definition

Picture the six-week-old infant brought in with poor feeding and a fast heart rate, the eight-year-old who has fainted during a swimming lesson, or the teenager referred by the GP for an "abnormal ECG" after a routine check. In each case the question the ECG must answer is whether the electrical activity of the child's heart is normal for their age, and that question cannot be answered with adult ranges. That is the territory this page owns. [1] [2]

A 12-lead electrocardiogram (ECG) is the non-invasive recording, from ten surface electrodes (four limb and six precordial), of the summed electrical potentials generated by the myocardium over time and displayed as twelve different spatial views or leads. In a child the same physical principles apply as in the adult, but the normal ranges for heart rate, the PR and QRS intervals, the QRS axis, and the T-wave morphology all change with age, and the newborn ECG in particular is dominated by the right ventricle because the right heart has been working against the high pulmonary vascular resistance of fetal life. The discipline of the paediatric ECG is therefore to acquire a clean tracing and to interpret it against age-specific norms. [1] [9]

What distinguishes the paediatric ECG from the adult is a combination of a small, fast, often uncooperative patient and an electrical anatomy that is still maturing. The neonatal right ventricle is dominant, the intervals shorten with faster heart rates and lengthen as the heart grows, the T waves in V1 to V3 are normally inverted through childhood, and a number of channelopathies and congenital arrhythmias declare themselves on the surface ECG long before they declare themselves clinically. The fellowship skill being tested is acquiring a technically adequate tracing, interpreting it systematically against the correct age ranges, and recognising the patterns that demand urgent cardiology referral. [2] [6]