General clinicians and junior paediatricians may have little experience of interpreting paediatric electrocardiograms. Although the basic principles of cardiac conduction and depolarisation are the same as for adults, age related changes in the anatomy and physiology of infants and children produce normal ranges for electrocardiographic features that differ from adults and vary with age. Awareness of these differences is the key to correct interpretation of paediatric electrocardiograms.
To obtain a satisfactory recording in young children requires patience, and the parents may be helpful in providing a source of distraction. Limb electrodes may be placed in a more proximal position to reduce movement artefacts. Standard adult electrode positions are used but with the addition of either lead V3R or lead V4R to detect right ventricular or atrial hypertrophy. Standard paper speed (25 mm/s) and deflection (10 mm/mV) are used, although occasionally large QRS complexes may require the gain to be halved.
Chest pain in children is rarely cardiac in origin and is often associated with tenderness in the chest wall. Electrocardiography is not usually helpful in making a diagnosis, although a normal trace can be very reassuring to the family. Typical indications for paediatric electrocardiography include syncope, exertional symptoms, tachyarrhythmias, bradyarrhythmias, and drug ingestion. Use of electrocardiography to evaluate congenital heart defects is a specialist interest and will not be discussed here.