Taking a 12-lead ECG reading from a child or infant can be either a quick process with minimal fuss, or equally, it can be very stressful for the patient, their family or carer and the person performing the procedure. It is common for infants in particular to cry when they are undressed and cold, this can be problematic as this can cause an ‘artefact’ reading in the recording and reduce its value. By being as prepared and swift as possible, the outcome is likely to be better. It can be the case that a recording is simply too difficult due to an infant or child becoming too distressed. In the situation where distress could precipitate a crisis or collapse, it is best to stop and try later, relying on other clinical signs for information in the meantime. As the patient’s advocate, it is important to remain mindful of the whole child and if distress is likely to compromise the child, then stop the procedure.

As younger children and infants often find it scary being cold and having to lie still and become upset as a consequence, ensure all equipment is checked (plugged in or has sufficient charge) before commencing. Check the date and time are correct on the machine and that there is sufficient ECG paper and electrodes (at least 20). Ensure the electrodes are in date and appear sticky – they become less conductive with less adhesion. When this is all correct, then confirm the patient’s identity – request the patient’s full name and date of birth and check the procedure to be performed and obtain consent from the child, young person or their parent/carer. Ensure the patient is in the supine position if possible. If the patient is restless and distressed, the procedure may be performed with the patient in a sitting position, although this may give a poorer quality reading. Skin is a poor conductor of electricity, therefore good skin preparation is important; clean the skin, exfoliate if necessary with light abrasion using abrasive tape if adhesion is difficult or the skin has recently been moisturized – care should be taken in patients with sensitive or broken skin as this may aggravate their skin. Ensure the patient is relaxed and comfortable in order to reduce artefact, ensure visual confirmation of an artefact-free ECG trace on the display before pressing the appropriate record or print button on the ECG machine to obtain a resting 12-lead ECG reading.

Record a 12-lead ECG at 25 mm/sec with a gain setting of 10 mm/m unless instructed otherwise, for example, increasing the gain if the complexes are of a low voltage. This may be the case due to a number of clinical issues – if the recording appears low in voltage, take note of this and inform the person reading the ECG, this information could be critical. Ensure any change in gain is clearly marked on the printed ECG recording. If artefact remains, consider sources other than muscle tremor, for example, medical equipment or mobile phones. If it is safe to do so, turn off any equipment that may be causing the artefact. If you are unsure about the safety, check!

Despite being called a 12-lead ECG trace, it only involves 10 leads (but gives a view 12 ways). Positioning and accuracy are important as information is derived on the presumption that the leads are correctly placed. Regarding infants and younger children, standard chest and limb lead placements apply. However, if they are particularly distressed, the Mason-Likar lead placement can be used. Limb electrodes are placed anteriorly on the left and right shoulder and left and right side of the lower torso to reduce artefact caused by the movement of the limbs.

Record a 12-lead ECG at 25 mm/sec with a gain setting of 
10 mm/mV. Ensure the printed 12-lead ECG has all the correct details. If the ECG recording is technically correct and of good quality, then the leads and electrodes may be removed from the patient.

Artefact: Interference that may impact accurate ECG interpretation, including muscle tremor, wandering baseline, poor electrode contact, patient movement and limb lead reversal.

Electrocardiography: A recording of differences in action potential between sites on the body surface which vary during the cardiac cycle, reflecting differences in voltages within myocardial cells occurring during depolarization and repolarization within each cardiac cycle.

Gain: Size of the ECG trace.

Volt: A measure of electric potential at any point.