An electrocardiogram (ECG) may be requested as part of the investigation of a wide range of problems in paediatrics, often in patients who have no clinical evidence of cardiac disease. Frequently the request is made by practitioners with no particular expertise in cardiology. The basic principles of interpretation of the ECG in children are identical to those in adults, but the progressive changes in anatomy and physiology which take place between birth and adolescence result in some features which differ significantly from the normal adult pattern and vary according to the age of the child. Correct interpretation of the ECG is therefore potentially difficult and a detailed knowledge of these age dependent changes is critically important if errors are to be avoided.

Extensive tables or centile charts of normal values in relation to age of patient are available.^1–3 There is the potential for computer support in the interpretation of the paediatric ECG,^4,5 sparing the interpreter the need to consult these tables or memorise large quantities of age dependant variables. However, there is published evidence⁶ which shows that some abnormalities are missed both by computer interpretation and by paediatric emergency department doctors. Equally, daily practice suggests that computer generated reports not infrequently identify an abnormality where none exists.

ELECTROCARDIOGRAPHIC VARIABLES

Until recently the most comprehensive study of electrocardiographic variables in childhood was that of Davignon¹ based on measurements made on 2141 white children in Quebec, Canada. Normal limits for 39 variables were presented as centile charts ranging from the 2nd to the 98th centile. These invaluable tables and charts are quoted in many major paediatric cardiology texts currently available, but some limitations must be recognised in the application of the data in practice today. Normal values for males and females were not separated. It may inappropriate to …