Nigerian Journal of Paediatrics (Jul 2024)
Paediatrics Electrocardiography
Abstract
Electrocardiogram (ECG) is a graphic recording of the electrical potential generated in the heart on the body surface using a device called electrocardiograph which was invented more than 100years ago by Eithoven. The cardiac muscle possesses intrinsic properties of automaticity, excitability and conductivity. Sinoatria (SA) node is the dominant pace maker. Therefore the electrical activity generated here spreads through the conduction tissue pathways, (i.e. atria, then to atrioventricular (AV) node, bundle of His and its branches, the purkinje system and ultimately to the ventricles resulting in an electrocardiographic complex consisting of PQRS- T during a cardiac cycle. One cardiac cycle is represented by successive wave forms on an electrocardiographic tracing, the P wave, QRS complex, and the T wave. These waves' produce two important intervals (PR and QT) and two segments (PQ and ST)., After the recording has been made, each strip of the electrocardiogram should be analyzed systematically for the following: Rate, rhythm, P waves, PR interval, QRS Axis, QRS morphology, QT interval, T wave, U wave and RS progression.Paediatric ECG is unique and difficult to interpret, but can be used within certain limits to identify anatomical, metabolic, ionic and hemodynamic abnormalities. Used alone as the basis of a clinical diagnosis the error margin could be quite wide. On the other hand, when used in the proper context, it is a very useful adjunct to cardiac diagnosis.
