Vectorcardiograms synthesized from 12-lead ECGs: a new method applied in 1792 healthy children.

The conventional 12-lead electrocardiogram (ECG) is the completely dominating recording technique in electrocardiography despite the superiority of the Frank vectorcardiogram (VCG) in certain situations. In adult cardiology, methods for synthesizing the VCG from the 12-lead ECG have been introduced to improve the interpretation of the 12-lead ECG by permitting VCG analysis in addition. A new method for synthesizing VCGs from 12-lead ECGs is presented and the resulting "12-lead VCGs" compared to Frank VCGs in a group of 21 children. There was good agreement between the two VCG methods. In addition, the "12-lead VCG" was studied in a group of 1792 apparently healthy children. A clockwise inscription of the loop in the horizontal plane was found in less than 1% of children above 1 month of age. The maximal QRS vector in the frontal plane was directed inferiorly and to the left in children older than 1 month of age, while its direction was superior and to the left in only seven children (0.4%). The usefulness of the 12-lead VCG as a tool in ECG interpretation still has to be assessed, but the normal limits presented here represent an important base for further study.