Visualizing the Novosel Formula: Comments on Dahl and Berg’s Formula for the Mean Electrical Axis of the Heart

The document discusses the calculation of the mean electrical axis of the heart (EA) from standard electrocardiogram (ECG) recordings, focusing on the 'Novosel Formula'. The authors emphasize three topics: the relationships between the limb leads, the visualization of the 'Novosel Formula', and the lack of standardization when calculating the EA. They propose using the leads with the highest amplitudes to estimate the EA. They also highlight that any combination of leads I/II/ III or aVR/aVL/aVF can be used without corrections to estimate the EA, but when a combination of bipolar and unipolar leads is used, a correction must be made. The authors call for the development of a standard for calculating the mean EA, as the lack of standardization can cause variability in large-scale research and "deep-data" analysis. They conclude that standardization of the algorithms in electrocardiographic devices would enable more precise analyses, comparisons, reproducibility, and reductions in unnecessary variability caused by the use of different formulas.