The second reason is that using a bipolar and a unipolar lead (I and aVF) tends to make errors in the calculation, because the method of obtaining the EKG information is different and therefore the amplitudes of the QRS complexes are not fully comparable.
With the new formula, two bipolar leads are used, which are therefore equivalent.
Why have we not used this method of calculating the heart axis before?
Because determining the mathematical formula that allows the calculation has been much more complex, to the point that we have not observed this way of calculating the axis on another website, Most of these websites use, as we did, the leads I and aVF.
So we are pleased to assure you that with this improvement of our axis calculator, you will be able to get a value closer to the real heart axis.