How many leads are necessary for a reliable reconstruction of surface potentials during atrial fibrillation?

In this study, we aimed at determining how many leads are necessary for accurately reconstructing ECG potentials during atrial fibrillation (AF) on the body surface. Although the standard ECG is appropriate for the detection of this arrhythmia, its accuracy for extracting other diagnostic features or constructing surface potential maps may not be optimal. We evaluated the suitability of the standard ECG in AF and proposed a new lead system for improving the information content of AF signals in limited lead systems. We made use of 64-lead body surface potential mapping recordings of 17 patients during AF and 18 healthy subjects. Lead selection was performed by making use of a lead selection algorithm proposed by Lux, and error curves were calculated for increasing number of selected leads for QRS complexes and P waves from healthy subjects and AF signals. From our results, at least 23 leads are needed in order to have the same degree of accuracy in the derivation of AF waves as the 12-lead ECG for a normal QRS complex (25% error). The 12-lead ECG allows a reconstruction of surface potentials with 53% error. If a limited lead set is to be chosen, a repositioning of only four electrodes from the standard ECG reduces reconstruction error in 11%. This repositioning of electrodes may include more right anterior electrodes and one posterior electrode.