A 9-independent-leads ECG system from 10 electrodes: A practice preserving WCT-less true unipolar ECG system

Since the invention of the 12-lead Electrocardiography (ECG) it is taught that only eight out of the twelve signals recordable from the nine exploring electrodes are linearly independent. It is also accepted practice the use of other four linearly dependent signals to add diagnostic efficacy. Unfortunately, quality and usefulness of the 12-lead signals is directly correlated with electrode placement precision and concerns have been raised around intentional misplacements of limb electrodes also for resting ECG. In this paper we show that with a simple modification to the recording front-end, nine independent signals (one per recording electrode) can be recorded. These signals can be used to reconstruct precisely the 12-lead signals (without information loss) and a plethora of other linearly dependent new signals that can open an unexplored frontier in cardiac illnesses diagnosis. While we need to carefully evaluate the clinical implications of our findings, we present here the proposed circuit and a case study (healthy subject) showing the number of signals achievable and we quantify the effect upon the ECG signals of one of the most common intentional misplacement of electrodes.