Optimizing bipolar electrode location for wireless ECG measurement - analysis of ECG signal strength and deviation between individuals

New miniaturized portable ECG measuring devices may require reduced electrode size and distance. This paper introduces a project where the effect of interelectrode distance (IED) of ECG precordial electrodes was studied with Body Surface Potential Map (BSPM) data. The objective was to study how the IED affects the signal strength and how the electrode pair should be placed on the chest in order to obtain a sufficiently reliable and strong ECG signal. Two analyses were conducted for 17 bipolar leads in BSPM data: analysis of signal strength and deviation between patients, and analysis of signal strength compared to noise level. It was found out that for diagnostic purposes a bipolar measurement between standard electrodes V1 and V2 is not sufficient, as the P-wave may disappear due to noise. Nevertheless, if the bipolar electrode pair is placed in the direction of the heart's electrical axis, the P-wave amplitude is high enough for diagnose. For heart beat detection, even a quarter of the standard distance between V1 and V2 could be sufficient, as the QRS amplitude can be detected.