Best electrode locations for a small bipolar ECG device: signal strength analysis of clinical data.

New miniaturized portable electrocardiogram (ECG) measuring devices may require small interelectrode distance. However, finding a suitable location for a tiny measurement device may prove tedious, as reducing interelectrode distance reduces signal strength. The objective of the study was to define the optimal location for a very closely located (5 cm) bipolar electrode pair. A total of 120 bipolar leads were analyzed from a body surface potential map (BSPM) data with 236 subjects with a normal ECG. The average and standard deviation (SD) of the QRS-complex and the P-wave amplitudes in each electrode location and for each subject were determined. The results showed that deviation in signal amplitude between different subjects is significant. However, judging from average values, the best orientation for a closely located bipolar electrode pair is diagonally on the chest. The best locations for QRS-complex and P-wave detection are around the chest electrodes of the standard precordial leads V2, V3, and V4, and above the chest electrodes of leads V1 and V2, respectively.