Validation of A Novel Tattoo Electrode for ECG Monitoring

Giulia Baldazzi1, Andrea Spanu2, Antonello Mascia2, Graziana Viola3, Annalisa Bonfiglio2, Piero Cosseddu2, Danilo Pani4
1DIEE, University of Cagliari; DIBRIS, University of Genova;, 2DIEE, University of Cagliari, 3Department of Cardiology, San Francesco Hospital, 4DIEE - University of Cagliari


Aims: Tattoo electrodes allow unobtrusive biopotential recordings with a conformal skin-electrode interface, due to their extremely reduced thickness. In this work, the performance of novel ultrathin Parylene C-based dry electrodes was evaluated and compared to off-the-shelf gelled Ag/AgCl ones. Methods: Six 60s-long single-lead ECG signals were recorded from three voluntary healthy participants. Ag/AgCl and tattoo electrode signals were simultaneously acquired at 2048 Hz using the TMSi Porti7 system. To carry out a quantitative comparison, different figures of merit were computed for both acquisition methods. After a pre-processing stage, a state-of-the-art ECG delineator was adopted and the signal-to-noise ratio (SNR) and the RR intervals were computed on each recording for the signal quality evaluation. Moreover, in order to appreciate the similarity in signal morphology, the Pearson’s correlation coefficient was estimated for each pair of simultaneous heartbeats detected by the two electrodes. Finally, in order to determine also the low-frequency noise amount, the power of the baseline wandering artifact affecting each raw signal was quantified. Results: Heartbeat morphologies showed high correlation (0.999±0.001). Furthermore, both Ag/AgCl and tattoo acquisitions achieved high and similar SNRs (33±2 dB and 34±2 dB respectively) as long as comparable RR intervals (930 and 77 ms in terms of mean and standard deviation of the mean respectively, for both electrode types). However, tattoo electrode recordings suffered from slightly higher baseline wandering artifact (1.10±1.07 mV) than Ag/AgCl ones (0.08±0.04 mV). Conclusion: These findings suggest the possibility of successfully using this novel tattoo electrode for ECG monitoring, ensuring high consistency with respect to gelled Ag/AgCl electrodes. However, due to the limited number of subjects, validation on a larger dataset is needed, possibly including pathological ECG morphologies.