# A Complete Pipeline for Heart Rate Extraction from Infant ECGs
## 2 Materials and Results
### Datasets  
Three infant ECG datasets (Table 1) were used to develop the pipeline and test the existing approaches. Datasets A, B, and C were all captured using different devices with different sampling rates in different environments. Datasets A and B were characterised by relatively low levels of noise and were used to evaluate the ECG pipeline and initial HR processing. Some of the recordings in Dataset A had gaps in the recording due to Bluetooth dropout from the Biosignalsplux device (PLUX Biosignals, Lisbon, Portugal) (a subset of the recordings in Dataset A were the object of analyses in our previous work [13]). Dataset C contained the noisiest ECG (including areas of non-signal) and were used for HR quality analysis. Further details on these datasets can be found in Appendix B. The distribution of recording times and ages for each dataset is illustrated in Figure 3.  
A consistent issue across datasets was the range of ECG morphologies detected, such as double R-peaks and distorted T-waves. As infants are much smaller and less compliant than adults, ECG devices were often placed in a range of angles, and occasionally upside-down; therefore, the ECGs had to be evaluated individually to determine if the signal was inverted. The devices used often had very narrow electrodes, which made a traditional ECG notation (e.g., 12-lead analysis) difficult to apply.  
All datasets were recorded from subjects recruited from urban areas in the North-East of England. Families received remunerations commensurate with the specific study they were involved in, as well as an age-appropriate book as a token of participation. The research procedures were approved by the Ethics Committee of the Department of Psychology at the University of York. Participants' caregivers signed an informed consent form prior to the beginning of the research procedure.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Dataset** & **Device** & **Sampling Rate (Hz)** & **Environment** & **Age (Months)** & **\(n\)** & **Total Duration** & **Mean Duration** \\ \hline \multirow{8}{*}{A} & Biosignalsplux & & & 2.9–7.9 & 25 & 11 h, 41 min & 28 min, 1 s \\  & & & & 8–10.9 & 8–10.9 & 15 & 8 h, 35 min & 34 min, 20 s \\  & (PLUX & & Research lab, & & & \\ Biosignals, & Biosignals, & 500 & Free play in infant & 11–19.9 & 23 & 10 h, 41 min & 27 min, 52 s \\  & (Lisbon, & Portugal) & & & & 20–42.3 & 21 h, 41 min & 37 min, 45 s \\  & & & & & & \\  & & & & & & 14 min & 45 s \\ \cline{3-6}  & & & & **2.9–42.3** & **97** & **52 h, 20 min** & **32 min, 22 s** \\ \hline \multirow{8}{*}{B} & Geodesic EEG & & & 5.6–8.9 & 2 h, 13 min & 8 min, 52 s \\  & System (GES) & 1000 & Research lab, & & & \\ \cline{3-6}  & 400 (Magstim & & & & 10 & 11 h, 22 min & 12 s \\  & EGI, USA) & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \hline \multirow{8}{*}{C} & EgoActive & & Home & 5.3–7.9 & 10 h, 429 & 89 min, 37 s \\  & & Home & & & & 27 min & 37 s \\ \cline{3-6}  & & & & & 8–10.4 & 8–10.4 & 8–10.4 & 8–10.4 & 8–10.4 \\ \cline{3-6}  & (University of & & Free spontaneous & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \cline{3-6}  & & & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: The infant dataset information for the three datasets used in this paper. Age column shows the range and mean \(\pm\) standard deviation. A breakdown of durations by age cohort provided given along with the overall total (shown in bold).