Efficient Fetal-Maternal ECG Signal Separation from Two Channel Maternal Abdominal ECG via Diffusion-Based Channel Selection

Abstract

There is a need for affordable, widely deployable maternal-fetal ECG monitors to improve maternal and fetal health during pregnancy and delivery. Based on the diffusion-based channel selection, here we present the mathematical formalism and clinical validation of an algorithm capable of accurate separation of maternal and fetal ECG from a two channel signal acquired over maternal abdomen. The proposed algorithm is the first algorithm, to the best of the authors' knowledge, focusing on the fetal ECG analysis based on two channel maternal abdominal ECG signal, and we apply it to two publicly available databases, the PhysioNet non-invasive fECG database (adfecgdb) and the 2013 PhysioNet/Computing in Cardiology Challenge (CinC2013), to validate the algorithm. The state-of-the-art results are achieved when compared with other available algorithms. Particularly, the F₁ score for the R peak detection achieves 99.3% for the adfecgdb and 87.93% for the CinC2013, and the mean absolute error for the estimated R peak locations is 4.53 ms for the adfecgdb and 6.21 ms for the CinC2013. The method has the potential to be applied to other fetal cardiogenic signals, including cardiac doppler signals.

Keywords: de-shape short time Fourier transform; diffusion maps; fetal electrocardiogram; maternal abdominal electrocardiogram; nonlocal median.

Figure 1

The flow chart of the proposed two-channel fECG algorithm, SAVER. The x-axis of all figures are of the unit second. The data is the a2 recording from the database used in the 2013 PhysioNet/Computing in Cardiology Challenge, and channel 1 and channel 4 are shown in this illustration. Only three linear combinations are shown for the illustration purpose. The signal quality index for the channel selection is shown on the third block.

Figure 2

The lead placement for the adfecgdb.