New algorithm for fetal QRS detection in surface abdominal records

The proposed method detects fetal R waves on abdominal non-invasive records. An exponentially averaged pattern of the mother PQRST segment is obtained and subtracted. Subsequently the fetal R detector based on a Smoothed Nonlinear Energy Operator (SNEO) is applied to the residual signal. Finally, criteria about amplitude, heart rate and backward search are settled to correct false detections. To evaluate the fetal R detector, 10 multichannel records were used, acquired between gestation week 22 and 40. The position of the fetal R waves were manually marked (N=1490), and these reference marks were compared with the ones from the detector. It was obtained a 88.83% of sensitivity and a 91.32% of positive prediction value. The application of the detector to all the abdominal channels will probably allow improving the obtained results.